=====================================================================
 SIP - A Tool for Generating Python Bindings for C and C++ Libraries
=====================================================================

-----------------
 Reference Guide
-----------------

:Contact:   info@riverbankcomputing.co.uk
:Version:   4.1.1
:Copyright: Copyright (c) 2004 Riverbank Computing Limited

.. contents::
.. section-numbering::


Introduction
============

This is the reference guide for SIP 4.1.1.  SIP is a tool for
automatically generating `Python <http://www.python.org>`__ bindings for C and
C++ libraries.  SIP was originally developed in 1998 for
`PyQt <http://www.riverbankcomputing.co.uk/pyqt/>`__ - the Python bindings for
the Qt GUI toolkit - but is suitable for generating bindings for any C or C++
library.

This version of SIP generates bindings for Python v2.3 or later.  If you want
to generate bindings for earlier versions of Python (going back as far as
Python v1.5) then you need to use `SIP v3.x`_.

There are many other similar tools available.  One of the original such tools
is `SWIG <http://www.swig.org>`__ and, in fact, SIP is so called because it
started out as a small SWIG.  Unlike SWIG, SIP is specifically designed for
bringing together Python and C/C++ and goes to great lengths to make the
integration as tight as possible.

The homepage for SIP is http://www.riverbankcomputing.co.uk/sip/.  Here you
will always find the latest stable version, current development snapshots, and
the latest version of this documentation.


License
-------

SIP is licensed under the same terms as Python itself.  SIP places no
restrictions on the license you may apply to the bindings you create.


Features
--------

SIP, and the bindings it produces, have the following features.

    - bindings are fast to load and minimise memory consumption especially when
      only a small sub-set of a large library is being used

    - automatic conversion between standard Python and C/C++ data types

    - overloading of functions and methods with different argument signatures

    - access to a C++ class's protected methods

    - the ability to define a Python class that is a sub-class of a C++ class,
      including abstract C++ classes

    - support for ordinary C++ functions, class methods, static class methods,
      virtual class methods and abstract class methods

    - the ability to re-implement C++ virtual and abstract methods in Python

    - support for global and class variables

    - support for C++ namespaces

    - support for C++ exceptions and wrapping them as Python exceptions

    - the ability to define mappings between C++ classes and similar Python
      data types that are automatically invoked

    - the ability to automatically exploit any available run time type
      information to ensure that the class of a Python instance object matches
      the class of the corresponding C++ instance

    - full support of the Python interpreter lock, including the ability to
      specify that a C++ function of method may block, therefore allowing the
      lock to be released and other Python threads to run

    - support for the concept of ownership of a C++ instance (i.e. what part of
      the code is responsible for calling the instance's destructor) and how
      the ownership may change during the execution of an application

    - the ability to generate bindings for a C++ class library that itself is
      built on another C++ class library which also has had bindings generated
      so that the different bindings integrate and share code properly

    - a sophisticated versioning system that allows the full lifetime of a C++
      class library, including any platform specific or optional features, to
      be described in a single set of specification files 

    - the ability to include documentation in the specification files which can
      be extracted and subsequently processed by external tools

    - the ability to include copyright notices and licensing information in the
      specification files that is automatically included in all generated
      source code

    - a build system, written in Python, that you can extend to configure,
      compile and install your own bindings without worrying about platform
      specific issues

    - SIP, and the bindings it produces, runs under UNIX, Linux, Windows and
      MacOS/X

SIP also understands the signal/slot type safe callback mechanism implemented
by Qt.  SIP allows new Python signals to be defined, and allows any Python
callable object to be used as a slot.


SIP v3.x
--------

SIP v3.x differs from current versions in the following respects.

    - It uses Python's classic classes to wrap C++ classes (and so generated
      bindings can be built against any version of Python).

    - It does not support the creation of bindings for C libraries.

    - It does not generate bindings that will work on MacOS/X.

    - It is not formally documented.  However, most of this document does
      apply to SIP v3.x - just don't be surprised if you come across something
      that doesn't.

New releases of SIP v3.x may be made in the future, but no significant
development will be done.


SIP Components
--------------

SIP comprises a number of different components.

    - The SIP code generator (``sip`` or ``sip.exe``).  This processes ``.sip``
      specification files and generates C or C++ bindings.  It is covered in
      detail in `Using SIP`_.

    - The SIP header file (``sip.h``).  This contains definitions and data
      structures needed by the generated C and C++ code.

    - The SIP module (``sip.so`` or ``sip.pyd``).  This is a Python extension
      module that is imported automatically by SIP generated bindings and
      provides them with some common utility functions.  See also `Using the
      SIP Module in Applications`_.

    - The SIP build system (``sipconfig.py``).  This is a pure Python module
      that is created when SIP is configured and encapsulates all the necessary
      information about your system including relevant directory names,
      compiler and linker flags, and version numbers.  It also includes several
      Python classes and functions which help you write configuration scripts
      for your own bindings.  It is covered in detail in `The SIP Build
      System`_.


Installing SIP
==============

Downloading SIP
---------------

You can get the latest release of the SIP source code from
http://www.riverbankcomputing.co.uk/sip/download.php.

SIP is also included with all of the major Linux distributions.  However, it
may be a version or two out of date.

You may also find more up to date pre-compiled binaries on
`SourceForge <http://sourceforge.net/project/showfiles.php?group_id=61057>`_.


Configuring SIP
---------------

After unpacking the source package (either a ``.tar.gz`` or a ``.zip`` file
depending on your platform) you should then check for any ``README`` files
that relate to your platform.

Next you need to configure SIP by executing the ``configure.py`` script.  For
example::

    python configure.py

This assumes that the Python interpreter is on your path.  Something like the
following may be appropriate on Windows::

    c:\python23\python configure.py

If you have multiple versions of Python installed then make sure you use the
interpreter for which you wish SIP to generate bindings for.

Qt support is automatically enabled if the ``QTDIR`` environment variable is
set.  Use the ``-x`` command line option to disable it.

The full set of command line options is:

-h      Display a help message.
-b dir  The SIP code generator will be installed in the directory ``dir``.
-d dir  The SIP module will be installed in the directory ``dir``.
-e dir  The SIP header file will be installed in the directory ``dir``.
-k      The SIP module will be built as a static library.  This is useful when
        building the SIP module as a Python builtin
-l lib  Explicitly specify the type of Qt library to use, either ``qt``,
        ``qt-mt``, ``qtmt`` or ``qte``.  This is useful if, for example, you
        have the non-threaded (``qt``) and threaded (``qt-mt``) versions of
        the Qt library installed in the same directory.
-p platform
        Explicitly specify the platform/compiler to be used by the build
        system.  If Qt support is enabled then the platform/compiler used to
        build Qt will be used, otherwise a platform specific default will be
        used.  The ``-h`` option will display all the supported
        platform/compilers and the default.
-u      The SIP module will be built with debugging symbols.
-v dir  By default ``.sip`` files will be installed in the directory ``dir``.
-x      Disable the SIP module's support for Qt.  Support is automatically
        disabled if the ``QTDIR`` environment variables isn't set.

The configure.py script takes many other options that allows the build system
to be finely tuned.  These are of the form ``name=value`` or ``name+=value``.
The ``-h`` option will display each supported ``name``, although not all are
applicable to all platforms.

The ``name=value`` form means that ``value`` will replace the existing value of
``name``.

The ``name+=value`` form means that ``value`` will be appended to the existing
value of ``name``.

For example, the following will reduce the size of module binaries compiled
with GCC::

    python configure.py CXXFLAGS+=-fno-exceptions LFLAGS+=-s

A pure Python module called ``sipconfig.py`` is generated by ``configure.py``.
This defines each ``name`` and its corresponding ``value``.  Looking at it will
give you a good idea of how the build system uses the different options.  It is
covered in detail in `The SIP Build System`_.


Configuring SIP Using MinGW
***************************

SIP, and the modules it generates, can be built with MinGW, the Windows port of
GCC.  If you have Qt installed (and built with MinGW) then ``configure.py``
will automatically select the correct configuration.  If you do not have Qt
installed (or you are disabling support for it) then you must use the ``-p``
command line option to specify the correct platform.  For example::

    c:\python23\python configure.py -p win32-g++

You must also make sure you have a MinGW-compatible version of the Python
library.  See http://sebsauvage.net/python/mingw.html for instructions to do
this.


Configuring SIP Using the Borland C++ Compiler
**********************************************

SIP, and the modules it generates, can be built with the free Borland C++
compielr.  If you have Qt installed (and built with the Borland compiler) then
``configure.py`` will automatically select the correct configuration.  If you
do not have Qt installed (or you are disabling support for it) then you must
use the ``-p`` command line option to specify the correct platform.  For
example::

    c:\python23\python configure.py -p win32-borland

You must also make sure you have a Borland-compatible version of the Python
library.  If you are using the standard Python distribution (built using the
Microsoft compiler) then you must convert the format of the Python library.
For example::

    coff2omf python23.lib python23_bcpp.lib


Building SIP
------------

The next step is to build SIP by running your platform's ``make`` command.  For
example::

    make

The final step is to install SIP by running the following command::

    make install

(Depending on your system you may require root or administrator privileges.)

This will install the various SIP components.


Using SIP
=========

Bindings are generated by the SIP code generator from a number of specification
files, typically with a ``.sip`` extension.  Specification files look very
similar to C and C++ header files, but often with additional information (in
the form of a *directive* or an *annotation*) and code so that the bindings
generated can be finely tuned.


A Simple C++ Example
--------------------

We start with a simple, but complete, example.  Let's say you have a C++
library that implements a single class called ``Word``.  The class has one
constructor that takes a ``\0`` terminated character string as its single
argument.  The class has one method called ``reverse()`` which takes no
arguments and returns a ``\0`` terminated character string.  The interface to
the class is defined in a header file called ``word.h`` which might look
something like this::

    // Define the interface to the word library.

    class Word {
        const char *the_word;

    public:
        Word(const char *w);

        char *reverse() const;
    };

The corresponding SIP specification file would then look something like this::

    // Define the SIP wrapper to the word library.

    %Module word 0

    class Word {

    %TypeHeaderCode
    #include <word.h>
    %End

    public:
        Word(const char *);

        char *reverse() const;
    };

Obviously a SIP specification file looks very much like a C++ (or C) header
file, but SIP does not include a full C++ parser.  Let's look at the
differences between the two files.

    - The `%Module`_ directive has been added [#]_.  This is used to name the
      Python module that is being created and to give it a *generation* number.
      In this example these are ``word`` and ``0`` respectively.  The
      generation number is effectively the version number of the module.

    - The `%TypeHeaderCode`_ directive has been added.  The text between this
      and the following `%End`_ directive is included literally in the code
      that SIP generates.  Normally it is used, as in this case, to
      ``#include`` the corresponding C++ (or C) header file [#]_.

    - The declaration of the private variable ``this_word`` has been removed.
      SIP does not support access to either private or protected instance
      variables.

    - The name of the argument to the constructor has been removed.  SIP does
      not support named arguments [#]_.

If we want to we can now generate the C++ code in the current directory by
running the following command::

    sip -c . word.sip

However, that still leaves us with the task of compiling the generated code and
linking it against all the necessary libraries.  It's much easier to use the
SIP build system to do the whole thing.

Using the SIP build system is simply a matter of writing a small Python script.
In this simple example we will assume that the ``word`` library we are wrapping
and it's header file are installed in standard system locations and will be
found by the compiler and linker without having to specify any additional
flags.  In a more realistic example your Python script may take command line
options, or search a set of directories to deal with different configurations
and installations.

This is the simplest script (conventionally called ``configure.py``)::

    import os
    import sipconfig

    # The name of the SIP build file generated by SIP and used by the build
    # system.
    build_file = "word.sbf"

    # Get the SIP configuration information.
    config = sipconfig.Configuration()

    # Run SIP to generate the code.
    os.system(" ".join([config.sip_bin, "-c", ".", "-b", build_file, "word.sip"]))
    
    # Create the Makefile.
    makefile = sipconfig.SIPModuleMakefile(config, build_file)

    # Add the library we are wrapping.  The name doesn't include any platform
    # specific prefixes or extensions (e.g. the "lib" prefix on UNIX, or the
    # ".dll" extension on Windows).
    makefile.extra_libs = ["word"]

    # Generate the Makefile itself.
    makefile.generate()

Hopefully this script is self-documenting.  The key parts are the
``Configuration`` and ``SIPModuleMakefile`` classes.  The build system contains
other Makefile classes, for example to build programs or to call other
Makefiles in sub-directories.

After running the script (using the Python interpreter the extension module is
being created for) the generated C++ code and ``Makefile`` will be in the
current directory.

To compile and install the extension module, just run the following
commands [#]_::

    make
    make install

That's all there is to it.

.. [#] All SIP directives start with a ``%`` as the first non-whitespace
       character of a line.
.. [#] SIP includes many code directives like this.  They differ in where the
       supplied code is placed by SIP in the generated code.
.. [#] It is planned that a future version of SIP will allow arguments to be
       named and that the names will be used as Python keyword arguments.
.. [#] On Windows you might run ``nmake`` or ``mingw32-make`` instead.


A Simple C Example
------------------

Let's now look at a very similar example of wrapping a C library::

    /* Define the interface to the word library. */

    struct Word {
        const char *the_word;
    };

    struct Word *create_word(const char *w);
    char *reverse(struct Word *word);

The corresponding SIP specification file would then look something like this::

    /* Define the SIP wrapper to the word library. */

    %CModule word 0

    struct Word {

    %TypeHeaderCode
    #include <word.h>
    %End

        const char *the_word;
    };

    struct Word *create_word(const char *);
    char *reverse(struct Word *);

Again, let's look at the differences between the two files.

