Doc/c-api/module.rst
.. highlight:: c
.. _moduleobjects:
.. index:: pair: object; module
.. c:var:: PyTypeObject PyModule_Type
.. index:: single: ModuleType (in module types)
This instance of :c:type:PyTypeObject represents the Python module type. This
is exposed to Python programs as :py:class:types.ModuleType.
.. c:function:: int PyModule_Check(PyObject *p)
Return true if p is a module object, or a subtype of a module object. This function always succeeds.
.. c:function:: int PyModule_CheckExact(PyObject *p)
Return true if p is a module object, but not a subtype of
:c:data:PyModule_Type. This function always succeeds.
.. c:function:: PyObject* PyModule_NewObject(PyObject *name)
.. index:: single: name (module attribute) single: doc (module attribute) single: file (module attribute) single: package (module attribute) single: loader (module attribute)
Return a new module object with :attr:module.__name__ set to name.
The module's :attr:!__name__, :attr:~module.__doc__,
:attr:~module.__package__ and :attr:~module.__loader__ attributes are
filled in (all but :attr:!__name__ are set to None). The caller is
responsible for setting a :attr:~module.__file__ attribute.
Return NULL with an exception set on error.
.. versionadded:: 3.3
.. versionchanged:: 3.4
:attr:~module.__package__ and :attr:~module.__loader__ are now set to
None.
.. c:function:: PyObject* PyModule_New(const char *name)
Similar to :c:func:PyModule_NewObject, but the name is a UTF-8 encoded
string instead of a Unicode object.
.. c:function:: 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:~object.__dict__ attribute of the module object.
If module is not a module object (or a subtype of a module object),
:exc:SystemError is raised and NULL is returned.
It is recommended extensions use other PyModule_* and
PyObject_* functions rather than directly manipulate a module's
:attr:~object.__dict__.
The returned reference is borrowed from the module; it is valid until the module is destroyed.
.. c:function:: PyObject* PyModule_GetNameObject(PyObject *module)
.. index:: single: name (module attribute) single: SystemError (built-in exception)
Return module's :attr:~module.__name__ value. If the module does not
provide one, or if it is not a string, :exc:SystemError is raised and
NULL is returned.
.. versionadded:: 3.3
.. c:function:: const char* PyModule_GetName(PyObject *module)
Similar to :c:func:PyModule_GetNameObject 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 :py:attr:~module.__name__
attribute.
.. c:function:: PyModuleDef* PyModule_GetDef(PyObject *module)
Return a pointer to the :c:type:PyModuleDef 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 :c:func:PyErr_Occurred to tell this case apart from a missing
:c:type:!PyModuleDef.
.. c:function:: PyObject* PyModule_GetFilenameObject(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:~module.__file__ attribute. If this is not defined, or if it is not a
string, raise :exc:SystemError and return NULL; otherwise return
a reference to a Unicode object.
.. versionadded:: 3.2
.. c:function:: const char* PyModule_GetFilename(PyObject *module)
Similar to :c:func:PyModule_GetFilenameObject but return the filename
encoded to 'utf-8'.
The returned buffer is only valid until the module's :py:attr:~module.__file__ attribute
is reassigned or the module is destroyed.
.. deprecated:: 3.2
:c:func:PyModule_GetFilename raises :exc:UnicodeEncodeError on
unencodable filenames, use :c:func:PyModule_GetFilenameObject instead.
.. _pymoduledef_slot:
Modules created using the C API are typically defined using an
array of :dfn:slots.
The slots provide a "description" of how a module should be created.
.. versionchanged:: 3.15
Previously, a :c:type:PyModuleDef struct was necessary to define modules.
The older way of defining modules is still available: consult either the
:ref:pymoduledef section or earlier versions of this documentation
if you plan to support earlier Python versions.
The slots array is usually used to define an extension module's “main”
module object (see :ref:extension-modules for details).
It can also be used to
:ref:create extension modules dynamically <module-from-slots>.
Unless specified otherwise, the same slot ID may not be repeated in an array of slots.
