PyModule_Type
Part of the
.This instance of
represents the Python module type. This is exposed to Python programs as
.
intPyModule_Check(
*p)
Return true if p is a module object, or a subtype of a module object. This function always succeeds.
intPyModule_CheckExact(
*p)
Return true if p is a module object, but not a subtype of
. This function always succeeds.
*PyModule_NewObject(
*name)
Return value: New reference. Part of the
since version 3.7.Return a new module object with
set to name. The module’s __name__,
,
and
attributes are filled in (all but __name__ are set to None). The caller is responsible for setting a
attribute.
Return NULL with an exception set on error.
Added in version 3.3.
*PyModule_New(constchar*name)
Return value: New reference. Part of the
.Similar to
, but the name is a UTF-8 encoded string instead of a Unicode object.
*PyModule_GetDict(
*module)
Return value: Borrowed reference. Part of the
.Return the dictionary object that implements module’s namespace; this object is the same as the
attribute of the module object. If module is not a module object (or a subtype of a module object),
is raised and NULL is returned.
It is recommended extensions use other PyModule_* and PyObject_* functions rather than directly manipulate a module’s
.
The returned reference is borrowed from the module; it is valid until the module is destroyed.
*PyModule_GetNameObject(
*module)
Return value: New reference. Part of the
since version 3.7.Return module’s
value. If the module does not provide one, or if it is not a string,
is raised and NULL is returned.
Added in version 3.3.
constchar*PyModule_GetName(
*module)
Part of the
.Similar to
but return the name encoded to 'utf-8'.
The returned buffer is only valid until the module is renamed or destroyed. Note that Python code may rename a module by setting its
attribute.
void*PyModule_GetState(
*module)
Part of the
.Return the “state” of the module, that is, a pointer to the block of memory allocated at module creation time, or NULL. See
.
*PyModule_GetDef(
*module)
Part of the
.Return a pointer to the
struct from which the module was created, or NULL if the module wasn’t created from a definition.
On error, return NULL with an exception set. Use
to tell this case apart from a missing PyModuleDef.
*PyModule_GetFilenameObject(
*module)
Return value: New reference. Part of the
.Return the name of the file from which module was loaded using module’s
attribute. If this is not defined, or if it is not a string, raise
and return NULL; otherwise return a reference to a Unicode object.
Added in version 3.2.
constchar*PyModule_GetFilename(
*module)
Part of the
.Similar to
but return the filename encoded to ‘utf-8’.
The returned buffer is only valid until the module’s
attribute is reassigned or the module is destroyed.
Deprecated since version 3.2:
raises
on unencodable filenames, use
instead.
Module definitions
The functions in the previous section work on any module object, including modules imported from Python code.
Modules defined using the C API typically use a module definition,
– a statically allocated, constant “description” of how a module should be created.
The definition is usually used to define an extension’s “main” module object (see
for details). It is also used to
create extension modules dynamically
.
Unlike
, the definition allows management of module state – a piece of memory that is allocated and cleared together with the module object. Unlike the module’s Python attributes, Python code cannot replace or delete data stored in module state.
typePyModuleDef
Part of the
(including all members).The module definition struct, which holds all information needed to create a module object. This structure must be statically allocated (or be otherwise guaranteed to be valid while any modules created from it exist). Usually, there is only one variable of this type for each extension module.
PyModuleDef_Basem_base
Always initialize this member to PyModuleDef_HEAD_INIT.
constchar*m_name
Name for the new module.
constchar*m_doc
Docstring for the module; usually a docstring variable created with
is used.
m_size
Module state may be kept in a per-module memory area that can be retrieved with
, rather than in static globals. This makes modules safe for use in multiple sub-interpreters.
This memory area is allocated based on m_size on module creation, and freed when the module object is deallocated, after the
function has been called, if present.
Setting it to a non-negative value means that the module can be re-initialized and specifies the additional amount of memory it requires for its state.
Setting m_size to -1 means that the module does not support sub-interpreters, because it has global state. Negative m_size is only allowed when using
legacy single-phase initialization
or when
.
See
for more details.
*m_methods
A pointer to a table of module-level functions, described by
values. Can be NULL if no functions are present.