    - The `%CModule`_ directive has been added.  This has the same syntax as
      the `%Module`_ directive used in the previous example but tells SIP that
      the library being wrapped is implemented in C rather than C++.

    - The `%TypeHeaderCode`_ directive has been added.

    - The names of the arguments to the functions have been removed.

The ``configure.py`` build system script described in the previous example can
be used for this example without change.


A More Complex C++ Example
--------------------------

In this last example we will wrap a C++ library that contains a class that is
derived from a Qt class.  This will demonstrate how SIP allows a class
hierarchy to be split across multiple Python extension modules, and will
introduce SIP's versioning system.

The library contains a single C++ class called ``Hello`` which is derived from
Qt's ``QLabel`` class.  It behaves just like ``QLabel`` except that the text
in the label is hard coded to be ``Hello World``.  To make the example more
interesting we'll also say that the library only supports Qt v3.0 and later,
and also includes a function called ``setDefault()`` that is not implemented
in the Windows version of the library.

The ``hello.h`` header file looks something like this::

    // Define the interface to the hello library.

    #include <qlabel.h>
    #include <qwidget.h>
    #include <qstring.h>

    class Hello : public QLabel {
        // This is needed by the Qt Meta-Object Compiler.
        Q_OBJECT

    public:
        Hello(QWidget *parent, const char *name = 0, WFlags f = 0);

    private:
        // Prevent instances from being copied.
        Hello(const Hello &);
        Hello &operator=(const Hello &);
    };

    #if !defined(Q_OS_WIN)
    void setDefault(const QString &def);
    #endif

The corresponding SIP specification file would then look something like this::

    // Define the SIP wrapper to the hello library.

    %Module hello 0

    %Import qt/qtmod.sip

    %If (Qt_3_0_0 -)

    class Hello : QLabel {

    %TypeHeaderCode
    #include <hello.h>
    %End

    public:
        Hello(QWidget * /TransferThis/, const char * = 0, WFlags = 0);

    private:
        Hello(const Hello &);
    };

    %If (!WS_WIN)
    void setDefault(const QString &);
    %End

    %End

Again we look at the differences, but we'll skip those that we've looked at in
previous examples.

    - The `%Import`_ directive has been added to specify that we are extending
      the class hierarchy defined in the file ``qt/qtmod.sip``.  This file is
      part of PyQt.  The build system will take care of finding the file's
      exact location.

    - The `%If`_ directive has been added to specify that
      everything [#]_ up to the matching `%End`_ directive only applies to Qt
      v3.0 and later.  ``Qt_3_0_0`` is a *tag* defined in ``qtmod.sip`` [#]_
      using the `%Timeline`_ directive.  `%Timeline`_ is used to define a tag
      for each version of a library's API you are wrapping allowing you to
      maintain all the different versions in a single SIP specification.  The
      build system provides support to ``configure.py`` scripts for working out
      the correct tags to use according to which version of the library is
      actually installed.

    - The ``public`` keyword used in defining the super-classes has been
      removed.  This is not supported by SIP.

    - The TransferThis_ annotation has been added to the first argument
      of the constructor.  It specifies that if the argument is not 0 (i.e. the
      ``Hello`` instance being constructed has a parent) then ownership of the
      instance is transferred from Python to C++.  It is needed because Qt
      maintains objects (i.e. instances derived from the ``QObject`` class) in
      a hierachy.  When an object is destroyed all of its children are also
      automatically destroyed.  It is important, therefore, that the Python
      garbage collector doesn't also try and destroy them.  This is covered in
      more detail in `Ownership of Objects`_.  SIP provides many other
      annotations that can be applied to arguments, functions and classes.
      Multiple annotations are separated by commas.  Annotations may have
      values.

    - The ``=`` operator has been removed.  This operator is not supported by
      SIP.

    - The `%If`_ directive has been added to specify that everything up to the
      matching `%End`_ directive does not apply to Windows.  ``WS_WIN`` is
      another tag defined by PyQt, this time using the `%Platforms`_ directive.
      Tags defined by the `%Platforms`_ directive are mutually exclusive, i.e.
      only one may be valid at a time [#]_.

One question you might have at this point is why bother to define the private
copy constructor when it can never be called from Python?  The answer is to
prevent the automatic generation of a public copy constructor.

We now look at the ``configure.py`` script.  This is a little different to the
script in the previous examples for two related reasons.

Firstly, PyQt includes a pure Python module called ``pyqtconfig`` that extends
the SIP build system for modules, like our example, that build on top of PyQt.
It deals with the details of which version of Qt is being used (i.e. it
determines what the correct tags are) and where it is installed.  This is
called a module's configuration module.

Secondly, we generate a configuration module (called ``helloconfig``) for our
own ``hello`` module.  There is no need to do this, but if there is a chance
that somebody else might want to extend your C++ library then it would make
life easier for them.

Now we have two scripts.  First the ``configure.py`` script::

    import os
    import sipconfig
    import pyqtconfig

    # The name of the SIP build file generated by SIP and used by the build
    # system.
    build_file = "hello.sbf"

    # Get the PyQt configuration information.
    config = pyqtconfig.Configuration()

    # Get the extra SIP flags needed by the imported qt module.  Note that
    # this normally only includes those flags (-x and -t) that relate to SIP's
    # versioning system.
    qt_sip_flags = config.pyqt_qt_sip_flags

    # Run SIP to generate the code.  Note that we tell SIP where to find the qt
    # module's specification files using the -I flag.
    os.system(" ".join([config.sip_bin, "-c", ".", "-b", build_file, "-I", config.pyqt_sip_dir, qt_sip_flags, "hello.sip"]))

    # We are going to install the SIP specification file for this module and
    # its configuration module.
    installs = []

    installs.append(["hello.sip", os.path.join(config.default_sip_dir, "hello")])

    installs.append(["helloconfig.py", config.default_mod_dir])

    # Create the Makefile.  The QtModuleMakefile class provided by the
    # pyqtconfig module takes care of all the extra preprocessor, compiler and
    # linker flags needed by the Qt library.
    makefile = pyqtconfig.QtModuleMakefile(
        configuration=config,
        build_file=build_file,
        installs=installs
    )

    # Add the library we are wrapping.  The name doesn't include any platform
    # specific prefixes or extensions (e.g. the "lib" prefix on UNIX, or the
    # ".dll" extension on Windows).
    makefile.extra_libs = ["hello"]

    # Generate the Makefile itself.
    makefile.generate()

    # Now we create the configuration module.  This is done by merging a Python
    # dictionary (whose values are normally determined dynamically) with a
    # (static) template.
    content = {
        # Publish where the SIP specifications for this module will be
        # installed.
        "hello_sip_dir":    config.default_sip_dir,

        # Publish the set of SIP flags needed by this module.  As these are the
        # same flags needed by the qt module we could leave it out, but this
        # allows us to change the flags at a later date without breaking
        # scripts that import the configuration module.
        "hello_sip_flags":  qt_sip_flags
    }

    # This creates the helloconfig.py module from the helloconfig.py.in
    # template and the dictionary.
    sipconfig.create_config_module("helloconfig.py", "helloconfig.py.in", content)

Next we have the ``helloconfig.py.in`` template script::

    import pyqtconfig

    # These are installation specific values created when Hello was configured.
    # The following line will be replaced when this template is used to create
    # the final configuration module.
    # @SIP_CONFIGURATION@

    class Configuration(pyqtconfig.Configuration):
        """The class that represents Hello configuration values.
        """
        def __init__(self, sub_cfg=None):
            """Initialise an instance of the class.

            sub_cfg is the list of sub-class configurations.  It should be None
            when called normally.
            """
            # This is all standard code to be copied verbatim except for the
            # name of the module containing the super-class.
            if sub_cfg:
                cfg = sub_cfg
            else:
                cfg = []

            cfg.append(_pkg_config)

            pyqtconfig.Configuration.__init__(self, cfg)

    class HelloModuleMakefile(pyqtconfig.QtModuleMakefile):
        """The Makefile class for modules that %Import hello.
        """
        def finalise(self):
            """Finalise the macros.
            """
            # Make sure our C++ library is linked.
            self.extra_libs.append("hello")

            # Let the super-class do what it needs to.
            pyqtconfig.QtModuleMakefile.finalise(self)

Again, we hope that the scripts are self documenting.

.. [#] Some parts of a SIP specification aren't subject to version control.
.. [#] Actually in ``versions.sip``.  PyQt uses the `%Include`_ directive to
       split the SIP specification for Qt across a large number of separate
       ``.sip`` files.
.. [#] Tags can also be defined by the `%Feature`_ directive.  These tags are
       not mutually exclusive, i.e. any number may be valid at a time.


Ownership of Objects
--------------------

When a C++ instance is wrapped a corresponding Python object is created.  The
Python object behaves as you would expect in regard to garbage collection - it
is garbage collected when its reference count reaches zero.  What then happens
to the corresponding C++ instance?  The obvious answer might be that the
instance's destructor is called.  However the library API may say that when the
instance is passed to a particular function, the library takes ownership of the
instance, i.e. responsibility for calling the instance's destructor is
transferred from the SIP generated module to the library.

The TransferThis_, Transfer_ and TransferBack_ annotations are used to specify
where, and it what direction, transfers of ownership happen.  It is very
important that these are specified correctly to avoid crashes (where both
Python and C++ call the destructor) and memory leaks (where neither Python and
C++ call the destructor).

This applies equally to C structures where the structure is returned to the
heap using the ``free()`` function.

See also `sipTransfer()`_.


The SIP Command Line
====================

The syntax of the SIP command line is::

    sip [options] [specification]

``specification`` is the name of the specification file for the module.  If it
is omitted then ``stdin`` is used.

The full set of command line options is:

-h      Display a help message.
-V      Display the SIP version number.
-a file
        The name of the Scintilla API file to generate.  This file contains a
        description of the module API in a form that the Scintilla editor
        component can use for auto-completion and call tips.  By default the
        file is not generated.
-b file
        The name of the build file to generate.  This file contains the
        information about the module needed by the SIP build system to generate
        a platform and compiler specific Makefile for the module.  By default
        the file is not generated.
-c dir  The name of the directory (which must exist) into which all of the
        generated C or C++ code is placed.  By default no code is generated.
-d file
        The name of the documentation file to generate.  Documentation is
        included in specification files using the `%Doc`_ and `%ExportedDoc`_
        directives.  By default the file is not generated.
-e      Support for C++ exceptions is enabled.  The causes all calls to C++
        code to be enclosed in ``try``/``catch`` blocks and C++ exceptions to
        be converted to Python exceptions.  By default exception support is
        disabled.
-g      The GIL is always released when making calls to C or C++ code and
        reacquired on return.  (This is the SIP v3.x behaviour.)  By default
        the enhanced GIL management functions described in PEP 311 are used so
        that the GIL is released only when necessary.
-I dir  The directory is added to the list of directories searched when looking
        for a specification file given in an `%Include`_ or `%Import`_
        directive.  This option may be given any number of times.
-j number
        The generated code is split into the given number of files.  This make
        it easier to use the parallel build facility of most modern
        implementations of ``make``.  By default 1 file is generated for each C
        structure or C++ class.
-r      Debugging statements that trace the execution of the bindings are
        automatically generated.  By default the statements are not generated.
-s suffix
        The suffix to use for generated C or C++ source files.  By default
        ``.c`` is used for C and ``.cpp`` for C++.
-t tag  The SIP version tag (declared using the `%Timeline`_ directive) or the
        SIP platform tag (declared using the `%Platforms`_ directive) to
        generate code for.  This option may be given any number of times so
        long as the tags do not conflict.
-w      The display of warning messages is enabled.  By default warning
        messages are disabled.
-x feature
        The feature (declared using the `%Feature`_ directive) is disabled.
-z file
        The name of a file containing more command line options.


SIP Specification Files
=======================

A SIP specification consists of some C/C++ type and function declarations and
some directives.  The declarations may contain annotations which provide SIP
with additional information that cannot be expressed in C/C++.  SIP does not
include a full C/C++ parser.

It is important to understand that a SIP specification describes the Python
API, i.e. the API available to the Python programmer when they ``import`` the
generated module.  It does not have to accurately represent the underlying
C/C++ library.  There is nothing wrong with omitting functions that make
little sense in a Python context, or adding functions implemented with
handwritten code that have no C/C++ equivalent.  It is even possible (and
sometimes necessary) to specify a different super-class hierarchy for a C++
class.  All that matters is that the generated code compiles properly.

In most cases the Python API matches the C/C++ API.  In some cases handwritten
code (see `%MethodCode`_) is used to map from one to the other without SIP
having to know the details itself.  However, there are a few cases where SIP
generates a thin wrapper around a C++ method or constructor (see `Generated
Derived Classes`_) and needs to know the exact C++ signature.  To deal with
these cases SIP allows two signatures to be specified.  For example::

    class Klass
    {
    public:
        // The Python signature is a tuple, but the underlying C++ signature
        // is a 2 element array.
        Klass(SIP_PYTUPLE) [(int *)];
    %MethodCode
            int iarr[2];

            if (PyArg_ParseTuple(a0, "ii", &iarr[0], &iarr[1]))
            {
                // Note that we use the SIP generated derived class
                // constructor.
                Py_BEGIN_ALLOW_THREADS
                sipCpp = new sipKlass(iarr);
                Py_END_ALLOW_THREADS
            }
    %End
    };


Syntax Definition
-----------------

The following is a semi-formal description of the syntax of a specification
file.