.. c:type:: PyModuleDef_Slot
.. c:member:: int slot
A slot ID, chosen from the available ``Py_mod_*`` values explained below.
An ID of 0 marks the end of a :c:type:`!PyModuleDef_Slot` array.
.. c:member:: void* value
Value of the slot, whose meaning depends on the slot ID.
The value may not be NULL.
To leave a slot out, omit the :c:type:`PyModuleDef_Slot` entry entirely.
.. versionadded:: 3.5
Metadata slots ..............
.. c:macro:: Py_mod_name
:c:type:Slot ID <PyModuleDef_Slot.slot> for the name of the new module,
as a NUL-terminated UTF8-encoded const char *.
Note that modules are typically created using a
:py:class:~importlib.machinery.ModuleSpec, and when they are, the
name from the spec will be used instead of :c:data:!Py_mod_name.
However, it is still recommended to include this slot for introspection
and debugging purposes.
.. versionadded:: 3.15
Use :c:member:`PyModuleDef.m_name` instead to support previous versions.
.. c:macro:: Py_mod_doc
:c:type:Slot ID <PyModuleDef_Slot.slot> for the docstring of the new
module, as a NUL-terminated UTF8-encoded const char *.
Usually it is set to a variable created with :c:macro:PyDoc_STRVAR.
.. versionadded:: 3.15
Use :c:member:`PyModuleDef.m_doc` instead to support previous versions.
Feature slots .............
.. c:macro:: Py_mod_abi
:c:type:Slot ID <PyModuleDef_Slot.slot> whose value points to
a :c:struct:PyABIInfo structure describing the ABI that
the extension is using.
A suitable :c:struct:!PyABIInfo variable can be defined using the
:c:macro:PyABIInfo_VAR macro, as in:
.. code-block:: c
PyABIInfo_VAR(abi_info);
static PyModuleDef_Slot mymodule_slots[] = {
{Py_mod_abi, &abi_info},
...
};
When creating a module, Python checks the value of this slot
using :c:func:PyABIInfo_Check.
This slot is required, except for modules created from
:c:struct:PyModuleDef.
.. versionadded:: 3.15
.. c:macro:: Py_mod_multiple_interpreters
:c:type:Slot ID <PyModuleDef_Slot.slot> whose value is one of:
.. c:namespace:: NULL
.. c:macro:: Py_MOD_MULTIPLE_INTERPRETERS_NOT_SUPPORTED
The module does not support being imported in subinterpreters.
.. c:macro:: Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED
The module supports being imported in subinterpreters,
but only when they share the main interpreter's GIL.
(See :ref:`isolating-extensions-howto`.)
.. c:macro:: Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
The module supports being imported in subinterpreters,
even when they have their own GIL.
(See :ref:`isolating-extensions-howto`.)
This slot determines whether or not importing this module in a subinterpreter will fail.
If Py_mod_multiple_interpreters is not specified, the import
machinery defaults to Py_MOD_MULTIPLE_INTERPRETERS_SUPPORTED.
.. versionadded:: 3.12
.. c:macro:: Py_mod_gil
:c:type:Slot ID <PyModuleDef_Slot.slot> whose value is one of:
.. c:namespace:: NULL
.. c:macro:: Py_MOD_GIL_USED
The module depends on the presence of the global interpreter lock (GIL),
and may access global state without synchronization.
.. c:macro:: 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
:option:--disable-gil. Otherwise, it determines whether or not importing
this module will cause the GIL to be automatically enabled. See
:ref:whatsnew313-free-threaded-cpython for more detail.
If Py_mod_gil is not specified, the import machinery defaults to
Py_MOD_GIL_USED.
.. versionadded:: 3.13
Creation and initialization slots .................................
.. c:macro:: Py_mod_create
:c:type:Slot ID <PyModuleDef_Slot.slot> for a function that creates
the module object itself.
The function must have the signature:
.. c:function:: PyObject* create_module(PyObject *spec, PyModuleDef *def) :no-index-entry: :no-contents-entry:
The function will be called with:
ModuleSpec-like object, meaning that any attributes defined
for :py:class:importlib.machinery.ModuleSpec have matching semantics.
