meson/docs/markdown/Python-module.md

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short-description: Generic python module authors: - name: Mathieu Duponchelle email: mathieu@centricular.com years: [2018] has-copyright: false ...

Python module

This module provides support for finding and building extensions against python installations, be they python 2 or 3.

Added 0.46.0

Functions

find_installation()

pymod.find_installation(name_or_path, ...)

Find a python installation matching name_or_path.

That argument is optional, if not provided then the returned python installation will be the one used to run Meson.

If provided, it can be:

• A simple name, eg python-2.7, Meson will look for an external program named that way, using find_program

• A path, eg /usr/local/bin/python3.4m

• One of python2 or python3: in either case, the module will try some alternative names: py -2 or py -3 on Windows, and python everywhere. In the latter case, it will check whether the version provided by the sysconfig module matches the required major version

Keyword arguments are the following:

• required: by default, required is set to true and Meson will abort if no python installation can be found. If required is set to false, Meson will continue even if no python installation was found. You can then use the .found() method on the returned object to check whether it was found or not. Since 0.48.0 the value of a feature option can also be passed to the required keyword argument.
• disabler: if true and no python installation can be found, return a @disabler object instead of a not-found object. Since 0.49.0
• modules: a list of module names that this python installation must have. Since 0.51.0

Returns: a [python installation][python_installation object]

python_installation object

The python_installation object is an @external_program, with several added methods.

Methods

path()

str py_installation.path()

Added 0.50.0

Works like the path method of other ExternalProgram objects. Was not provided prior to 0.50.0 due to a bug.

extension_module()

shared_module py_installation.extension_module(module_name, list_of_sources, ...)

Create a shared_module target that is named according to the naming conventions of the target platform.

All positional and keyword arguments are the same as for shared_module, excluding name_suffix and name_prefix, and with the addition of the following:

• subdir: By default, Meson will install the extension module in the relevant top-level location for the python installation, eg /usr/lib/site-packages. When subdir is passed to this method, it will be appended to that location. This keyword argument is mutually exclusive with install_dir

Additionally, the following diverge from shared_module's default behavior:

• gnu_symbol_visibility: if unset, it will default to 'hidden' on versions of Python that support this (the python headers define PyMODINIT_FUNC has default visibility).

extension_module does not add any dependencies to the library so user may need to add dependencies : py_installation.dependency(), see dependency.

Returns: a @build_tgt object

dependency()

python_dependency py_installation.dependency(...)

This method accepts no positional arguments, and the same keyword arguments as the standard dependency function. It also supports the following keyword argument:

• embed: (since 0.53.0) If true, Meson will try to find a python dependency that can be used for embedding python into an application.
• disabler (since 0.60.0): if true and the dependency couldn't be found, returns a disabler object instead of a not-found dependency.

Returns: a [python dependency][python_dependency object]

install_sources()

void py_installation.install_sources(list_of_files, ...)

Install actual python sources (.py).

All positional and keyword arguments are the same as for install_data, with the addition of the following:

Since 0.60.0 python.platlibdir and python.purelibdir options can be used to control the default installation path. See Python module options.

• pure: On some platforms, architecture independent files are expected to be placed in a separate directory. However, if the python sources should be installed alongside an extension module built with this module, this keyword argument can be used to override that behaviour. Defaults to true

• subdir: See documentation for the argument of the same name to [][extension_module()]

• install_tag (since 0.60.0): A string used by meson install --tags command to install only a subset of the files. By default it has the tag python-runtime.

get_install_dir()

string py_installation.get_install_dir(...)

Retrieve the directory [][install_sources()] will install to.

It can be useful in cases where install_sources cannot be used directly, for example when using configure_file.

This function accepts no arguments, its keyword arguments are the same as [][install_sources()].

Since 0.60.0 python.platlibdir and python.purelibdir options can be used to control the default installation path. See Python module options.

Returns: A string

language_version()

string py_installation.language_version()

Get the major.minor python version, eg 2.7.

The version is obtained through the sysconfig module.

This function expects no arguments or keyword arguments.

Returns: A string

get_path()

string py_installation.get_path(path_name, fallback)

Get a path as defined by the sysconfig module.

For example:

purelib = py_installation.get_path('purelib')

This function requires at least one argument, path_name, which is expected to be a non-empty string.

If fallback is specified, it will be returned if no path with the given name exists. Otherwise, attempting to read a non-existing path will cause a fatal error.

Returns: A string

has_path()

    bool py_installation.has_path(path_name)

Returns: true if a path named path_name can be retrieved with [][get_path()], false otherwise.

get_variable()

string py_installation.get_variable(variable_name, fallback)

Get a variable as defined by the sysconfig module.

For example:

py_bindir = py_installation.get_variable('BINDIR', '')

This function requires at least one argument, variable_name, which is expected to be a non-empty string.

If fallback is specified, it will be returned if no variable with the given name exists. Otherwise, attempting to read a non-existing variable will cause a fatal error.

Returns: A string

has_variable()

    bool py_installation.has_variable(variable_name)

Returns: true if a variable named variable_name can be retrieved with [][get_variable()], false otherwise.

python_dependency object

This @dep object subclass will try various methods to obtain the compiler and linker arguments, starting with pkg-config then potentially using information obtained from python's sysconfig module.

It exposes the same methods as its parent class.