.. parsed-literal::

    *specification* ::= {*module-statement*}

    *module-statement* ::= [*module-directive* | *statement*]

    *module-directive* ::= [`%CModule`_ | `%Copying`_ | `%Doc`_ |
            `%ExportedDoc`_ | `%Feature`_ | `%Import`_ | `%Include`_ |
            `%License`_ | `%MappedType`_ `%Module`_ | `%ModuleCode`_ |
            `%ModuleHeaderCode`_ | `%OptionalInclude`_ | `%Platforms`_ |
            `%PostInitialisationCode`_ | `%Timeline`_]

    *statement* :: [*class-statement* | *function* | *variable*]

    *class-statement* :: [`%If`_ | *class* | *enum* | *namespace* |
            *opaque-class* | *struct* | *typedef*]

    *class* ::= ``class`` *name* [``:`` *super-classes*] [*class-annotations*]
            ``{`` {*class-line*} ``};``

    *super-classes* ::= *name* [``,`` *super-classes*]

    *class-line* ::= [*class-statement* | `%ConvertToSubClassCode`_ |
            `%ConvertToTypeCode`_ | `%TypeCode`_ | `%TypeHeaderCode`_ |
            *constructor* | *destructor* | *method* | *static-method* |
            *virtual-method* | *special-method* | *operator* |
            *class-variable* | ``public:`` | ``public slots:`` |
            ``protected:`` | ``protected slots:`` | ``private:`` |
            ``private slots:`` | ``signals:``]

    *constructor* ::= *name* ``(`` [*argument-list*] ``)`` [*exceptions*]
            [*function-annotations*] [*c++-constructor-signature*] ``;``
            [`%MethodCode`_]

    *c++-constructor-signature* ::= ``[(`` [*argument-list*] ``)]``

    *destructor* ::= [``virtual``] ``~`` *name* ``()`` [*exceptions*]
            [*function-annotations*] ``;`` [`%MethodCode`_]
            [`%VirtualCatcherCode`_]

    *method* ::= *type* *name* ``(`` [*argument-list*] ``)`` [``const``]
            [*exceptions*] [``= 0``] [*function-annotations*] [*c++-signature*]
            ``;`` [`%MethodCode`_]

    *c++-signature* ::= ``[`` *type* ``(`` [*argument-list*] ``)]``

    *static-method* ::= ``static`` *function*

    *virtual-method* ::= ``virtual`` *type* *name* ``(`` [*argument-list*] ``)``
            [``const``] [*exceptions*] [``= 0``] [*function-annotations*]
            [*c++-signature*] ``;`` [`%MethodCode`_] [`%VirtualCatcherCode`_]

    *special-method* ::= *type* *special-method-name*
            ``(`` [*argument-list*] ``)`` [*function-annotations*] ``;``
            [`%MethodCode`_]

    *special-method-name* ::= [ ``__add__`` | ``__and__`` | ``__call__`` |
            ``__cmp__`` | ``__contains__`` | ``__delitem__`` | ``__div__`` |
            ``__eq__`` | ``__ge__`` | ``__getitem__`` | ``__gt__`` |
            ``__iadd__`` | ``__iand__`` | ``__idiv__`` | ``__ilshift__`` |
            ``__imod__`` | ``__imul__`` | ``__int__`` | ``__invert__`` |
            ``__ior__`` | ``__irshift__`` | ``__isub__`` | ``__ixor__`` |
            ``__le__`` | ``__len__`` | ``__lshift__`` | ``__lt__`` |
            ``__mod__`` | ``__mul__`` | ``__ne__`` | ``__neg__`` |
            ``__nonzero__`` | ``__or__`` | ``__repr__`` | ``__rshift__`` |
            ``__setitem__`` | ``__str__`` | ``__sub__`` | ``__unicode__`` |
            ``__xor__``]

    *operator* ::= *type* ``operator`` *operator-name*
            ``(`` [*argument-list*] ``)`` [``const``] [*exceptions*]
            [*function-annotations*] ``;`` [`%MethodCode`_]

    *operator-name* ::= [``+`` | ``-`` | ``*`` | ``/`` | ``%`` | ``&`` |
            ``|`` | ``^`` | ``<<`` | ``>>`` | ``+=`` | ``-=`` | ``*=`` |
            ``/=`` | ``%=`` | ``&=`` | ``|=`` | ``^=`` | ``<<=`` | ``>>=`` |
            ``~`` | ``()`` | ``[]`` | ``<`` | ``<=`` | ``==`` | ``!=`` |
            ``>`` | ``>>=``]

    *class-variable* ::= [``static``] *variable*

    *enum* ::= ``enum`` [*name*] ``{`` {*enum-line*} ``};``

    *enum-line* ::= [`%If`_ | *name*]

    *function* ::= *type* *name* ``(`` [*argument-list*] ``)`` [*exceptions*]
            [*function-annotations*] ``;`` [`%MethodCode`_]

    *namespace* ::= ``namespace`` *name* ``{`` {*namespace-line*} ``};``

    *namespace-line* ::= *statement*

    *opaque-class* ::= ``class`` *scoped-name* ``;``

    *struct* ::= ``struct`` *name* ``{`` {*class-line*} ``};``

    *typedef* ::= ``typedef`` [*typed-name* | *function-pointer*] ``;``

    *variable*::= *typed-name* ``;`` [`%AccessCode`_]

    *exceptions* ::= ``throw (`` [*exception-list*] ``)``

    *exception-list* ::= *scoped-name* [``,`` *exception-list*]

    *argument-list* ::= *argument* [``,`` *argument-list*]

    *argument* ::= [*type* [*argument-annotations*] [*default-value*] | 
            SIP_QOBJECT_ | SIP_RXOBJ_CON_ | SIP_RXOBJ_DIS_ | SIP_SIGNAL_ |
            SIP_SLOT_ | SIP_SLOT_CON()_ | SIP_SLOT_DIS()_]

    *default-value* ::= ``=`` *expression*

    *expression* ::= [*value* | *value* *binary-operator* *expression*]

    *value* ::= [*unary-operator*] *simple-value*

    *simple-value* ::= [*scoped-name* | *function-call* | *real-value* |
            *integer-value* | *boolean-value* | *string-value* |
            *character-value*]

    *typed-name*::= *type* *name*

    *function-pointer*::= *type* ``(*`` *name* ``)(`` [*type-list*] ``)``

    *type-list* ::= *type* [``,`` *type-list*]

    *function-call* ::= *scoped-name* ``(`` [*value-list*] ``)``

    *value-list* ::= *value* [``,`` *value-list*]

    *real-value* ::= a floating point number

    *integer-value* ::= a number

    *boolean-value* ::= [``true`` | ``false``]

    *string-value* ::= ``"`` {*character*} ``"``

    *character-value* ::= ````` *character* `````

    *unary-operator* ::= [``!`` | ``~`` | ``-`` | ``+``]

    *binary-operator* ::= [``-`` | ``+`` | ``*`` | ``/`` | ``&`` | ``|``]

    *argument-annotations* ::= see `Argument Annotations`_

    *class-annotations* ::= see `Class Annotations`_

    *function-annotations* ::= see `Function Annotations`_

    *type* ::= [``const``] *base-type* {``*``} [``&``]

    *type-list* ::= *type* [``,`` *type-list*]

    *base-type* ::= [*scoped-name* | *template* | ``struct`` *scoped-name* |
            ``short`` | ``unsigned short`` | ``int`` | ``unsigned`` |
            ``unsigned int`` | ``long`` | ``unsigned long`` | ``float`` |
            ``double`` | ``bool`` | ``char`` | ``unsigned char`` | ``void`` |
            SIP_PYCALLABLE_ | SIP_PYDICT_ | SIP_PYLIST_ | SIP_PYOBJECT_ |
            SIP_PYSLICE_ | SIP_PYTUPLE_]

    *scoped-name* ::= *name* [``::`` *scoped-name*]

    *template* ::= *scoped-name* ``<`` *type-list* ``>``

    *name* ::= _A-Za-z {_A-Za-z0-9}

Here is a short list of differences between C++ and the subset supported by
SIP that might trip you up.

    - SIP does not support the use of ``[]`` in types.  Use pointers instead.

    - ``operator`` can only be used in a class.

    - Variables declared outside of a class are effectively read-only.

    - Functions and methods do not support argument names.

    - A class's list of super-classes doesn't not include any access specifier
      (e.g. ``public``).


Additional SIP Types
--------------------

SIP supports a number of additional data types that can be used in Python
signatures.


SIP_PYCALLABLE
**************

This is a ``PyObject *`` that is a Python callable object.


SIP_PYDICT
**********

This is a ``PyObject *`` that is a Python dictionary object.


SIP_PYLIST
**********

This is a ``PyObject *`` that is a Python list object.


SIP_PYOBJECT
************

This is a ``PyObject *`` of any Python type.


SIP_PYSLICE
***********

This is a ``PyObject *`` that is a Python slice object.


SIP_PYTUPLE
***********

This is a ``PyObject *`` that is a Python tuple object.


SIP_QOBJECT
***********

This is a ``QObject *`` that is a C++ instance of a class derived from Qt's
``QObject`` class.


SIP_RXOBJ_CON
*************

This is a ``QObject *`` that is a C++ instance of a class derived from Qt's
``QObject`` class.  It is used as the type of the receiver instead of ``const
QObject *`` in functions that implement a connection to a slot.


SIP_RXOBJ_DIS
*************

This is a ``QObject *`` that is a C++ instance of a class derived from Qt's
``QObject`` class.  It is used as the type of the receiver instead of ``const
QObject *`` in functions that implement a disconnection from a slot.


SIP_SIGNAL
**********

This is a ``const char *`` that is used as the type of the signal instead of
``const char *`` in functions that implement the connection or disconnection
of an explicitly generated signal to a slot.


SIP_SLOT
********

This is a ``const char *`` that is used as the type of the member instead of
``const char *`` in functions that implement the connection or disconnection
of an explicitly generated signal to a slot.


SIP_SLOT_CON()
**************

This is a ``const char *`` that is used as the type of the member instead of
``const char *`` in functions that implement the connection of an internally
generated signal to a slot.  The type includes a comma separated list of types
that is the C++ signature of of the signal.

To take an example, ``QAccel::connectItem()`` connects an internally generated
signal to a slot.  The signal is emitted when the keyboard accelerator is
activated and it has a single integer argument that is the ID of the
accelerator.  The C++ signature is::

    bool connectItem(int id, const QObject *receiver, const char *member);

The corresponding SIP specification is::

    bool connectItem(int, SIP_RXOBJ_CON, SIP_SLOT_CON(int));


SIP_SLOT_DIS()
**************

This is a ``const char *`` that is used as the type of the member instead of
``const char *`` in functions that implement the disconnection of an
internally generated signal to a slot.  The type includes a comma separated
list of types that is the C++ signature of of the signal.


SIP Directives
==============

In this section we describe each of the directives that can be used in
specification files.  All directives begin with ``%`` as the first
non-whitespace character in a line.

Some directives have arguments or contain blocks of code or documentation.  In
the following descriptions these are shown in *italics*.  Optional arguments
are enclosed in [*brackets*].

Some directives are used to specify handwritten code.  Handwritten code must
not define names that start with the prefix ``sip``.


%AccessCode
-----------

.. parsed-literal::

    %AccessCode
        *code*
    %End

This directive is used immediately after the declaration of an instance of a
wrapped class or structure, or a pointer to such an instance.  You use it to
provide handwritten code that overrides the default behaviour.

For example::

    class Klass;

    Klass *klassInstance;
    %AccessCode
        // In this contrived example the C++ library we are wrapping defines
        // klassInstance as Klass ** (which SIP doesn't support) so we
        // explicitly dereference it.
        if (klassInstance && *klassInstance)
            return *klassInstance;

        // This will get converted to None.
        return 0;
    %End


%CModule
--------

.. parsed-literal::

    %CModule *name* [*version*]

This directive is used to identify that the library being wrapped is a C
library and to define the name of the module and it's optional version number.

See the `%Module`_ directive for an explanation of the version number.

For example::

    %CModule dbus 1


%ConvertFromTypeCode
--------------------

.. parsed-literal::

    %ConvertFromTypeCode
        *code*
    %End

This directive is used as part of the `%MappedType`_ directive to specify the
handwritten code that converts an instance of a mapped type to a Python
object.

The following variables are made available to the handwritten code:

*type* \*sipCpp
    This is a pointer to the instance of the mapped type to be converted.  It
    may be zero.

The handwritten code must explicitly return a ``PyObject *``.  If there was an
error then a Python exception must be raised and ``NULL`` returned.

The following example converts a ``QValueList<int>`` instance to a Python
list of numbers::

    %ConvertFromTypeCode
        // Handle the case where the C++ instance is 0.
        if (!sipCpp)
            return PyList_New(0);

        PyObject *l;

        // Create the Python list of the correct length.
        if ((l = PyList_New(sipCpp -> count())) == NULL)
            return NULL;

        // Go through each int in the C++ instance and convert it to a number.
        for (uint i = 0; i < sipCpp -> count(); ++i)
            if (PyList_SetItem(l, i, PyInt_FromLong((*sipCpp)[i])) < 0)
            {
                // There was an error so garbage collect the Python list.
                Py_DECREF(l);
                return NULL;
            }

        // Return the Python list.
        return l;
    %End


%ConvertToSubClassCode
----------------------

.. parsed-literal::

    %ConvertToSubClassCode
        *code*
    %End

When SIP needs to wrap a C++ class instance it first checks to make sure it
hasn't already done so.  If it has then it just returns a new reference to the
corresponding Python object.  Otherwise it creates a new Python object of the
appropriate type.  In C++ a function may be defined to returned an instance of
a certain class, but can often return a sub-class instead.

This directive is used to specify handwritten code that exploits any available
real-time type information (RTTI) to see if there is a more specific Python
type that can be used when wrapping the C++ instance.  The RTTI may be
provided by the compiler or by the C++ instance itself.