However, any of the attributes may be missing.NULL, or the module definition if the module is created from one.The function 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.
If Py_mod_create is not specified, the import machinery will create
a normal module object using :c:func:PyModule_New. 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
:c:type:PyModule_Type.
However, some slots may only be used with
:c:type:!PyModule_Type instances; in particular:
Py_mod_exec,module state slots <ext-module-state-slots> (Py_mod_state_*),Py_mod_token... versionadded:: 3.5
.. versionchanged:: 3.15
The *slots* argument may be a ``ModuleSpec``-like object, rather than
a true :py:class:`~importlib.machinery.ModuleSpec` instance.
Note that previous versions of CPython did not enforce this.
The *def* argument may now be ``NULL``, since modules are not necessarily
made from definitions.
.. c:macro:: Py_mod_exec
:c:type:Slot ID <PyModuleDef_Slot.slot> for a function that will
:dfn:execute, or initialize, the module.
This function does the equivalent to executing the code of a Python module:
typically, it adds classes and constants to the module.
The signature of the function is:
.. c:function:: int exec_module(PyObject* module) :no-index-entry: :no-contents-entry:
See the :ref:capi-module-support-functions section for some useful
functions to call.
For backwards compatibility, the :c:type:PyModuleDef.m_slots array may
contain multiple :c:macro:!Py_mod_exec slots; these are processed in the
order they appear in the array.
Elsewhere (that is, in arguments to :c:func:PyModule_FromSlotsAndSpec
and in return values of :samp:PyModExport_{<name>}), repeating the slot
is not allowed.
.. versionadded:: 3.5
.. versionchanged:: 3.15
Repeated ``Py_mod_exec`` slots are disallowed, except in
:c:type:`PyModuleDef.m_slots`.
.. c:macro:: Py_mod_methods
:c:type:Slot ID <PyModuleDef_Slot.slot> for a table of module-level
functions, as an array of :c:type:PyMethodDef values suitable as the
functions argument to :c:func:PyModule_AddFunctions.
Like other slot IDs, a slots array may only contain one
:c:macro:!Py_mod_methods entry.
To add functions from multiple :c:type:PyMethodDef arrays, call
:c:func:PyModule_AddFunctions in the :c:macro:Py_mod_exec function.
The table must be statically allocated (or otherwise guaranteed to outlive the module object).
.. versionadded:: 3.15
Use :c:member:`PyModuleDef.m_methods` instead to support previous versions.
.. _ext-module-state:
Extension modules can have module state -- a
piece of memory that is allocated on module creation,
and freed when the module object is deallocated.
The module state is specified using :ref:dedicated slots <ext-module-state-slots>.
A typical use of module state is storing an exception type -- or indeed any type object defined by the module --
Unlike the module's Python attributes, Python code cannot replace or delete data stored in module state.
Keeping per-module information in attributes and module state, rather than in static globals, makes module objects isolated and safer for use in multiple sub-interpreters. It also helps Python do an orderly clean-up when it shuts down.
Extensions that keep references to Python objects as part of module state must
implement :c:macro:Py_mod_state_traverse and :c:macro:Py_mod_state_clear
functions to avoid reference leaks.
To retrieve the state from a given module, use the following functions:
.. c:function:: 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
:c:macro:Py_mod_state_size.
On error, return NULL with an exception set.
Use :c:func:PyErr_Occurred to tell this case apart from missing
module state.
.. c:function:: int PyModule_GetStateSize(PyObject *module, Py_ssize_t *result)
Set *result to the size of module's state, as specified
using :c:macro:Py_mod_state_size (or :c:member:PyModuleDef.m_size),
and return 0.
On error, set *result to -1, and return -1 with an exception set.
.. versionadded:: 3.15
.. _ext-module-state-slots:
Slots for defining module state ...............................
The following :c:member:PyModuleDef_Slot.slot IDs are available for
defining the module state.
.. c:macro:: Py_mod_state_size
:c:type:Slot ID <PyModuleDef_Slot.slot> for the size of the module state,
in bytes.
