.. highlightlang:: c .. _moduleobjects: Module Objects -------------- .. index:: object: module There are only a few functions special to module objects. .. cvar:: PyTypeObject PyModule_Type .. index:: single: ModuleType (in module types) This instance of :ctype:`PyTypeObject` represents the Python module type. This is exposed to Python programs as ``types.ModuleType``. .. cfunction:: int PyModule_Check(PyObject *p) Return true if *p* is a module object, or a subtype of a module object. .. cfunction:: int PyModule_CheckExact(PyObject *p) Return true if *p* is a module object, but not a subtype of :cdata:`PyModule_Type`. .. cfunction:: PyObject* PyModule_New(const char *name) .. index:: single: __name__ (module attribute) single: __doc__ (module attribute) single: __file__ (module attribute) Return a new module object with the :attr:`__name__` attribute set to *name*. Only the module's :attr:`__doc__` and :attr:`__name__` attributes are filled in; the caller is responsible for providing a :attr:`__file__` attribute. .. cfunction:: PyObject* PyModule_GetDict(PyObject *module) .. index:: single: __dict__ (module attribute) Return the dictionary object that implements *module*'s namespace; this object is the same as the :attr:`__dict__` attribute of the module object. This function never fails. It is recommended extensions use other :cfunc:`PyModule_\*` and :cfunc:`PyObject_\*` functions rather than directly manipulate a module's :attr:`__dict__`. .. cfunction:: char* PyModule_GetName(PyObject *module) .. index:: single: __name__ (module attribute) single: SystemError (built-in exception) Return *module*'s :attr:`__name__` value. If the module does not provide one, or if it is not a string, :exc:`SystemError` is raised and *NULL* is returned. .. cfunction:: char* PyModule_GetFilename(PyObject *module) .. index:: single: __file__ (module attribute) single: SystemError (built-in exception) Return the name of the file from which *module* was loaded using *module*'s :attr:`__file__` attribute. If this is not defined, or if it is not a string, raise :exc:`SystemError` and return *NULL*. .. cfunction:: void* PyModule_GetState(PyObject *module) Return the "state" of the module, that is, a pointer to the block of memory allocated at module creation time, or *NULL*. See :cmember:`PyModuleDef.m_size`. .. cfunction:: PyModuleDef* PyModule_GetDef(PyObject *module) Return a pointer to the :ctype:`PyModuleDef` struct from which the module was created, or *NULL* if the module wasn't created with :cfunc:`PyModule_Create`. Initializing C modules ^^^^^^^^^^^^^^^^^^^^^^ These functions are usually used in the module initialization function. .. cfunction:: PyObject* PyModule_Create(PyModuleDef *module) Create a new module object, given the definition in *module*. This behaves like :cfunc:`PyModule_Create2` with *module_api_version* set to :const:`PYTHON_API_VERSION`. .. cfunction:: PyObject* PyModule_Create2(PyModuleDef *module, int module_api_version) Create a new module object, given the definition in *module*, assuming the API version *module_api_version*. If that version does not match the version of the running interpreter, a :exc:`RuntimeWarning` is emitted. .. note:: Most uses of this function should be using :cfunc:`PyModule_Create` instead; only use this if you are sure you need it. .. ctype:: PyModuleDef This struct holds all information that is needed to create a module object. There is usually only one static variable of that type for each module, which is statically initialized and then passed to :cfunc:`PyModule_Create` in the module initialization function. .. cmember:: PyModuleDef_Base m_base Always initialize this member to :const:`PyModuleDef_HEAD_INIT`. .. cmember:: char* m_name Name for the new module. .. cmember:: char* m_doc Docstring for the module; usually a docstring variable created with :cfunc:`PyDoc_STRVAR` is used. .. cmember:: Py_ssize_t m_size If the module object needs additional memory, this should be set to the number of bytes to allocate; a pointer to the block of memory can be retrieved with :cfunc:`PyModule_GetState`. If no memory is needed, set this to ``-1``. This memory should be used, rather than static globals, to hold per-module state, since it is then safe for use in multiple sub-interpreters. It is freed when the module object is deallocated, after the :cmember:`m_free` function has been called, if present. .. cmember:: PyMethodDef* m_methods A pointer to a table of module-level functions, described by :ctype:`PyMethodDef` values. Can be *NULL* if no functions are present. .. cmember:: inquiry m_reload Currently unused, should be *NULL*. .. cmember:: traverseproc m_traverse A traversal function to call during GC traversal of the module object, or *NULL* if not needed. .. cmember:: inquiry m_clear A clear function to call during GC clearing of the module object, or *NULL* if not needed. .. cmember:: freefunc m_free A function to call during deallocation of the module object, or *NULL* if not needed. .. cfunction:: int PyModule_AddObject(PyObject *module, const char *name, PyObject *value) Add an object to *module* as *name*. This is a convenience function which can be used from the module's initialization function. This steals a reference to *value*. Return ``-1`` on error, ``0`` on success. .. cfunction:: int PyModule_AddIntConstant(PyObject *module, const char *name, long value) Add an integer constant to *module* as *name*. This convenience function can be used from the module's initialization function. Return ``-1`` on error, ``0`` on success. .. cfunction:: int PyModule_AddStringConstant(PyObject *module, const char *name, const char *value) Add a string constant to *module* as *name*. This convenience function can be used from the module's initialization function. The string *value* must be null-terminated. Return ``-1`` on error, ``0`` on success. .. cfunction:: int PyModule_AddIntMacro(PyObject *module, macro) Add an int constant to *module*. The name and the value are taken from *macro*. For example ``PyModule_AddConstant(module, AF_INET)`` adds the int constant *AF_INET* with the value of *AF_INET* to *module*. Return ``-1`` on error, ``0`` on success. .. cfunction:: int PyModule_AddStringMacro(PyObject *module, macro) Add a string constant to *module*.