The directive is included in the specification of one of the classes that the
handwritten code handles the type conversion for.  It doesn't matter which
one, but a sensible choice would be the one at the root of that class
hierarchy in the module.

Note that if a class hierarchy extends over a number of modules then this
directive should be used in each of those modules to handle the part of the
hierarchy defined in that module.  SIP will ensure that the different pieces
of code are called in the right order to determine the most specific Python
type to use.

The following variables are made available to the handwritten code:

*type* \*sipCpp
    This is a pointer to the C++ class instance.

sipWrapperType \*sipClass
    The handwritten code must set this to the SIP generated Python type object
    that corresponds to the class instance.  (The type object for class
    ``Klass`` is ``sipClass_Klass``.)  If the RTTI of the class instance isn't
    recognised then ``sipClass`` must be set to ``NULL``.

The handwritten code must not explicitly return.

The following example shows the sub-class conversion code for ``QEvent`` based
class hierarchy in PyQt::

    class QEvent
    {
    %ConvertToSubClassCode
        // QEvent sub-classes provide a unique type ID.
        switch (sipCpp -> type())
        {
        case QEvent::Timer:
            sipClass = sipClass_QTimerEvent;
            break;

        case QEvent::KeyPress:
        case QEvent::KeyRelease:
            sipClass = sipClass_QKeyEvent;
            break;

        // Skip the remaining event types the keep the example short.

        default:
            // We don't recognise the type.
            sipClass = NULL;
        }
    %End

        // The rest of the class specification.

    };

The SIP API includes the `sipMapIntToClass()`_ and `sipMapStringToClass()`_
functions that convert integer and string based RTTI to Python type objects
based on ordered lookup tables.


%ConvertToTypeCode
------------------

.. parsed-literal::

    %ConvertToTypeCode
        *code*
    %End

This directive is used to specify the handwritten code that converts a Python
object to a mapped type instance.  It is used as part of the `%MappedType`_
directive and as part of a class specification.  The code is also called to
determine if the Python object is of the correct type prior to conversion.

When used as part of a class specification is can automatically convert
additional types of Python object.  For example, PyQt uses it in the
specification of the ``QString`` class to allow Python string objects and
Unicode objects to be used wherever ``QString`` instances are expected.

The following variables are made available to the handwritten code:

int \*sipIsErr
    If this is ``NULL`` then the code is being asked to check the type of the
    Python object.  The check must not have any side effects.  Otherwise the
    code is being asked to convert the Python object and a non-zero value
    should be returned through this pointer if an error occurred during the
    conversion.

PyObject \*sipPy
    This is the Python object to be converted.

*type* \*\*sipCppPtr
    This is a pointer through which the address of the mapped type instance (or
    zero if appropriate) is returned.  Its value is undefined if ``sipIsErr``
    is ``NULL``.

The handwritten code must explicitly return an ``int`` that is either zero or
non-zero.  Its meaning depends on the value of ``sipIsErr``.

If ``sipIsErr`` is ``NULL`` then a non-zero value is returned if the Python
object has a type that can be converted to the mapped type.  Otherwise zero is
returned.

If ``sipIsErr`` is not ``NULL`` then a non-zero value is returned if the
mapped type instance returned through ``sipCppPtr`` was created on the heap.
Otherwise zero is returned.

The following example converts a Python list of numbers to a
``QValueList<int>`` instance::

    %ConvertToTypeCode
        // See if we are just being asked to check the type of the Python
        // object.
        if (sipIsErr == NULL)
            return PyList_Check(sipPy);

        // We map None to a 0 pointer.
        if (sipPy == Py_None)
        {
            *sipCppPtr = 0;

            // There is nothing on the heap.
            return 0;
        }

        // Create the instance on the heap.
        QValueList<int> *qvl = new QValueList<int>;

        PyErr_Clear();

        for (int i = 0; i < PyList_GET_SIZE(sipPy); ++i)
        {
            qvl -> append(PyInt_AsLong(PyList_GET_ITEM(sipPy, i)));

            if (PyErr_Occurred() != NULL)
            {
                // Tidy up.
                delete qvl;

                // Set the error flag.
                *sipIsErr = 1;

                // There is nothing on the heap.
                return 0;
            }
        }

        // Return the instance on the heap.
        *sipCppPtr = qvl;

        // The result is a pointer to an instance on the heap.
        return 1;
    %End


%Copying
--------

.. parsed-literal::

    %Copying
        *text*
    %End

This directive is used to specify some arbitrary text that will be included at
the start of all source files generated by SIP.  It is normally used to
include copyright and licensing terms.

For example::

    %Copying
    Copyright (c) 2004 Riverbank Computing Limited
    %End


%Doc
----

.. parsed-literal::

    %Doc
        *text*
    %End

This directive is used to specify some arbitrary text that will be extracted
by SIP when the ``-d`` command line option is used.  The directive can be
specified any number of times and SIP will concatenate all the separate pieces
of text in the order that it sees them.

Documentation that is specified using this directive is local to the module in
which it appears.  It is ignored by modules that `%Import`_ it.  Use the
`%ExportedDoc`_ directive for documentation that should be included by all
modules that `%Import`_ this one.

For example::

    %Doc
    <h1>An Example</h1>
    <p>
    This fragment of documentation is HTML and is local to the module in
    which it is defined.
    </p>
    %End


%End
----

This isn't a directive in itself, but is used to terminate a number of
directives that allow a block of handwritten code or text to be specified.


%ExportedDoc
------------

.. parsed-literal::

    %ExportedDoc
        *text*
    %End

This directive is used to specify some arbitrary text that will be extracted
by SIP when the ``-d`` command line option is used.  The directive can be
specified any number of times and SIP will concatenate all the separate pieces
of text in the order that it sees them.

Documentation that is specified using this directive will also be included by
modules that `%Import`_ it.

For example::

    %ExportedDoc
    ==========
    An Example
    ==========
    
    This fragment of documentation is reStructuredText and will appear in the
    module in which it is defined and all modules that %Import it.
    %End


%Feature
--------

.. parsed-literal::

    %Feature *name*

This directive is used to declare a feature.  Features (along with
`%Platforms`_ and `%Timeline`_) are used by the `%If`_ directive to control
whether or not parts of a specification are processed or ignored.

Features are mutually independent of each other - any combination of features
may be enabled or disable.  By default all features are enabled.  The SIP
``-x`` command line option is used to disable a feature.

If a feature is enabled then SIP will automatically generate a corresponding C
preprocessor symbol for use by handwritten code.  The symbol is the name of
the feature prefixed by ``SIP_FEATURE_``.

For example::

    %Feature FOO_SUPPORT

    %If (FOO_SUPPORT)
    void foo();
    %End


%If
---

.. parsed-literal::

    %If (*expression*)
        *specification*
    %End

where

.. parsed-literal::

    *expression* ::= [*ored-qualifiers* | *range*]

    *ored-qualifiers* ::= [*qualifier* | *qualifier* ``||`` *ored-qualifiers*]

    *qualifier* ::= [``!``] [*feature* | *platform*]

    *range* ::= [*version*] ``-`` [*version*]

This directive is used in conjunction with features (see `%Feature`_),
platforms (see `%Platforms`_) and versions (see `%Timeline`_) to control
whether or not parts of a specification are processed or not.

A *range* of versions means all versions starting with the lower bound up to
but excluding the upper bound.  If the lower bound is omitted then it is
interpreted as being before the earliest version.  If the upper bound is
omitted then it is interpreted as being after the latest version.

For example::

    %Feature SUPPORT_FOO
    %Platforms {WIN32_PLATFORM POSIX_PLATFORM MACOS_PLATFORM}
    %Timeline {V1_0 V1_1 V2_0 V3_0}

    %If (!SUPPORT_FOO)
        // Process this if the SUPPORT_FOO feature is disabled.
    %End

    %If (POSIX_PLATFORM || MACOS_PLATFORM)
        // Process this if either the POSIX_PLATFORM or MACOS_PLATFORM
        // platforms are enabled.
    %End

    %If (V1_0 - V2_0)
        // Process this if either V1_0 or V1_1 is enabled.
    %End

    %If (V2_0 - )
        // Process this if either V2_0 or V3_0 is enabled.
    %End

    %If ( - )
        // Always process this.
    %End

Note that this directive is not implemented as a preprocessor.  Only the
following parts of a specification are affected by it:

    - ``class``
    - `%ConvertFromTypeCode`_
    - `%ConvertToSubClassCode`_
    - `%ConvertToTypeCode`_
    - ``enum``
    - functions
    - `%If`_
    - `%MappedType`_
    - `%MethodCode`_
    - `%ModuleCode`_
    - `%ModuleHeaderCode`_
    - ``namespace``
    - ``struct``
    - ``typedef``
    - `%TypeCode`_
    - `%TypeHeaderCode`_
    - variables
    - `%VirtualCatcherCode`_

Also note that the only way to specify the logical and of qualifiers is to use
nested `%If`_ directives.


%Import
-------

.. parsed-literal::

    %Import *filename*

This directive is used to import the specification of another module.  This is
needed if the current module makes use of any types defined in the imported
module, e.g. as an argument to a function, or to sub-class.

If *filename* cannot be opened then SIP prepends *filename* with the name of
the directory containing the current specification file (i.e. the one
containing the `%Import`_ directive) and tries again.  If this also fails then
SIP prepends *filename* with each of the directories, in turn, specified by
the ``-I`` command line option.

For example::

    %Import qt/qtmod.sip


%Include
--------

.. parsed-literal::

    %Include *filename*

This directive is used to include contents of another file as part of the
specification of the current module.  It is the equivalent of the C
preprocessor's ``#include`` directive and is used to structure a large module
specification into manageable pieces.

`%Include`_ follows the same search process as `%Import`_ when trying to open
*filename*.

For example::

    %Include qwidget.sip


%License
--------

.. parsed-literal::

    %License /*license-annotations*/

This directive is used to specify the contents of an optional license
dictionary.  The license dictionary is called ``__license__`` and is stored in
the module dictionary.  The elements of the dictionary are specified using the
Licensee_, Signature_, Timestamp_ and Type_ annotations.  Only the Type_
annotation is compulsory.

Note that this directive isn't an attempt to impose any licensing restrictions
on a module.  It is simply a method for easily embedding licensing information
in a module so that it is accessible to Python scripts.

For example::

    %License /Type="GPL"/


%MappedType
-----------

.. parsed-literal::

    %MappedType *type*
    {
        [*header-code*]
        [*convert-to-code*]
        [*convert-from-code*]
    }

This directive is used to define an automatic mapping between a C or C++ type
and a Python type.  The C/C++ *type* being mapped must be either a structure,
a class, or a template.  Mapped types are the only way SIP supports templates.

*header-code* is the `%TypeHeaderCode`_ used to specify the library interface
to the type being mapped.

*convert-to-code* is the `%ConvertToTypeCode`_ used to specify the handwritten
code that converts a Python object to an instance of the mapped type.

*convert-from-code* is the `%ConvertFromTypeCode`_ used to specify the
handwritten code that converts an instance of the mapped type to a Python
object.

For example::

    %MappedType QValueList<int>
    {
    %TypeHeaderCode
    // Include the library interface to the type being mapped.
    #include <qvaluelist.h>
    %End

    %ConvertToTypeCode
        // See the %ConvertToTypeCode example for the code that converts a
        // Python list of numbers to a QValueList<int> instance.
    %End

    %ConvertFromTypeCode
        // See the %ConvertFromTypeCode example for the code that converts a
        // QValueList<int> instance to a Python list of numbers.
    %End
    }

In this example we can use ``QValueList<int>`` throughout the module's
specification files (and in any module that imports this one).  The generated
code will automatically map this to and from a Python list of numbers when
appropriate.


%MethodCode
-----------

.. parsed-literal::

    %MethodCode
        *code*
    %End

This directive is used as part of the specification of a global function, class
method, operator, constructor or destructor to specify handwritten code that
replaces the normally generated call to the function being wrapped.  It is
usually used to handle argument types and results that SIP cannot deal with
automatically.

The specified code is embedded in-line after the function's arguments have
been successfully converted from Python objects to their C or C++ equivalents.
The specified code must not include any ``return`` statements.

The the context of a destructor the specified code is embedded in-line in the
Python type's deallocation function.

The specified code must also handle the Python Global Interpreter Lock (GIL).
If compatibility with `SIP v3.x`_ is required then the GIL must be released
immediately before the C++ call and reacquired immediately afterwards as shown
in this example fragment::

    Py_BEGIN_ALLOW_THREADS
    sipCpp -> foo();
    Py_END_ALLOW_THREADS

If compatibility with `SIP v3.x`_ is not required then this is optional but
should be done if the C++ function might block the current thread or take a
significant amount of time to execute.  (See the ReleaseGIL_ annotation.)

The following variables are made available to the handwritten code:

*type* a0
    There is a variable for each argument of the Python signature (excluding
    any ``self`` argument) named ``a0``, ``a1``, etc.  The *type* of the
    variable is the same as the type defined in the specification with the
    following exceptions:

    - if the argument is only used to return a value (e.g. it is an ``int *``
      without an In_ annotation) then the type has one less level of
      indirection (e.g. it will be an ``int``)
    - if the argument is a structure or class (or a reference or a pointer to a
      structure or class) then *type* will always be a pointer to the structure
      or class.

    Note that handwritten code for destructors never has any arguments.

PyObject \*a0Wrapper
    This variable is made available only if the corresponding argument wraps a
    C structure or C++ class instance and the GetWrapper_ annotation is
    specified.  The variable is a pointer to the Python object that wraps the
    argument.

*type* \*sipCpp
    If the directive is used in the context of a class constructor then this
    must be set by the handwritten code to the constructed instance.  In any
    other class context then this is a pointer to the class instance.  Its
    *type* is a pointer to the structure or class.

int sipIsErr
    The handwritten code should set this to a non-zero value, and raise an
    appropriate Python exception, if an error is detected.