Setting the value 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.
See :PEP:3121 for more details.
Use :c:func:PyModule_GetStateSize to retrieve the size of a given module.
.. versionadded:: 3.15
Use :c:member:`PyModuleDef.m_size` instead to support previous versions.
.. c:macro:: Py_mod_state_traverse
:c:type:Slot ID <PyModuleDef_Slot.slot> for a traversal function to call
during GC traversal of the module object.
The signature of the function, and meanings of the arguments,
is similar as for :c:member:PyTypeObject.tp_traverse:
.. c:function:: int traverse_module_state(PyObject *module, visitproc visit, void *arg) :no-index-entry: :no-contents-entry:
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 (:c:data:Py_mod_exec function). More
precisely, this function is not called if the state size
(:c:data:Py_mod_state_size) is greater than 0 and the module state
(as returned by :c:func:PyModule_GetState) is NULL.
.. versionadded:: 3.15
Use :c:member:`PyModuleDef.m_size` instead to support previous versions.
.. c:macro:: Py_mod_state_clear
:c:type:Slot ID <PyModuleDef_Slot.slot> for a clear function to call
during GC clearing of the module object.
The signature of the function is:
.. c:function:: int clear_module_state(PyObject* module) :no-index-entry: :no-contents-entry:
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 (:c:data:Py_mod_exec function). More
precisely, this function is not called if the state size
(:c:data:Py_mod_state_size) is greater than 0 and the module state
(as returned by :c:func:PyModule_GetState) is NULL.
Like :c:member:PyTypeObject.tp_clear, 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
the :c:macro:Py_mod_state_free function is called directly.
.. versionadded:: 3.15
Use :c:member:`PyModuleDef.m_clear` instead to support previous versions.
.. c:macro:: Py_mod_state_free
:c:type:Slot ID <PyModuleDef_Slot.slot> for a function to call during
deallocation of the module object.
The signature of the function is:
.. c:function:: int free_module_state(PyObject* module) :no-index-entry: :no-contents-entry:
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 (:c:data:Py_mod_exec function). More
precisely, this function is not called if the state size
(:c:data:Py_mod_state_size) is greater than 0 and the module state
(as returned by :c:func:PyModule_GetState) is NULL.
.. versionadded:: 3.15
Use :c:member:`PyModuleDef.m_free` instead to support previous versions.
.. _ext-module-token:
Module token ............
Each module may have an associated token: a pointer-sized value intended to identify of the module state's memory layout. This means that if you have a module object, but you are not sure if it “belongs” to your extension, you can check using code like this:
.. code-block:: c
PyObject *module = <the module in question>
void *module_token; if (PyModule_GetToken(module, &module_token) < 0) { return NULL; } if (module_token != your_token) { PyErr_SetString(PyExc_ValueError, "unexpected module") return NULL; }
// This module's state has the expected memory layout; it's safe to cast struct my_state state = (struct my_state*)PyModule_GetState(module)
A module's token -- and the your_token value to use in the above code -- is:
PyModuleDef: the address of that
:c:type:PyModuleDef;Py_mod_token slot: the value
of that slot;PyModExport_*
:ref:export hook <extension-export-hook>: the slots array that the export
hook returned (unless overridden with :c:macro:Py_mod_token)... c:macro:: Py_mod_token
:c:type:Slot ID <PyModuleDef_Slot.slot> for the module token.
If you use this slot to set the module token (rather than rely on the default), you must ensure that:
PyModuleDef struct, the module should
behave as if it was created from that :c:type:PyModuleDef.
In particular, the module state must have matching layout and semantics.Modules created from :c:type:PyModuleDef always use the address of
the :c:type:PyModuleDef as the token.
This means that :c:macro:!Py_mod_token cannot be used in
:c:member:PyModuleDef.m_slots.
.. versionadded:: 3.15
.. c:function:: int PyModule_GetToken(PyObject module, void* result)
Set *result to the module token for module and return 0.
On error, set *result to NULL, and return -1 with an exception set.