*m_slots
An array of slot definitions for multi-phase initialization, terminated by a {0,NULL} entry. When using legacy single-phase initialization, m_slots must be NULL.
Changed in version 3.5: Prior to version 3.5, this member was always set to NULL, and was defined as:
m_traverse
A traversal function to call during GC traversal of the module object, or NULL if not needed.
This function is not called if the module state was requested but is not allocated yet. This is the case immediately after the module is created and before the module is executed (
function). More precisely, this function is not called if
is greater than 0 and the module state (as returned by
) is NULL.
Changed in version 3.9: No longer called before the module state is allocated.
m_clear
A clear function to call during GC clearing of the module object, or NULL if not needed.
This function is not called if the module state was requested but is not allocated yet. This is the case immediately after the module is created and before the module is executed (
function). More precisely, this function is not called if
is greater than 0 and the module state (as returned by
) is NULL.
Like
, this function is not always called before a module is deallocated. For example, when reference counting is enough to determine that an object is no longer used, the cyclic garbage collector is not involved and
is called directly.
Changed in version 3.9: No longer called before the module state is allocated.
m_free
A function to call during deallocation of the module object, or NULL if not needed.
This function is not called if the module state was requested but is not allocated yet. This is the case immediately after the module is created and before the module is executed (
function). More precisely, this function is not called if
is greater than 0 and the module state (as returned by
) is NULL.
Changed in version 3.9: No longer called before the module state is allocated.
PyModuleDef_Type
Part of the
since version 3.5.The type of PyModuleDef objects.
Module slots
typePyModuleDef_Slot
Part of the
(including all members) since version 3.5.intslot
A slot ID, chosen from the available values explained below.
void*value
Value of the slot, whose meaning depends on the slot ID.
Added in version 3.5.
The available slot types are:
Py_mod_create
Part of the
since version 3.5.Specifies a function that is called to create the module object itself. The value pointer of this slot must point to a function of the signature:
*create_module(
*spec,
*def)
The function receives a
instance, as defined in
, and the module definition. It should return a new module object, or set an error and return NULL.
This function should be kept minimal. In particular, it should not call arbitrary Python code, as trying to import the same module again may result in an infinite loop.
Multiple Py_mod_create slots may not be specified in one module definition.
If Py_mod_create is not specified, the import machinery will create a normal module object using
. The name is taken from spec, not the definition, to allow extension modules to dynamically adjust to their place in the module hierarchy and be imported under different names through symlinks, all while sharing a single module definition.
There is no requirement for the returned object to be an instance of
. Any type can be used, as long as it supports setting and getting import-related attributes. However, only PyModule_Type instances may be returned if the PyModuleDef has non-NULLm_traverse, m_clear, m_free; non-zero m_size; or slots other than Py_mod_create.
Added in version 3.5.
Py_mod_exec
Part of the
since version 3.5.Specifies a function that is called to execute the module. This is equivalent to executing the code of a Python module: typically, this function adds classes and constants to the module. The signature of the function is:
intexec_module(
*module)
If multiple Py_mod_exec slots are specified, they are processed in the order they appear in the m_slots array.
Added in version 3.5.
Py_mod_multiple_interpreters
Part of the
since version 3.12.Specifies one of the following values:
Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED
The module does not support being imported in subinterpreters.
Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED
The module supports being imported in subinterpreters, but only when they share the main interpreter’s GIL. (See
.)
Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
The module supports being imported in subinterpreters, even when they have their own GIL. (See
.)
This slot determines whether or not importing this module in a subinterpreter will fail.
Multiple Py_mod_multiple_interpreters slots may not be specified in one module definition.
If Py_mod_multiple_interpreters is not specified, the import machinery defaults to Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED.
Added in version 3.12.
Py_mod_gil
Part of the
since version 3.13.Specifies one of the following values:
Py_MOD_GIL_USED
The module depends on the presence of the global interpreter lock (GIL), and may access global state without synchronization.
Py_MOD_GIL_NOT_USED
The module is safe to run without an active GIL.
This slot is ignored by Python builds not configured with
. Otherwise, it determines whether or not importing this module will cause the GIL to be automatically enabled. See
for more detail.
Multiple Py_mod_gil slots may not be specified in one module definition.
If Py_mod_gil is not specified, the import machinery defaults to Py_MOD_GIL_USED.