    ``sipIsErr`` is not provided for destructors.

*type* sipRes
    The handwritten code should set this to the result to be returned.  The
    *type* of the variable is the same as the type defined in the Python
    signature in the specification with the following exception:

    - if the argument is a structure or class (or a reference or a pointer to a
      structure or class) then *type* will always be a pointer to the structure
      or class.

    ``sipRes`` is not provided for inplace operators (e.g. ``+=`` or
    ``__imul__``) as their results are handled automatically, nor for class
    constructors.

PyObject \*sipSelf
    If the directive is used in the context of a class method then this is the
    Python object that wraps the the structure or class instance,
    i.e. ``self``.

For example::

    class Klass
    {
    public:
        int foo(SIP_PYTUPLE);
    %MethodCode
            // The C++ API takes a 2 element array of integers but passing a
            // two element tuple is more Pythonic.

            int iarr[2];

            if (PyArg_ParseTuple(a0, "ii", &iarr[0], &iarr[1]))
            {
                Py_BEGIN_ALLOW_THREADS
                sipRes = sipCpp -> Klass::foo(iarr);
                Py_END_ALLOW_THREADS
            }
            else
            {
                // PyArg_ParseTuple() will have raised the exception.
                sipIsErr = 1;
            }
    %End
    };

Note the use of the fully scoped method name in the example (i.e.
``Klass::foo()`` rather than just ``foo()``).  This is required for virtual
methods [#]_ in order to avoid virtual call loops, but is a good habit to get
into for all public methods.

If a method is in the ``protected`` section of a C++ class then the call
should instead be::

    sipRes = sipCpp -> sipProtect_foo(iarr);

.. [#] See `%VirtualCatcherCode`_ for a description of how SIP generated code
       handles the reimplementation of C++ virtual methods in Python.


%Module
-------

.. parsed-literal::

    %Module *name* [*version*]

This directive is used to identify that the library being wrapped is a C++
library and to define the name of the module and it's optional version number.

The optional version number is useful if you (or others) might create other
modules that build on this module, i.e. if another module might `%Import`_
this module.  Under the covers, a module exports an API that is used by modules
that `%Import`_ it and the API is given a version number.  A module built on
that module knows the version number of the API that it is expecting.  If,
when the modules are imported at run-time, the version numbers do not match
then a Python exception is raised.  The dependent module must then be re-built
using the correct specification files for the base module.

The version number should be incremented whenever a module is changed.  Some
changes don't affect the exported API, but it is good practice to change the
version number anyway.

For example::

    %Module qt 5


%ModuleCode
-----------

.. parsed-literal::

    %ModuleCode
        *code*
    %End

This directive is used to specify handwritten code, typically the
implementations of utility functions, that can be called by other handwritten
code in the module.

For example::

    %ModuleCode
    // Print an object on stderr for debugging purposes.
    void dump_object(PyObject *o)
    {
        PyObject_Print(o, stderr, 0);
        fprintf(stderr, "\n");
    }
    %End

See also `%ModuleHeaderCode`_.


%ModuleHeaderCode
-----------------

.. parsed-literal::

    %ModuleHeaderCode
        *code*
    %End

This directive is used to specify handwritten code, typically the declarations
of utility functions, that is placed in a header file that is included by all
generated code.

For example::

    %ModuleHeaderCode
    void dump_object(PyObject *o);
    %End

See also `%ModuleCode`_.


%OptionalInclude
----------------

.. parsed-literal::

    %OptionalInclude *filename*

This directive is identical to the `%Include`_ directive except that SIP
silently continues processing if *filename* could not be opened.

For example::

    %OptionalInclude license.sip


%Platforms
----------

.. parsed-literal::

    %Platforms {*name* *name* ...}

This directive is used to declare a set of platforms.  Platforms (along with
`%Feature`_ and `%Timeline`_) are used by the `%If`_ directive to control
whether or not parts of a specification are processed or ignored.

Platforms are mutually exclusive - only one platform can be enabled at a time.
By default all platforms are disabled.  The SIP ``-t`` command line option is
used to enable a platform.

For example::

    %Platforms {WIN32_PLATFORM POSIX_PLATFORM MACOS_PLATFORM}

    %If (WIN32_PLATFORM)
    void undocumented();
    %End

    %If (POSIX_PLATFORM)
    void documented();
    %End


%PostInitialisationCode
-----------------------

.. parsed-literal::

    %PostInitialisationCode
        *code*
    %End

This directive is used to specify handwritten code that is embedded in-line
at the very end of the generated module initialisation code.

For example::

    %PostInitialisationCode
        // The code will be executed when the module is first imported and
        // after all other initialisation has been completed.
    %End


%Timeline
---------

.. parsed-literal::

    %Timeline {*name* *name* ...}

This directive is used to declare a set of versions released over a period of
time.  Versions (along with `%Feature`_ and `%Platforms`_) are used by the
`%If`_ directive to control whether or not parts of a specification are
processed or ignored.

Versions are mutually exclusive - only one version can be enabled at a time.
By default all versions are disabled.  The SIP ``-t`` command line option is
used to enable a version.

For example::

    %Timeline {V1_0 V1_1 V2_0 V3_0}

    %If (V1_0 - V2_0)
    void foo();
    %End

    %If (V2_0 -)
    void foo(int = 0);
    %End


%TypeCode
---------

.. parsed-literal::

    %TypeCode
        *code*
    %End

This directive is used as part of the specification of a C structure or a C++
class to specify handwritten code, typically the implementations of utility
functions, that can be called by other handwritten code in the structure or
class.

For example::

    class Klass
    {
    %TypeCode
    // Print an instance on stderr for debugging purposes.
    static void dump_klass(const Klass *k)
    {
        fprintf(stderr,"Klass %s at %p\n", k -> name(), k);
    }
    %End

        // The rest of the class specification.

    };

Because the scope of the code is normally within the generated file that
implements the type, any utility functions would normally be declared
``static``.  However a naming convention should still be adopted to prevent
clashes of function names within a module in case the SIP ``-j`` command line
option is used.


%TypeHeaderCode
---------------

.. parsed-literal::

    %TypeHeaderCode
        *code*
    %End

This directive is used to specify handwritten code that defines the interface
to a C or C++ type being wrapped, either a structure, a class, or a template.
It is used within a class definition or a `%MappedType`_ directive.

Normally *code* will be a pre-processor ``#include`` statement.

For example::

    // Wrap the Klass class.
    class Klass
    {
    %TypeHeaderCode
    #include <klass.h>
    %End

        // The rest of the class specification.
    };


%VirtualCatcherCode
-------------------

.. parsed-literal::

    %VirtualCatcherCode
        *code*
    %End

For most classes there are corresponding `generated derived classes`_ that
contain reimplementations of the class's virtual methods.  These methods (which
SIP calls catchers) determine if there is a corresponding Python
reimplementation and call it if so.  If there is no Python reimplementation
then the method in the original class is called instead.

This directive is used to specify handwritten code that replaces the normally
generated call to the Python reimplementation and the handling of any returned
results.  It is usually used to handle argument types and results that SIP
cannot deal with automatically.

This directive can also be used in the context of a class destructor to
specify handwritten code that is embedded in-line in the internal derived
class's destructor.

In the context of a method the Python Global Interpreter Lock (GIL) is
automatically acquired before the specified code is executed and automatically
released afterwards.

In the context of a destructor the specified code must handle the GIL.  The
GIL must be acquired before any calls to the Python API and released after the
last call as shown in this example fragment::

    SIP_BLOCK_THREADS
    Py_DECREF(obj);
    SIP_UNBLOCK_THREADS

The following variables are made available to the handwritten code in the
context of a method:

*type* a0
    There is a variable for each argument of the C++ signature named ``a0``,
    ``a1``, etc.  The *type* of the variable is the same as the type defined in
    the specification.

int sipIsErr
    The handwritten code should set this to a non-zero value, and raise an
    appropriate Python exception, if an error is detected.

PyObject \*sipMethod
    This object is the Python reimplementation of the virtual C++ method.  It
    is normally passed to `sipCallMethod()`_.

*type* sipRes
    The handwritten code should set this to the result to be returned.  The
    *type* of the variable is the same as the type defined in the C++ signature
    in the specification.

No variables are made available in the context of a destructor.

For example::

    class Klass
    {
    public:
        virtual int foo(SIP_PYTUPLE) [int (int *)];
    %MethodCode
            // The C++ API takes a 2 element array of integers but passing a
            // two element tuple is more Pythonic.

            int iarr[2];

            if (PyArg_ParseTuple(a0, "ii", &iarr[0], &iarr[1]))
            {
                Py_BEGIN_ALLOW_THREADS
                sipRes = sipCpp -> Klass::foo(iarr);
                Py_END_ALLOW_THREADS
            }
            else
            {
                // PyArg_ParseTuple() will have raised the exception.
                sipIsErr = 1;
            }
    %End
    %VirtualCatcherCode
            // Convert the 2 element array of integers to the two element
            // tuple.

            PyObject *result;

            result = sipCallMethod(&sipIsErr, sipMethod, "ii", a0[0], a0[1]);

            if (result != NULL)
            {
                // Convert the result to the C++ type.
                sipParseResult(&sipIsErr, sipMethod, result, "i", &sipRes);

                Py_DECREF(result);
            }
    %End
    };


SIP Annotations
===============

In this section we describe each of the annotations that can be used in
specification files.

Annotations can either be argument annotations, class annotations, function
annotations, or license annotations depending on the context in which they can
be used.

Annotations are placed between forward slashes (``/``).  Multiple annotations
are comma separated within the slashes.

Annotations have a type and, possibly, a value.  The type determines the
format of the value.  The name of an annotation and its value are separated by
``=``.

Annotations can have one of the following types:

boolean
    This type of annotation has no value and is implicitly true.

name
    The value is a name that is compatible with a C/C++ identifier.  In some
    cases the value is optional.

string
    The value is a double quoted string.

The following example shows argument and function annotations::

    void exec(QWidget * /Transfer/) /ReleaseGIL, PyName=call_exec/;

Note that the current version of SIP does not complain about unknown
annotations, or annotations used out of their correct context.


Argument Annotations
--------------------

AllowNone
*********

This boolean annotation specifies that the value of the corresponding argument
(which should be either SIP_PYCALLABLE_, SIP_PYDICT_, SIP_PYLIST_,
SIP_PYSLICE_ or SIP_PYTUPLE_) may be ``None``.


Array
*****

This boolean annotation specifies that the corresponding argument (which
should be either ``char *`` or ``unsigned char *``) refers to an array
rather than a ``'\0'`` terminated string.  There must be a corresponding
argument with the ArraySize_ annotation specified.  The annotation may only be
specified once in a list of arguments.


ArraySize
*********

This boolean annotation specifies that the corresponding argument (which
should be either ``short``, ``unsigned short``, ``int``, ``unsigned``,
``long`` or ``unsigned long``) refers to the size of an array.  There must be
a corresponding argument with the Array_ annotation specified.  The annotation
may only be specified once in a list of arguments.


Constrained
***********

Python will automatically convert between certain compatible types.  For
example, if a floating pointer number is expected and an integer supplied,
then the integer will be converted appropriately.  This can cause problems
when wrapping C or C++ functions with similar signatures.  For example::

    // The wrapper for this function will also accept an integer argument
    // which Python will automatically convert to a floating point number.
    void foo(double);

    // The wrapper for this function will never get used.
    void foo(int);

This boolean annotation specifies that the corresponding argument (which
should be either ``int``, ``float`` or ``double``) must match the type without
any automatic conversions.  The following example gets around the above
problem::

    // The wrapper for this function will only accept floating point numbers.
    void foo(double /Constrained/);

    // The wrapper for this function will be used for anything that Python can
    // convert to an integer, except for floating point numbers.
    void foo(int);


GetWrapper
**********

This boolean annotation is only ever used in conjunction with handwritten code
specified with the `%MethodCode`_ directive.  It causes an extra variable to
be generated for the corresponding argument (which should be a wrapped C
structure or C++ class instance) which is a pointer to the Python object that
wraps the argument.

See the `%MethodCode`_ directive for more detail.


In
**

This boolean annotation is used to specify that the corresponding argument
(which should be a pointer type) is used to pass a value to the function.

For pointers to wrapped C structures or C++ class instances, ``char *`` and
``unsigned char *`` then this annotation is assumed unless the Out_ annotation
is specified.

For pointers to other types then this annotation must be explicitly specified
if required.  The argument will be dereferenced to obtain the actual value.

Both In_ and Out_ may be specified for the same argument.


Out
***

This boolean annotation is used to specify that the corresponding argument
(which should be a pointer type) is used by the function to return a value as
an element of a tuple.

For pointers to wrapped C structures or C++ class instances, ``char *`` and
``unsigned char *`` then this annotation must be explicitly specified if
required.

For pointers to other types then this annotation is assumed unless the In_
annotation is specified.

Both In_ and Out_ may be specified for the same argument.


Transfer
********

This boolean annotation is used to specify that ownership of the corresponding
argument (which should be a wrapped C structure or C++ class instance) is
transferred from Python to C++.

See `Ownership of Objects`_ for more detail.


TransferBack
************

This boolean annotation is used to specify that ownership of the corresponding
argument (which should be a wrapped C structure or C++ class instance) is
transferred back to Python from C++.

Note that this can also be used as a function annotation.  In this context
ownership of the value returned by the function is transferred back to Python.

See `Ownership of Objects`_ for more detail.


TransferThis
************

This boolean annotation is only used in C++ constructors.  It specifies that
ownership of the instance being constructed is transferred from Python to C++
if the corresponding argument (which should be a wrapped C structure or C++
class instance) is not ``None``.