.. versionadded:: 3.15
See also :c:func:PyType_GetModuleByToken.
.. _module-from-slots:
The following functions may be used to create an extension module dynamically,
rather than from an extension's :ref:export hook <extension-export-hook>.
.. c:function:: PyObject *PyModule_FromSlotsAndSpec(const PyModuleDef_Slot *slots, PyObject *spec)
Create a new module object, given an array of :ref:slots <pymoduledef_slot>
and the :py:class:~importlib.machinery.ModuleSpec spec.
The slots argument must point to an array of :c:type:PyModuleDef_Slot
structures, terminated by an entry with slot ID of 0
(typically written as {0} or {0, NULL} in C).
The array must include a :c:data:Py_mod_abi entry.
The spec argument may be any ModuleSpec-like object, as described
in :c:macro:Py_mod_create documentation.
Currently, the spec must have a name attribute.
On success, return the new module.
On error, return NULL with an exception set.
Note that this does not process the module's execution slot
(:c:data:Py_mod_exec).
Both :c:func:!PyModule_FromSlotsAndSpec and :c:func:PyModule_Exec
must be called to fully initialize a module.
(See also :ref:multi-phase-initialization.)
The slots array only needs to be valid for the duration of the
:c:func:!PyModule_FromSlotsAndSpec call.
In particular, it may be heap-allocated.
.. versionadded:: 3.15
.. c:function:: int PyModule_Exec(PyObject *module)
Execute the :c:data:Py_mod_exec slot(s) of module.
On success, return 0. On error, return -1 with an exception set.
For clarity: If module has no slots, for example if it uses
:ref:legacy single-phase initialization <single-phase-initialization>,
this function does nothing and returns 0.
.. versionadded:: 3.15
.. _pymoduledef:
Traditionally, extension modules were defined using a module definition
as the “description" of how a module should be created.
Rather than using an array of :ref:slots <pymoduledef_slot> directly,
the definition has dedicated members for most common functionality,
and allows additional slots as an extension mechanism.
This way of defining modules is still available and there are no plans to remove it.
.. c:type:: PyModuleDef
The module definition struct, which holds 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 defined this way.
.. c:member:: PyModuleDef_Base m_base
Always initialize this member to :c:macro:`PyModuleDef_HEAD_INIT`:
.. c:namespace:: NULL
.. c:type:: PyModuleDef_Base
The type of :c:member:`!PyModuleDef.m_base`.
.. c:macro:: PyModuleDef_HEAD_INIT
The required initial value for :c:member:`!PyModuleDef.m_base`.
.. c:member:: const char *m_name
Corresponds to the :c:macro:`Py_mod_name` slot.
.. c:member:: const char *m_doc
These members correspond to the :c:macro:`Py_mod_doc` slot.
Setting this to NULL is equivalent to omitting the slot.
.. c:member:: Py_ssize_t m_size
Corresponds to the :c:macro:`Py_mod_state_size` slot.
Setting this to zero is equivalent to omitting the slot.
When using :ref:`legacy single-phase initialization <single-phase-initialization>`
or when creating modules dynamically using :c:func:`PyModule_Create`
or :c:func:`PyModule_Create2`, :c:member:`!m_size` may be set to -1.
This indicates that the module does not support sub-interpreters,
because it has global state.
.. c:member:: PyMethodDef *m_methods
Corresponds to the :c:macro:`Py_mod_methods` slot.
Setting this to NULL is equivalent to omitting the slot.
.. c:member:: PyModuleDef_Slot* m_slots
An array of additional slots, terminated by a ``{0, NULL}`` entry.
If the array contains slots corresponding to :c:type:`PyModuleDef`
members, the values must match.
For example, if you use :c:macro:`Py_mod_name` in :c:member:`!m_slots`,
:c:member:`PyModuleDef.m_name` must be set to the same pointer
(not just an equal string).