Added in version 3.13.
Creating extension modules dynamically
The following functions may be used to create a module outside of an extension’s
. They are also used in
.
*PyModule_Create(
*def)
Return value: New reference.Create a new module object, given the definition in def. This is a macro that calls
with module_api_version set to
, or to
if using the
.
*PyModule_Create2(
*def, intmodule_api_version)
Return value: New reference. Part of the
.Create a new module object, given the definition in def, assuming the API version module_api_version. If that version does not match the version of the running interpreter, a
is emitted.
Return NULL with an exception set on error.
This function does not support slots. The
member of def must be NULL.
Note
Most uses of this function should be using
instead; only use this if you are sure you need it.
*PyModule_FromDefAndSpec(
*def,
*spec)
Return value: New reference.This macro calls
with module_api_version set to
, or to
if using the
.
Added in version 3.5.
*PyModule_FromDefAndSpec2(
*def,
*spec, intmodule_api_version)
Return value: New reference. Part of the
since version 3.7.Create a new module object, given the definition in def and the ModuleSpec spec, assuming the API version module_api_version. If that version does not match the version of the running interpreter, a
is emitted.
Return NULL with an exception set on error.
Note that this does not process execution slots (
). Both PyModule_FromDefAndSpec and PyModule_ExecDef must be called to fully initialize a module.
Note
Most uses of this function should be using
instead; only use this if you are sure you need it.
Added in version 3.5.
intPyModule_ExecDef(
*module,
*def)
Part of the
since version 3.7.Process any execution slots (
) given in def.
Added in version 3.5.
PYTHON_API_VERSION
The C API version. Defined for backwards compatibility.
Currently, this constant is not updated in new Python versions, and is not useful for versioning. This may change in the future.
PYTHON_ABI_VERSION
Defined as 3 for backwards compatibility.
Currently, this constant is not updated in new Python versions, and is not useful for versioning. This may change in the future.
Support functions
The following functions are provided to help initialize a module state. They are intended for a module’s execution slots (
), the initialization function for legacy
, or code that creates modules dynamically.
intPyModule_AddObjectRef(
*module, constchar*name,
*value)
Part of the
since version 3.10.Add an object to module as name. This is a convenience function which can be used from the module’s initialization function.
On success, return 0. On error, raise an exception and return -1.
Example usage:
staticintadd_spam(PyObject*module,intvalue){PyObject*obj=PyLong_FromLong(value);if(obj==NULL){return-1;}intres=PyModule_AddObjectRef(module,"spam",obj);Py_DECREF(obj);returnres;}To be convenient, the function accepts NULLvalue with an exception set. In this case, return -1 and just leave the raised exception unchanged.
The example can also be written without checking explicitly if obj is NULL:
staticintadd_spam(PyObject*module,intvalue){PyObject*obj=PyLong_FromLong(value);intres=PyModule_AddObjectRef(module,"spam",obj);Py_XDECREF(obj);returnres;}Note that Py_XDECREF() should be used instead of Py_DECREF() in this case, since obj can be NULL.
The number of different name strings passed to this function should be kept small, usually by only using statically allocated strings as name. For names that aren’t known at compile time, prefer calling
and
directly. For more details, see
, which may be used internally to create a key object.
Added in version 3.10.
intPyModule_Add(
*module, constchar*name,
*value)
Part of the
since version 3.13.Similar to
, but “
” a reference to value (even on error). It can be called with a result of function that returns a new reference without bothering to check its result or even saving it to a variable.
Example usage:
if(PyModule_Add(module,"spam",PyBytes_FromString(value))<0){gotoerror;}Added in version 3.13.
intPyModule_AddObject(
*module, constchar*name,
*value)
Part of the
.Similar to
, but
a reference to value on success (if it returns 0).
The new
or
functions are recommended, since it is easy to introduce reference leaks by misusing the
function.
Note
Unlike other functions that steal references, PyModule_AddObject() only releases the reference to valueon success.
This means that its return value must be checked, and calling code must
value manually on error.