See `Ownership of Objects`_ for more detail.


Class Annotations
-----------------

Abstract
********

SIP needs to know if a class is abstract and cannot be instanciated.  If a
class is fully specified then SIP has enough information to know if it is or
not.  Often it is convenient not to specify a class fully.  This boolean
annotation is used to explicitly specify that the class is abstract.


Function Annotations
--------------------

AutoGen
*******

This optional name annotation is used with class methods to specify that the
method be automatically included in all sub-classes.  The value is the name of
a feature (specified using the `%Feature`_ directive) which must be enabled
for the method to be generated.


Default
*******

This boolean annotation is only used with C++ constructors.  Sometimes SIP
needs to create a class instance.  By default it uses a constructor with no
compulsory arguments if one is specified.  (SIP will automatically generate a
constructor with no arguments if no constructors are specified.)  This
annotation is used to explicitly specify which constructor to use.  Zero is
passed as the value of any arguments to the constructor.


Factory
*******

This boolean annotation specifies that the value returned by the function
(which should be a wrapped C structure or C++ class instance) is owned by
Python (see `Ownership of Objects`_).  Normally returned values (unless they
are new references to already wrapped values) are owned by C++.


NewThread
*********

This boolean annotation specifies that the function will create a new thread.


Numeric
*******

This boolean annotation specifies that the operator should be interpreted as a
numeric operator rather than a sequence operator.  Python uses the ``+``
operator for adding numbers and concatanating sequences, and the ``*`` operator
for multiplying numbers and repeating sequences.  SIP tries to work out which
is meant by looking at other operators that have been defined for the type.
If it finds either ``-``, ``-=``, ``/``, ``/=``, ``%`` or ``%=`` defined then
it assumes that ``+``, ``+=``, ``*`` and ``*=`` should be numeric operators.
Otherwise, if it finds either ``[]``, ``__getitem__()``, ``__setitem__()`` or
``__delitem__()`` defined then it assumes that they should be sequence
operators.  This annotation is used to force SIP to treat the operator as
numeric.


PostHook
********

This name annotation is used to specify the name of a Python builtin that is
called immediately after call to the underlying C or C++ function or any
handwritten code.  The builtin is not called if an error occurred.  It is
primarily used to integrate with debuggers.


PreHook
*******

This name annotation is used to specify the name of a Python builtin that is
called immediately after the function's arguments have been successfully
parsed and before the call to the underlying C or C++ function or any
handwritten code.  It is primarily used to integrate with debuggers.


PyName
******

Python keywords cannot be used as Python function or method names.  This name
annotation specifies an alternative name for the function being wrapped which
is used when calling the function from Python.


ReleaseGIL
**********

This boolean annotation specifies that the Python Global Interpreter Lock
(GIL) is automatically released before the call to the underlying C or C++
function and reacquired afterwards.  It should be used for functions that
might block or take a significant amount of time to execute.


License Annotations
-------------------

Licensee
********

This optional string annotation specifies the license's licensee.  No
restrictions are placed on the contents of the string.

See the `%License`_ directive.


Signature
*********

This optional string annotation specifies the license's signature.  No
restrictions are placed on the contents of the string.

See the `%License`_ directive.


Timestamp
*********

This optional string annotation specifies the license's timestamp.  No
restrictions are placed on the contents of the string.

See the `%License`_ directive.


Type
****

This string annotation specifies the license's type.  No restrictions are
placed on the contents of the string.

See the `%License`_ directive.


SIP API for Handwritten Code
============================

In this section we describe the API that can be used by handwritten code in
specification files.


SIP_API_MAJOR_NR
----------------

This is a C preprocessor symbol that defines the major number of the SIP API.
Its value is a number.  There is no direct relationship between this and the
SIP version number.


SIP_API_MINOR_NR
----------------

This is a C preprocessor symbol that defines the minor number of the SIP API.
Its value is a number.  There is no direct relationship between this and the
SIP version number.


SIP_BLOCK_THREADS
-----------------

This is a C preprocessor macro that will make sure the Python Global
Interpreter Lock (GIL) is acquired.  Python API calls must only be made when
the GIL has been acquired.  There must be a corresponding
`SIP_UNBLOCK_THREADS`_ at the same lexical scope.


SIP_BUILD
---------

This is a C preprocessor symbol that defines a unique SIP build identifier
represented as a string.


SIP_UNBLOCK_THREADS
-------------------

This is a C preprocessor macro that will restore the Python Global Interpreter
Lock (GIL) to the state it was prior to the corresponding `SIP_BLOCK_THREADS`_.


SIP_VERSION
-----------

This is a C preprocessor symbol that defines the SIP version number
represented as a 3 part hexadecimal number (e.g. v4.0.0 is represented as
``0x040000``).


SIP_VERSION_STR
---------------

This is a C preprocessor symbol that defines the SIP version number
represented as a string.  For development snapshots it will start with
``snapshot-``.


sipBadCatcherResult()
---------------------

void sipBadCatcherResult(PyObject \*method)
    This is raises a Python exception when the result of a Python
    reimplementation of a C++ method doesn't have the expected type.  It is
    normally called by handwritten code specified with the
    `%VirtualCatcherCode`_ directive.  *method* is the Python method and would
    normally be the supplied ``sipMethod``.


sipBadLengthForSlice()
----------------------

void sipBadLengthForSlice(int seqlen, int slicelen)
    This raises a Python exception when the length of a slice object is
    inappropriate for a sequence-like object.  It is normally called by
    handwritten code specified for ``__setitem__()`` methods.  *seqlen* is the
    length of the sequence.  *slicelen* is the length of the slice.


sipBuildResult()
----------------

PyObject \*sipBuildResult(int \*iserr, char \*format, ...)
    This creates a Python object based on a format string and associated
    values in a similar way to the Python ``Py_BuildValue()`` function.  If
    there was an error then ``NULL`` is returned and a Python exception is
    raised.  If *iserr* is not ``NULL`` then the location it points to is set
    to a non-zero value.  *format* is the string of format characters.

    If *format* begins and ends with parentheses then a tuple of objects is
    created.  If *format* contains more than one format character then
    parentheses must be specified.

    In the following description the first letter is the format character, the
    entry in parentheses is the Python object type that the format character
    will create, and the entry in brackets are the types of the C/C++ values
    to be passed. 

    ``a`` (string) [char \*, int]
        Convert a C/C++ character array and its length to a Python string.  If
        the character array is ``NULL`` then the length is ignored and the
        result is ``Py_None``.

    ``b`` (boolean) [int]
        Convert a C/C++ ``int`` to a Python boolean.

    ``c`` (string) [char]
        Convert a C/C++ ``char`` to a Python string.

    ``d`` (float) [double]
        Convert a C/C++ ``double`` to a Python floating point number.

    ``e`` (integer) [enum]
        Convert a C/C++ ``enum`` to a Python integer.

    ``f`` (float) [float]
        Convert a C/C++ ``float`` to a Python floating point number.

    ``h`` (integer) [short]
        Convert a C/C++ ``short`` to a Python integer.

    ``i`` (integer) [int]
        Convert a C/C++ ``int`` to a Python integer.

    ``l`` (integer) [long]
        Convert a C/C++ ``long`` to a Python integer.

    ``s`` (string) [char \*]
        Convert a C/C++ ``'\0'`` terminated string to a Python string.  If the
        string pointer is ``NULL`` then the result is ``Py_None``.

    ``M`` (wrapped instance) [*type* \*, sipWrapperType \*]
        Convert a C structure or a C++ class instance to a Python class
        instance object.  If the structure or class instance has already been
        wrapped then the result is a new reference to the existing class
        instance object.  The Python class is influenced by any applicable
        `%ConvertToSubClassCode`_ code.

    ``N`` (wrapped instance) [*type* \*, sipWrapperType \*]
        Convert a C structure or a C++ class instance to a Python class
        instance object.  This should not be used if the structure or class
        instance might already have been wrapped.  The Python class is
        influenced by any applicable `%ConvertToSubClassCode`_ code.  It is
        recommended that handwritten code use the ``M`` format character
        instead.

    ``O`` (wrapped instance) [*type* \*, sipWrapperType \*]
        Convert a C structure or a C++ class instance to a Python class
        instance object.  If the structure or class instance has already been
        wrapped then the result is a new reference to the existing class
        instance object.  It is recommended that handwritten code use the
        ``M`` format character instead.

    ``P`` (wrapped instance) [*type* \*, sipWrapperType \*]
        Convert a C structure or a C++ class instance to a Python class
        instance object.  This should not be used if the structure or class
        instance might already have been wrapped.  It is recommended that
        handwritten code use the ``M`` format character instead.

    ``R`` (object) [PyObject \*]
        The result is value passed without any conversions.  The reference
        count is unaffected, i.e. a reference is taken.

    ``S`` (object) [PyObject \*]
        The result is value passed without any conversions.  The reference
        count is incremented.

    ``T`` (object) [void \*, PyObject \*(\*)(void \*cppptr)]
        Convert a C structure or a C++ class instance to a Python object using
        a convertor function.  See `Generated Type Convertors`_.

    ``V`` (sip.voidptr) [void \*]
        Convert a C/C++ ``void *`` Python ``sip.voidptr`` object.


sipCallMethod()
---------------

PyObject \*sipCallMethod(int \*iserr, PyObject \*method, char \*format, ...)
    This calls a Python method passing a tuple of arguments based on a format
    string and associated values in a similar way to the Python
    ``PyObject_CallObject()`` function.  If there was an error then ``NULL`` is
    returned and a Python exception is raised.  If *iserr* is not ``NULL``
    then the location it points to is set to a non-zero value.  *method* is the
    Python bound method to call.  *format* is the string of format characters
    (see `sipBuildResult()`_).

    This is normally called by handwritten code specified with the
    `%VirtualCatcherCode`_ directive with *method* being the supplied
    ``sipMethod``.


sipClassName()
--------------

PyObject \*sipClassName(PyObject \*obj)
    This returns the class name of a wrapped instance as a Python string.  It
    comes with a reference.


sipConnectRx()
--------------

PyObject \*sipConnectRx(PyObject \*sender, const char \*signal, PyObject \*receiver, const char \*slot)
    This connects a signal to a signal or slot and returns ``Py_True`` if the
    signal was connected or ``Py_False`` if not.  If there was some other
    error then a Python exception is raised and ``NULL`` is returned.  *sender*
    is the wrapped ``QObject`` derived instance that emits the signal.
    *signal* is the typed name of the signal.  *receiver* is the wrapped
    ``QObject`` derived instance or Python callable that the signal is
    connected to.  *slot* is the typed name of the slot, or ``NULL`` if
    *receiver* is a Python callable.  It is normally only used by PyQt to
    implement ``QObject.connect()``.

    This is only available if Qt support is enabled.


sipConvertFromSequenceIndex()
-----------------------------

int sipConvertFromSequenceIndex(int idx, int len)
    This converts a Python sequence index (i.e. where a negative value refers
    to the offset from the end of the sequence) to a C/C++ array index.  If the
    index was out of range then a negative value is returned and a Python
    exception raised.


sipConvertFromSliceObject()
---------------------------

int sipConvertFromSliceObject(PyObject \*slice, int length, int \*start, int \*stop, int \*step, int \*slicelength)
    This is a thin wrapper around the Python ``PySlice_GetIndicesEx()``
    function provided to make it easier to write handwritten code that is
    compatible with `SIP v3.x`_ and versions of Python earlier that v2.3.


sipConvertToCpp()
-----------------

void \*sipConvertToCpp(PyObject \*obj, sipWrapperType \*type, int \*iserr)
    This extracts the pointer to the C structure or C++ class instance from a
    wrapped instance object.  *obj* is the wrapped instance object (if it is
    ``Py_None`` then ``NULL`` is returned).  *type* is generated type
    corresponding to the C/C++ type returned.  It may be any class in the
    object's class hierarchy.  If there is an error then the location *iserr*
    points to is set to a non-zero value.


sipDisconnectRx()
-----------------

PyObject \*sipDisconnectRx(PyObject \*sender, const char \*signal, PyObject \*receiver, const char \*slot)
    This disconnects a signal from a signal or slot and returns ``Py_True`` if
    the signal was disconnected or ``Py_False`` if not.  If there was some
    other error then a Python exception is raised and ``NULL`` is returned.
    *sender* is the wrapped ``QObject`` derived instance that emits the signal.
    *signal* is the typed name of the signal.  *receiver* is the wrapped
    ``QObject`` derived instance or Python callable that the signal is
    connected to.  *slot* is the typed name of the slot, or ``NULL`` if
    *receiver* is a Python callable.  It is normally only used by PyQt to
    implement ``QObject.disconnect()``.

    This is only available if Qt support is enabled.


sipEmitSignal()
---------------

int sipEmitSignal(PyObject \*txobj, const char \*signal, PyObject \*args)
    This emits a signal and returns zero if there was no error.  If there was
    an error then a Python exception is raised and a negative value is
    returned.  *txobj* is the wrapped ``QObject`` derived instance that emits
    the signal.  *signal* is the typed name of the signal.  *args* is a Python
    tuple of the signal arguments.  It is normally only used by PyQt to
    implement ``QObject.emit()``.

    This is only available if Qt support is enabled.


sipFree()
---------

void sipFree(void \*mem)
    This returns an area of memory allocated by `sipMalloc()`_ to the heap.
    *mem* is a pointer to the area of memory.


sipGetSender()
--------------

void \*sipGetSender()
    This returns a pointer to the last ``QObject`` instance that emitted a Qt
    signal.  It is normally only used by PyQt to implement
    ``QObject.sender()``.