.. versionchanged:: 3.5
Prior to version 3.5, this member was always set to ``NULL``,
and was defined as:
.. c:member:: inquiry m_reload
.. c:member:: traverseproc m_traverse inquiry m_clear freefunc m_free
These members correspond to the :c:macro:`Py_mod_state_traverse`,
:c:macro:`Py_mod_state_clear`, and :c:macro:`Py_mod_state_free` slots,
respectively.
Setting these members to NULL is equivalent to omitting the
corresponding slots.
.. versionchanged:: 3.9
:c:member:`m_traverse`, :c:member:`m_clear` and :c:member:`m_free`
functions are no longer called before the module state is allocated.
.. c:var:: PyTypeObject PyModuleDef_Type
The type of PyModuleDef objects.
.. _moduledef-dynamic:
The following API can be used to create modules from a :c:type:!PyModuleDef
struct:
.. c:function:: PyObject* PyModule_Create(PyModuleDef *def)
Create a new module object, given the definition in def.
This is a macro that calls :c:func:PyModule_Create2 with
module_api_version set to :c:macro:PYTHON_API_VERSION, or
to :c:macro:PYTHON_ABI_VERSION if using the
:ref:limited API <limited-c-api>.
.. c:function:: PyObject* PyModule_Create2(PyModuleDef *def, int module_api_version)
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 :exc:RuntimeWarning is emitted.
Return NULL with an exception set on error.
This function does not support slots.
The :c:member:~PyModuleDef.m_slots member of def must be NULL.
.. note::
Most uses of this function should be using :c:func:`PyModule_Create`
instead; only use this if you are sure you need it.
.. c:function:: PyObject * PyModule_FromDefAndSpec(PyModuleDef *def, PyObject *spec)
This macro calls :c:func:PyModule_FromDefAndSpec2 with
module_api_version set to :c:macro:PYTHON_API_VERSION, or
to :c:macro:PYTHON_ABI_VERSION if using the
:ref:limited API <limited-c-api>.
.. versionadded:: 3.5
.. c:function:: PyObject * PyModule_FromDefAndSpec2(PyModuleDef *def, PyObject *spec, int module_api_version)
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 :exc:RuntimeWarning is emitted.
Return NULL with an exception set on error.
Note that this does not process execution slots (:c:data:Py_mod_exec).
Both PyModule_FromDefAndSpec and PyModule_ExecDef must be called
to fully initialize a module.
.. note::
Most uses of this function should be using :c:func:`PyModule_FromDefAndSpec`
instead; only use this if you are sure you need it.
.. versionadded:: 3.5
.. c:function:: int PyModule_ExecDef(PyObject *module, PyModuleDef *def)
Process any execution slots (:c:data:Py_mod_exec) given in def.
.. versionadded:: 3.5
.. c:macro:: PYTHON_API_VERSION PYTHON_API_STRING
The C API version, as an integer (1013) and string ("1013"), respectively.
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.
.. c:macro:: PYTHON_ABI_VERSION PYTHON_ABI_STRING
Defined as 3 and "3", respectively, 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.
.. _capi-module-support-functions:
The following functions are provided to help initialize a module object.
They are intended for a module's execution slot (:c:data:Py_mod_exec),
the initialization function for legacy :ref:single-phase initialization <single-phase-initialization>,
or code that creates modules dynamically.
.. c:function:: int PyModule_AddObjectRef(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.
On success, return 0. On error, raise an exception and return -1.
Example usage::
static int
add_spam(PyObject *module, int value)
{
PyObject *obj = PyLong_FromLong(value);
if (obj == NULL) {
return -1;
}
int res = PyModule_AddObjectRef(module, "spam", obj);
Py_DECREF(obj);
return res;
}
To be convenient, the function accepts NULL value 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::
static int
add_spam(PyObject *module, int value)
{
PyObject *obj = PyLong_FromLong(value);
int res = PyModule_AddObjectRef(module, "spam", obj);
Py_XDECREF(obj);
return res;
}
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
:c:func:PyUnicode_FromString and :c:func:PyObject_SetAttr directly.
For more details, see :c:func:PyUnicode_InternFromString, which may be
used internally to create a key object.