Example usage:
PyObject*obj=PyBytes_FromString(value);if(PyModule_AddObject(module,"spam",obj)<0){// If 'obj' is not NULL and PyModule_AddObject() failed,// 'obj' strong reference must be deleted with Py_XDECREF().// If 'obj' is NULL, Py_XDECREF() does nothing.Py_XDECREF(obj);gotoerror;}// PyModule_AddObject() stole a reference to obj:// Py_XDECREF(obj) is not needed here.intPyModule_AddIntConstant(
*module, constchar*name, longvalue)
Part of the
.Add an integer constant to module as name. This convenience function can be used from the module’s initialization function. Return -1 with an exception set on error, 0 on success.
This is a convenience function that calls
and
; see their documentation for details.
intPyModule_AddStringConstant(
*module, constchar*name, constchar*value)
Part of the
.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 with an exception set on error, 0 on success.
This is a convenience function that calls
and
; see their documentation for details.
PyModule_AddIntMacro(module, macro)
Add an int constant to module. The name and the value are taken from macro. For example PyModule_AddIntMacro(module,AF_INET) adds the int constant AF_INET with the value of AF_INET to module. Return -1 with an exception set on error, 0 on success.
PyModule_AddStringMacro(module, macro)
Add a string constant to module.
intPyModule_AddType(
*module,
*type)
Part of the
since version 3.10.Add a type object to module. The type object is finalized by calling internally
. The name of the type object is taken from the last component of
after dot. Return -1 with an exception set on error, 0 on success.
Added in version 3.9.
intPyModule_AddFunctions(
*module,
*functions)
Part of the
since version 3.7.Add the functions from the NULL terminated functions array to module. Refer to the
documentation for details on individual entries (due to the lack of a shared module namespace, module level “functions” implemented in C typically receive the module as their first parameter, making them similar to instance methods on Python classes).
This function is called automatically when creating a module from PyModuleDef (such as when using
, PyModule_Create, or PyModule_FromDefAndSpec). Some module authors may prefer defining functions in multiple
arrays; in that case they should call this function directly.
The functions array must be statically allocated (or otherwise guaranteed to outlive the module object).
Added in version 3.5.
intPyModule_SetDocString(
*module, constchar*docstring)
Part of the
since version 3.7.Set the docstring for module to docstring. This function is called automatically when creating a module from PyModuleDef (such as when using
, PyModule_Create, or PyModule_FromDefAndSpec).
Return 0 on success. Return -1 with an exception set on error.
Added in version 3.5.
intPyUnstable_Module_SetGIL(
*module, void*gil)
This is
. It may change without warning in minor releases.
Indicate that module does or does not support running without the global interpreter lock (GIL), using one of the values from
. It must be called during module’s initialization function when using
Legacy single-phase initialization
. If this function is not called during module initialization, the import machinery assumes the module does not support running without the GIL. This function is only available in Python builds configured with
. Return -1 with an exception set on error, 0 on success.
Added in version 3.13.
Module lookup (single-phase initialization)
The legacy
initialization scheme creates singleton modules that can be looked up in the context of the current interpreter. This allows the module object to be retrieved later with only a reference to the module definition.
These functions will not work on modules created using multi-phase initialization, since multiple such modules can be created from a single definition.
*PyState_FindModule(
*def)
Return value: Borrowed reference. Part of the
.Returns the module object that was created from def for the current interpreter. This method requires that the module object has been attached to the interpreter state with
beforehand. In case the corresponding module object is not found or has not been attached to the interpreter state yet, it returns NULL.
intPyState_AddModule(
*module,
*def)
Part of the
since version 3.3.Attaches the module object passed to the function to the interpreter state. This allows the module object to be accessible via
.
Only effective on modules created using single-phase initialization.
Python calls PyState_AddModule automatically after importing a module that uses
, so it is unnecessary (but harmless) to call it from module initialization code. An explicit call is needed only if the module’s own init code subsequently calls PyState_FindModule. The function is mainly intended for implementing alternative import mechanisms (either by calling it directly, or by referring to its implementation for details of the required state updates).
If a module was attached previously using the same def, it is replaced by the new module.
The caller must have an
.
Return -1 with an exception set on error, 0 on success.
Added in version 3.3.
intPyState_RemoveModule(
*def)
Part of the
since version 3.3.Removes the module object created from def from the interpreter state. Return -1 with an exception set on error, 0 on success.
The caller must have an
.
Added in version 3.3.