    This is only available if Qt support is enabled.


sipGetWrapper()
---------------

PyObject \*sipGetWrapper(void \*cppptr, sipWrapperType \*type)
    This returns a borrowed reference to the wrapped instance object for a C
    structure or C++ class instance.  If the structure or class instance
    hasn't been wrapped then ``NULL`` is returned (and no Python exception is
    raised).  *cppptr* is the pointer to the structure or class instance.
    *type* is the generated type corresponding to the C/C++ type.


sipIntTypeClassMap
------------------

This C structure is used with `sipMapIntToClass()`_ to define a mapping
between integer based RTTI and `generated type objects`_.  The structure
elements are as follows.

int typeInt
    The integer RTTI.

sipWrapperType \*\*pyType.
    A pointer to the corresponding Python type object.


sipIsSubClassInstance()
-----------------------

int sipIsSubClassInstance(PyObject \*obj, sipWrapperType \*type)
    This is a thin wrapper around the Python ``PyObject_TypeCheck()``
    function provided to make it easier to write handwritten code that is
    compatible with `SIP v3.x`_ and versions of Python earlier that v2.2.


sipMalloc()
-----------

void \*sipMalloc(size_t nbytes)
    This allocates an area of memory of size *nytes* on the heap using the
    Python ``PyMem_Malloc()`` function.  If there was an error then ``NULL`` is
    returned and a Python exception raised.  See `sipFree()`_.


sipMapIntToClass()
------------------

sipWrapperType \*sipMapIntToClass(int type, const sipIntTypeClassMap \*map, int maplen)
    This is used in `%ConvertToSubClassCode`_ code as a convenient way of
    converting integer based RTTI to the corresponding Python type object.
    *type* is the RTTI.  *map* is the table of known RTTI and the corresponding
    type objects (see sipIntTypeClassMap_).  The entries in the table must be
    sorted in ascending order of RTTI.  *maplen* is the number of entries in
    the table.  The corresponding Python type object is returned, or ``NULL``
    if *type* wasn't in *map*.


sipMapStringToClass()
---------------------

sipWrapperType \*sipMapStringToClass(char \*type, const sipStringTypeClassMap \*map, int maplen)
    This is used in `%ConvertToSubClassCode`_ code as a convenient way of
    converting ``'\0'`` terminated string based RTTI to the corresponding
    Python type object.  *type* is the RTTI.  *map* is the table of known RTTI
    and the corresponding type objects (see sipStringTypeClassMap_).  The
    entries in the table must be sorted in ascending order of RTTI.  *maplen*
    is the number of entries in the table.  The corresponding Python type
    object is returned, or ``NULL`` if *type* wasn't in *map*.


sipParseResult()
----------------

int sipParseResult(int \*iserr, PyObject \*method, PyObject \*result, char \*format, ...)
    This converts a Python object (usually returned by a method) to C/C++ based
    on a format string and associated values in a similar way to the Python
    ``PyArg_ParseTuple()`` function.  If there was an error then a negative
    value is returned and a Python exception is raised.  If *iserr* is not
    ``NULL`` then the location it points to is set to a non-zero value.
    *method* is the Python bound method that returned the *result* object.
    *format* is the string of format characters.

    This is normally called by handwritten code specified with the
    `%VirtualCatcherCode`_ directive with *method* being the supplied
    ``sipMethod`` and ``result`` being the value returned by
    `sipCallMethod()`_.

    If *format* begins and ends with parentheses then *result* must be a Python
    tuple and the rest of *format* is applied to the tuple contents.

    In the following description the first letter is the format character, the
    entry in parentheses is the Python object type that the format character
    will convert, and the entry in brackets are the types of the C/C++ values
    to be passed. 

    ``a`` (string) [char \*\*, int \*]
        Convert a Python string to a C/C++ character array and its length.  If
        the Python object is ``Py_None`` then the array and length are ``NULL``
        and zero respectively.

    ``b`` (integer) [bool \*]
        Convert a Python integer to a C/C++ ``bool``.

    ``c`` (string) [char \*]
        Convert a Python string of length 1 to a C/C++ ``char``.

    ``d`` (float) [double \*]
        Convert a Python floating point number to a C/C++ ``double``.

    ``e`` (integer) [enum \*]
        Convert Python integer to a C/C++ ``enum``.

    ``f`` (float) [double \*]
        Convert a Python floating point number to a C/C++ ``float``.

    ``h`` (integer) [short \*]
        Convert a Python integer to a C/C++ ``short``.

    ``i`` (integer) [int \*]
        Convert a Python integer to a C/C++ ``int``.

    ``l`` (integer) [long \*]
        Convert a Python integer to a C/C++ ``long``.

    ``s`` (string) [char \*\*]
        Convert a Python string to a C/C++ ``'\0'`` terminated string.  If the
        Python object is ``Py_None`` then the string is ``NULL``.

    ``L`` (object) [*type* \*(\*)(PyObject \*obj, int \*iserr), void \*\*]
        Convert a Python object to a C structure or a C++ class instance using
        a convertor function.  See `Generated Type Convertors`_.

    ``M`` (object) [*type* \*(\*)(PyObject \*obj, int \*iserr), void \*\*]
        Convert a Python object to a C structure or a C++ class instance using
        a convertor function.  If the structure or class instance pointer is
        ``NULL`` then return an error.  See `Generated Type Convertors`_.

    ``N`` (object) [PyTypeObject \*, PyObject \*\*]
        A Python object is checked to see if it is a certain type and then
        returned without any conversions.  The reference count is incremented.
        The Python object may be ``Py_None``.

    ``O`` (object) [PyObject \*\*]
        A Python object is returned without any conversions.  The reference
        count is incremented.

    ``T`` (object) [PyTypeObject \*, PyObject \*\*]
        A Python object is checked to see if it is a certain type and then
        returned without any conversions.  The reference count is incremented.
        The Python object may not be ``Py_None``.

    ``V`` (sip.voidptr) [void \*]
        Convert a Python ``sip.voidptr`` object to a C/C++ ``void *``.

    ``Z`` (object) []
        Check that a Python object is ``Py_None``.  No value is returned.


sipStringTypeClassMap
---------------------

This C structure is used with `sipMapStringToClass()`_ to define a mapping
between ``'\0'`` terminated string based RTTI and `generated type objects`_.
The structure elements are as follows.

char \*typeString
    The ``'\0'`` terminated string RTTI.

sipWrapperType \*\*pyType.
    A pointer to the corresponding Python type object.


sipTransfer()
-------------

void sipTransfer(PyObject \*obj, int tocpp)
    This transfers ownership of a Python wrapped instance either to or from
    Python (see `Ownership of Objects`_).  *obj* is the wrapped instance.  If
    *tocpp* is non-zero then ownership is transfered from Python to C/C++. If
    *tocpp* is zero then ownership is transfered from C/C++ to Python.


sipWrapperType
--------------

This is a C structure that represents a SIP generated type object.  It is an
extension of the Python ``PyTypeObject`` structure (which is itself an
extension of the Python ``PyObject`` structure) and so may be safely cast to
``PyTypeObject`` (and ``PyObject``).


Generated Type Convertors
-------------------------

SIP generates functions for all types being wrapped (including mapped types
defined with the `%MappedType`_ directive) that convert a Python object to the
C structure or C++ class instance.  The name of this convertor is the name of
the structure or class prefixed by ``sipForceConvertTo_``.

void \*sipForceConvertTo_*class*(PyObject \*obj, int \*iserr)
    *obj* is the Python object to convert.  If *obj* is ``NULL`` or the
    location pointed to by *iserr* is non-zero then the conversion is not
    attempted and ``NULL`` is returned.  If there was an error then the
    location pointed to by *iserr* is set to a non-zero value, a Python
    exception is raised, and ``NULL`` is returned.

SIP also generates functions for mapped types that convert a C structure or
C++ class instance to a Python object.  The name of this convertor is the name
of the structure or class prefixed by ``sipConvertFrom_``.

PyObject \*sipConvertFrom_*class*(void \*cppptr)
    *cppptr* is a pointer to the C structure or C++ class instance to convert.
    If there was an error then ``NULL`` is returned and a Python exception
    raised.

The convertor functions of all imported types are available to handwritten
code.


Generated Type Objects
----------------------

SIP generates a type object for each C structure or C++ class being wrapped.
These are sipWrapperType_ structures and are used extensively by the SIP API.

These objects are named with the structure or class name prefixed by
``sipClass_``.  For example, the type object for class ``Klass`` is
``sipClass_Klass``.

The type objects of all imported classes are available to handwritten code.


Generated Derived Classes
-------------------------

For most C++ classes being wrapped SIP generates a derived class with the same
name prefixed by ``sip``.  For example, the derived class for class ``Klass``
is ``sipKlass``.

If a C++ class doesn't have any virtual or protected methods in it or any of
it's super-class hierarchy, or does not emit any Qt signals, then a derived
class is not generated.

Most of the time handwritten code should ignore the derived classes.  The only
exception is that handwritten constructor code specified using the
`%MethodCode`_ directive should call the derived class's constructor (which
has the same C++ signature) rather then the wrapped class's constructor.


Using the SIP Module in Applications
====================================

The main purpose of the SIP module is to provide functionality common to all
SIP generated bindings.  It is loaded automatically and most of the time you
will completely ignore it.  However, it does expose some functionality that can
be used by applications.

cast(obj, type)
    This does the Python equivalent of casting a C++ instance to one of its
    super-class types.  *obj* is the Python object and *type* is the type.
    The type of *obj* must be derived from *type*.  A new Python object is
    returned that wraps the same C++ instance as *obj*, but has the type
    *type*.  It is usually used to gain access to super-class methods that have
    been hidden by derived class methods of the same name.

settracemask(mask)
    If the bindings have been created with SIP's ``-r`` command line option
    then the generated code will produce debugging statements that trace the
    execution of the code.  (It is particularly useful when trying to
    understand the operation of a C++ library's virtual function calls.)

    Debugging statements are generated at the following points:

    - in a C++ virtual function (*mask* is ``0x0001``)
    - in a C++ constructor (*mask* is ``0x0002``)
    - in a C++ destructor (*mask* is ``0x0004``)
    - in a Python type's __init__ method (*mask* is ``0x0008``)
    - in a Python type's __del__ method (*mask* is ``0x0010``)
    - in a Python type's ordinary method (*mask* is ``0x0020``).

    By default the trace mask is zero and all debugging statements are
    disabled.

transfer(obj, direction)
    Ownership of the wrapped C/C++ structure or class instance *obj* (i.e. the
    responsibility for deallocating it) is transferred to the C/C++ library (if
    *direction* is non-zero) or to the Python extension module (if *direction*
    is zero).

unwrapinstance(obj)
    Return the address, as a number, of the wrapped C/C++ structure or class
    instance *obj*.

wrapinstance(addr, type)
    A C/C++ structure or class instance is wrapped and the Python object
    created is returned.  If the instance has already been wrapped then a new
    reference to the existing object is returned.  *addr* is the address of
    the instance represented as a number.  *type* is the type of the object
    (e.g. ``qt.QWidget``).


The SIP Build System
====================

The purpose of the build system is to make it easy for you to write
configuration scripts in Python for your own bindings.  The build system takes
care of the details of particular combinations of platform and compiler.  It
supports over 50 different platform/compiler combinations.

The build system is implemented as a pure Python module called ``sipconfig``
that contains a number of classes and functions.  Using this module you can
write bespoke configuration scripts (e.g. PyQt's ``configure.py``) or use it
with other Python based build systems (e.g.
`Distutils <http://www.python.org/sigs/distutils-sig/distutils.html>`_ and
`SCons <http://www.scons.org>`_).

An important feature of SIP is the ability to generate bindings that are built
on top of existing bindings.  For example, both
`PyKDE <http://www.riverbankcomputing.co.uk/pykde/>`_ and
`PyQwt <http://pyqwt.sourceforge.net/>`_ are built on top of PyQt but all three
packages are maintained by different developers.  To make this easier PyQt
includes its own configuration module, ``pyqtconfig``, that contains additional
classes intended to be used by the configuration scripts of bindings built on
top of PyQt.  The SIP build system includes facilities that do a lot of the
work of creating these additional configuration modules.


``sipconfig`` Functions
-----------------------

create_config_module(module, template, content)
    This creates a configuration module (e.g. ``pyqtconfig``) from a template
    file and a string.

    ``module`` is the name of the configuration module file to create.

    ``template`` is the name of the template file.

    ``content`` is a string which replaces every occurence of the pattern
    ``@SIP_CONFIGURATION@`` in the template file.  The content string is
    usually created from a Python dictionary using
    ``sipconfig.create_content()``.

create_content(dict, dictname="_pkg_config")
    This converts a Python dictionary to a string that can be parsed by the
    Python interpreter and converted back to an equivalent dictionary.  It is
    typically used to generate the content string for
    ``sipconfig.create_config_module()``.

    ``dict`` is the Python dictionary to convert.

    ``dictname`` is the optional name of the dictionary.

    Returns the dictionary as a string.

error(msg)
    This displays an error message on ``stderr`` and calls ``sys.exit()`` with
    a value of 1.

    ``msg`` is the text of the message and should not include any newline
    characters.

format(msg, leftmargin=0, rightmargin=78)
    This formats a message by inserting newline characters at appropriate
    places.

    ``msg`` is the text of the message and should not include any newline
    characters.

    ``leftmargin`` is the optional position of the left margin.

    ``rightmargin`` is the optional position of the right margin.

inform(msg)
    This displays an information message on ``stdout``.

    ``msg`` is the text of the message and should not include any newline
    characters.

read_version(filename, description, numdefine=None, strdefine=None)
    This extracts version information for a package from a file, usually a C or
    C++ header file.  The version information must each be specified as a
    ``#define`` of a numeric (hexadecimal or decimal) value and/or a string
    value.