.. versionadded:: 3.10
.. c:function:: int PyModule_Add(PyObject *module, const char *name, PyObject *value)
Similar to :c:func:PyModule_AddObjectRef, but "steals" a reference
to value.
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) {
goto error;
}
.. versionadded:: 3.13
.. c:function:: int PyModule_AddObject(PyObject *module, const char *name, PyObject *value)
Similar to :c:func:PyModule_AddObjectRef, but steals a reference to
value on success (if it returns 0).
The new :c:func:PyModule_Add or :c:func:PyModule_AddObjectRef
functions are recommended, since it is
easy to introduce reference leaks by misusing the
:c:func:PyModule_AddObject function.
.. note::
Unlike other functions that steal references, ``PyModule_AddObject()``
only releases the reference to *value* **on success**.
This means that its return value must be checked, and calling code must
:c:func:`Py_XDECREF` *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);
goto error;
}
// PyModule_AddObject() stole a reference to obj:
// Py_XDECREF(obj) is not needed here.
.. deprecated:: 3.13
:c:func:`PyModule_AddObject` is :term:`soft deprecated`.
.. c:function:: 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 with an exception set on error, 0 on success.
This is a convenience function that calls :c:func:PyLong_FromLong and
:c:func:PyModule_AddObjectRef; see their documentation for details.
.. c:function:: 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 with an exception set on error, 0 on success.
This is a convenience function that calls
:c:func:PyUnicode_InternFromString and :c:func:PyModule_AddObjectRef;
see their documentation for details.
.. c:macro:: 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.
.. c:macro:: PyModule_AddStringMacro(module, macro)
Add a string constant to module.
.. c:function:: int PyModule_AddType(PyObject *module, PyTypeObject *type)
Add a type object to module.
The type object is finalized by calling internally :c:func:PyType_Ready.
The name of the type object is taken from the last component of
:c:member:~PyTypeObject.tp_name after dot.
Return -1 with an exception set on error, 0 on success.
.. versionadded:: 3.9
.. c:function:: int PyModule_AddFunctions(PyObject *module, PyMethodDef *functions)
Add the functions from the NULL terminated functions array to module.
Refer to the :c:type:PyMethodDef 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 :ref:multi-phase-initialization,
PyModule_Create, or PyModule_FromDefAndSpec).
Some module authors may prefer defining functions in multiple
:c:type:PyMethodDef 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).
.. versionadded:: 3.5
.. c:function:: int PyModule_SetDocString(PyObject *module, const char *docstring)
Set the docstring for module to docstring.
This function is called automatically when creating a module from
PyModuleDef (such as when using :ref:multi-phase-initialization,
PyModule_Create, or PyModule_FromDefAndSpec).
Return 0 on success.
Return -1 with an exception set on error.
.. versionadded:: 3.5
.. c:function:: int PyUnstable_Module_SetGIL(PyObject *module, void *gil)
Indicate that module does or does not support running without the global
interpreter lock (GIL), using one of the values from
:c:macro:Py_mod_gil. It must be called during module's initialization
function when using :ref: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
:option:--disable-gil.
Return -1 with an exception set on error, 0 on success.
.. versionadded:: 3.13
Module lookup (single-phase initialization) ...........................................
The legacy :ref:single-phase initialization <single-phase-initialization>
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.
.. c:function:: PyObject* PyState_FindModule(PyModuleDef *def)
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
:c:func:PyState_AddModule beforehand. In case the corresponding module object is not
found or has not been attached to the interpreter state yet, it returns NULL.
.. c:function:: int PyState_AddModule(PyObject *module, PyModuleDef *def)
Attaches the module object passed to the function to the interpreter state. This allows
the module object to be accessible via :c:func:PyState_FindModule.
Only effective on modules created using single-phase initialization.
Python calls PyState_AddModule automatically after importing a module
that uses :ref:single-phase initialization <single-phase-initialization>,
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 :term:attached thread state.
Return -1 with an exception set on error, 0 on success.
.. versionadded:: 3.3
.. c:function:: int PyState_RemoveModule(PyModuleDef *def)
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 :term:attached thread state.
.. versionadded:: 3.3