    ``filename`` is the name of the file to read.

    ``description`` is a descriptive name of the package used in error
    messages.

    ``numdefine`` is the optional name of the ``#define`` of the version as a
    number.  If it is ``None`` then the numeric version is ignored.

    ``strdefine`` is the optional name of the ``#define`` of the version as a
    string.  If it is ``None`` then the string version is ignored.

    Returns a tuple of the numeric and string versions.  ``sipconfig.error()``
    is called if either were required but could not be found.

version_to_sip_tag(version, tags, description)
    This converts a version number to a SIP version tag.  SIP uses the
    ``%Timeline`` directive to define the chronology of the different versions
    of the C/C++ library being wrapped.  Typically it is not necessary to
    define a version tag for every version of the library, but only for those
    versions that affect the library's API as SIP sees it.

    ``version`` is the numeric version number of the C/C++ library being
    wrapped.  If it is negative then the latest version is assumed.  (This is
    typically useful if a snapshot is indicated by a negative version number.)

    ``tags`` is the dictionary of SIP version tags keyed by the corresponding
    C/C++ library version number.  The tag used is the one with the smallest
    key (i.e. earliest version) that is greater than ``version``.

    ``description`` is a descriptive name of the C/C++ library used in error
    messages.

    Returns the SIP version tag.  ``sipconfig.error()`` is called if the C/C++
    library version number did not correspond to a SIP version tag.

version_to_string(v)
    This converts a 3 part version number encoded as a hexadecimal value to a
    string.

    ``v`` is the version number.

    Returns a string.


``sipconfig`` Classes
---------------------

Configuration
    This class encapsulates configuration values that can be accessed as
    instance objects.  A sub-class may provide a dictionary of additional
    configuration values in its constructor the elements of which will have
    precedence over the super-class's values.

    The following configuration values are provided:

        default_bin_dir
            The name of the directory where executables should be installed by
            default.

        default_mod_dir
            The name of the directory where SIP generated modules should be
            installed by default.

        default_sip_dir
            The name of the base directory where the ``.sip`` files for SIP
            generated modules should be installed by default.  A sub-directory
            with the same name as the module should be created and its ``.sip``
            files should be installed in the sub-directory.  The ``.sip``
            files only need to be installed if you might want to build other
            bindings based on them.

        py_inc_dir
            The name of the directory containing the ``Python.h`` header file.

        py_lib_dir
            The name of the directory containing the Python interpreter
            library.

        py_version
            The Python version as a 3 part hexadecimal number (e.g. v2.3.3 is
            represented as ``0x020303``).

        qt_dir
            The name of the Qt base directory.  The value is not present if Qt
            support is disabled.

        qt_edition
            The name of the Qt edition (e.g. enterprise, professional, free).
            The value is not present if Qt support is disabled.

        qt_inc_dir
            The name of the Qt include directory.  The value is not present if
            Qt support is disabled.

        qt_lib
            The name of the Qt library with platform dependent prefixes,
            suffixes and version numbers removed (e.g. qt, qt-mt).  The value
            is not present if Qt support is disabled.

        qt_lib_dir
            The name of the Qt library directory.  The value is not present if
            Qt support is disabled.

        qt_threaded
            A non-zero value if the Qt library includes support for threads.
            The value is not present if Qt support is disabled.

        qt_version
            The Qt version as a 3 part hexadecimal number (e.g. v3.3.0 is
            represented as ``0x030300``).  It is ``0`` if Qt support is
            disabled.

        qt_winconfig
            A string describing the Qt configuration under Windows.  The value
            is not present if Qt support is disabled.

        sip_bin
            The full pathname of the SIP executable.

        sip_inc_dir
            The name of the directory containing the ``sip.h`` header file.

        sip_mod_dir
            The name of the directory containing the SIP module.

        sip_version
            The SIP version as a 3 part hexadecimal number (e.g. v4.0.0 is
            represented as ``0x040000``).

        sip_version_str
            The SIP version as a string.  For development snapshots it will
            start with ``snapshot-``.

    __init__(self, sub_cfg=None)
        Initialise the instance.

        ``sub_cfg`` is an optional list of sub-class configurations.  It should
        only be used by the ``__init__()`` method of a sub-class to append its
        own dictionary of configuration values before passing the list to its
        super-class.

Makefile
    This class encapsulates a Makefile.  It is intended to be sub-classed to
    generate Makefiles for particular purposes.  It handles all platform and
    compiler specific flags, but allows them to be adjusted to suit the
    requirements of a particular module or program.  These are defined using a
    number of macros which can be accessed as instance objects.

    The following instance objects are provided to help in fine tuning the
    generated Makefile:

        chkdir
            A string that will check for the existence of a directory.

        config
            A reference to the ``configuration`` argument that was passed to
            the constructor.

        console
            A reference to the ``console`` argument that was passed to the
            constructor.

        copy
            A string that will copy a file.

        extra_cflags
            A list of additional flags passed to the C compiler.

        extra_cxxflags
            A list of additional flags passed to the C++ compiler.

        extra_defines
            A list of additional macro names passed to the C/C++ preprocessor.

        extra_include_dirs
            A list of additional include directories passed to the C/C++
            preprocessor.

        extra_lflags
            A list of additional flags passed to the linker.

        extra_lib_dirs
            A list of additional library directories passed to the linker.

        extra_libs
            A list of additional libraries passed to the linker.  The names of
            the libraries must be in platform neutral form (i.e. without any
            platform specific prefixes, version numbers or extensions).

        generator
            A string that defines the platform specific style of Makefile.  The
            only supported values are ``UNIX`` and something else that is not
            ``UNIX``.

        mkdir
            A string that will create a directory.

        rm
            A string that will remove a file.

    __init__(self, configuration, console=0, qt=0, opengl=0, python=0, threaded=0, warnings=None, debug=0, dir=None, makefile="Makefile", installs=None)
        Initialise the instance.

        ``configuration`` is the current configuration and is an instance of
        the ``Configuration`` class or a sub-class.

        ``console`` is set if the target is a console (rather than GUI) target.
        This only affects Windows and is ignored on other platforms.

        ``qt`` is set if the target uses Qt.

        ``opengl`` is set if the target uses OpenGL.

        ``python`` is set if the target uses Python.h.

        ``threaded`` is set if the target requires thread support.  It is set
        automatically if the target uses Qt and Qt has thread support enabled.

        ``warnings`` is set if compiler warning messages should be enabled.
        The default of ``None`` means that warnings are enabled for SIP v4.x
        and disabled for SIP v3.x.

        ``debug`` is set if debugging symbols should be generated.

        ``dir`` is the name of the directory where build files are read from
        and Makefiles are written to.  The default of ``None`` means the
        current directory is used.

        ``makefile`` is the name of the generated Makefile.

        ``installs`` is a list of extra install targets.  Each element is a two
        part list, the first of which is the source and the second is the
        destination.  If the source is another list then it is a list of source
        files and the destination is a directory.

    clean_build_file_objects(self, mfile, build)
        This generates the Makefile commands that will remove any files
        generated during the build of the default target.

        ``mfile`` is the Python file object of the Makefile.

        ``build`` is the dictionary created from parsing the build file.

    finalise(self)
        This is called just before the Makefile is generated to ensure that it
        is fully configured.  It must be reimplemented by a sub-class.

    generate(self)
        This generates the Makefile.

    generate_macros_and_rules(self, mfile)
        This is the default implementation of the Makefile macros and rules
        generation.

        ``mfile`` is the Python file object of the Makefile.

    generate_target_clean(self, mfile)
        This is the default implementation of the Makefile clean target
        generation.

        ``mfile`` is the Python file object of the Makefile.

    generate_target_default(self, mfile)
        This is the default implementation of the Makefile default target
        generation.

        ``mfile`` is the Python file object of the Makefile.

    generate_target_install(self, mfile)
        This is the default implementation of the Makefile install target
        generation.

        ``mfile`` is the Python file object of the Makefile.

    install_file(self, mfile, src, dst)
        This generates the Makefile commands to install one or more files to a
        directory.

        ``mfile`` is the Python file object of the Makefile.

        ``src`` is the name of a single file to install or a list of a number
        of files to install.

        ``dst`` is the name of the destination directory.

    optional_list(self, name)
        This returns an optional Makefile macro as a list.

        ``name`` is the name of the macro.

        Returns the macro as a list.

    optional_string(self, name, default="")
        This returns an optional Makefile macro as a string.

        ``name`` is the name of the macro.

        ``default`` is the optional default value of the macro.

        Returns the macro as a string.

    parse_build_file(self, filename)
        This parses a build file (created with the ``-b`` SIP command line
        option).

        ``filename`` is the name of the build file.

        Returns a dictionary corresponding to the parsed build file.

    platform_lib(self, clib)
        This converts a library name to a platform specific form.

        ``clib`` is the name of the library in cannonical form.

        Return the platform specific name.

    ready(self)
        This is called to ensure that the Makefile is fully configured.  It is
        normally called automatically when needed.

    required_string(self, name)
        This returns a required Makefile macro as a string.

        ``name`` is the name of the macro.

        Returns the macro as a string.  An exception is raised if the macro
        does not exist or has an empty value.

ModuleMakefile(Makefile)
    This class encapsulates a Makefile to build a generic Python extension
    module.

    __init__(self, configuration, build_file, install_dir=None, static=0, console=0, opengl=0, threaded=0, warnings=None, debug=0, dir=None, makefile="Makefile", installs=None)
        Initialise the instance.

        ``configuration`` - see ``sipconfig.Makefile.__init__()``.

        ``build_file`` is the name of the build file.  Build files are
        generated using the ``-b`` SIP command line option.

        ``install_dir`` is the name of the directory where the module will be
        optionally installed.

        ``static`` is set if the module should be built as a static library.

        ``console`` - see ``sipconfig.Makefile.__init__()``.

        ``qt`` - see ``sipconfig.Makefile.__init__()``.

        ``opengl`` - see ``sipconfig.Makefile.__init__()``.

        ``threaded`` - see ``sipconfig.Makefile.__init__()``.

        ``warnings`` - see ``sipconfig.Makefile.__init__()``.

        ``debug`` - see ``sipconfig.Makefile.__init__()``.

        ``dir`` - see ``sipconfig.Makefile.__init__()``.

        ``makefile`` - see ``sipconfig.Makefile.__init__()``.

        ``installs`` - see ``sipconfig.Makefile.__init__()``.

    finalise(self)
        This is a reimplementation of ``sipconfig.Makefile.finalise()``.

    generate_macros_and_rules(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_macros_and_rules()``.

    generate_target_clean(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_target_clean()``.

    generate_target_default(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_target_default()``.

    generate_target_install(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_target_install()``.

    module_as_lib(self, mname)
        This returns the name of a SIP v3.x module for when it is used as a
        library to be linked against.  An exception will be raised if it is
        used with SIP v4.x modules.

        ``mname`` is the name of the module.

        Returns the corresponding library name.

ParentMakefile(Makefile)
    This class encapsulates a Makefile that sits above a number of other
    Makefiles in sub-directories.

    __init__(self, configuration, subdirs, dir=None, makefile="Makefile", installs=None)
        Initialise the instance.

        ``configuration`` - see ``sipconfig.Makefile.__init__()``.

        ``subdirs`` is the sequence of sub-directories.

        ``dir`` - see ``sipconfig.Makefile.__init__()``.

        ``makefile`` - see ``sipconfig.Makefile.__init__()``.

        ``installs`` - see ``sipconfig.Makefile.__init__()``.

    generate_macros_and_rules(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_macros_and_rules()``.

    generate_target_clean(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_target_clean()``.

    generate_target_default(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_target_default()``.

    generate_target_install(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_target_install()``.

ProgramMakefile(Makefile)
    This class encapsulates a Makefile to build an executable program.

    __init__(self, configuration, build_file=None, install_dir=None, console=0, qt=0, opengl=0, python=0, threaded=0, warnings=None, debug=0, dir=None, makefile="Makefile", installs=None)
        Initialise the instance.

        ``configuration`` - see ``sipconfig.Makefile.__init__()``.

        ``build_file`` is the name of the optional build file.  Build files are
        generated using the ``-b`` SIP command line option.

        ``install_dir`` is the name of the directory where the executable
        program will be optionally installed.

        ``console`` - see ``sipconfig.Makefile.__init__()``.

        ``qt`` - see ``sipconfig.Makefile.__init__()``.

        ``opengl`` - see ``sipconfig.Makefile.__init__()``.

        ``python`` - see ``sipconfig.Makefile.__init__()``.

        ``threaded`` - see ``sipconfig.Makefile.__init__()``.

        ``warnings`` - see ``sipconfig.Makefile.__init__()``.

        ``debug`` - see ``sipconfig.Makefile.__init__()``.

        ``dir`` - see ``sipconfig.Makefile.__init__()``.

        ``makefile`` - see ``sipconfig.Makefile.__init__()``.

        ``installs`` - see ``sipconfig.Makefile.__init__()``.

    build_command(self, source)
        This creates a single command line that will create an executable
        program from a single source file.

        ``source`` is the name of the source file.

        Returns a tuple of the name of the executable that will be created and
        the command line.

    finalise(self)
        This is a reimplementation of ``sipconfig.Makefile.finalise()``.

    generate_macros_and_rules(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_macros_and_rules()``.

    generate_target_clean(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_target_clean()``.

    generate_target_default(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_target_default()``.

    generate_target_install(self, mfile)
        This is a reimplementation of
        ``sipconfig.Makefile.generate_target_install()``.

SIPModuleMakefile(ModuleMakefile)
    This class encapsulates a Makefile to build a SIP generated Python
    extension module.

    finalise(self)
        This is a reimplementation of ``sipconfig.Makefile.finalise()``.
