mirror of
https://github.com/python/cpython.git
synced 2024-11-27 20:04:41 +08:00
316 lines
12 KiB
ReStructuredText
316 lines
12 KiB
ReStructuredText
.. highlightlang:: c
|
|
|
|
.. _importing:
|
|
|
|
Importing Modules
|
|
=================
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ImportModule(const char *name)
|
|
|
|
.. index::
|
|
single: package variable; __all__
|
|
single: __all__ (package variable)
|
|
single: modules (in module sys)
|
|
|
|
This is a simplified interface to :c:func:`PyImport_ImportModuleEx` below,
|
|
leaving the *globals* and *locals* arguments set to *NULL* and *level* set
|
|
to 0. When the *name*
|
|
argument contains a dot (when it specifies a submodule of a package), the
|
|
*fromlist* argument is set to the list ``['*']`` so that the return value is the
|
|
named module rather than the top-level package containing it as would otherwise
|
|
be the case. (Unfortunately, this has an additional side effect when *name* in
|
|
fact specifies a subpackage instead of a submodule: the submodules specified in
|
|
the package's ``__all__`` variable are loaded.) Return a new reference to the
|
|
imported module, or *NULL* with an exception set on failure. A failing
|
|
import of a module doesn't leave the module in :data:`sys.modules`.
|
|
|
|
This function always uses absolute imports.
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ImportModuleNoBlock(const char *name)
|
|
|
|
This function is a deprecated alias of :c:func:`PyImport_ImportModule`.
|
|
|
|
.. versionchanged:: 3.3
|
|
This function used to fail immediately when the import lock was held
|
|
by another thread. In Python 3.3 though, the locking scheme switched
|
|
to per-module locks for most purposes, so this function's special
|
|
behaviour isn't needed anymore.
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ImportModuleEx(const char *name, PyObject *globals, PyObject *locals, PyObject *fromlist)
|
|
|
|
.. index:: builtin: __import__
|
|
|
|
Import a module. This is best described by referring to the built-in Python
|
|
function :func:`__import__`.
|
|
|
|
The return value is a new reference to the imported module or top-level
|
|
package, or *NULL* with an exception set on failure. Like for
|
|
:func:`__import__`, the return value when a submodule of a package was
|
|
requested is normally the top-level package, unless a non-empty *fromlist*
|
|
was given.
|
|
|
|
Failing imports remove incomplete module objects, like with
|
|
:c:func:`PyImport_ImportModule`.
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ImportModuleLevelObject(PyObject *name, PyObject *globals, PyObject *locals, PyObject *fromlist, int level)
|
|
|
|
Import a module. This is best described by referring to the built-in Python
|
|
function :func:`__import__`, as the standard :func:`__import__` function calls
|
|
this function directly.
|
|
|
|
The return value is a new reference to the imported module or top-level package,
|
|
or *NULL* with an exception set on failure. Like for :func:`__import__`,
|
|
the return value when a submodule of a package was requested is normally the
|
|
top-level package, unless a non-empty *fromlist* was given.
|
|
|
|
.. versionadded:: 3.3
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ImportModuleLevel(const char *name, PyObject *globals, PyObject *locals, PyObject *fromlist, int level)
|
|
|
|
Similar to :c:func:`PyImport_ImportModuleLevelObject`, but the name is a
|
|
UTF-8 encoded string instead of a Unicode object.
|
|
|
|
.. versionchanged:: 3.3
|
|
Negative values for *level* are no longer accepted.
|
|
|
|
.. c:function:: PyObject* PyImport_Import(PyObject *name)
|
|
|
|
This is a higher-level interface that calls the current "import hook
|
|
function" (with an explicit *level* of 0, meaning absolute import). It
|
|
invokes the :func:`__import__` function from the ``__builtins__`` of the
|
|
current globals. This means that the import is done using whatever import
|
|
hooks are installed in the current environment.
|
|
|
|
This function always uses absolute imports.
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ReloadModule(PyObject *m)
|
|
|
|
Reload a module. Return a new reference to the reloaded module, or *NULL* with
|
|
an exception set on failure (the module still exists in this case).
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_AddModuleObject(PyObject *name)
|
|
|
|
Return the module object corresponding to a module name. The *name* argument
|
|
may be of the form ``package.module``. First check the modules dictionary if
|
|
there's one there, and if not, create a new one and insert it in the modules
|
|
dictionary. Return *NULL* with an exception set on failure.
|
|
|
|
.. note::
|
|
|
|
This function does not load or import the module; if the module wasn't already
|
|
loaded, you will get an empty module object. Use :c:func:`PyImport_ImportModule`
|
|
or one of its variants to import a module. Package structures implied by a
|
|
dotted name for *name* are not created if not already present.
|
|
|
|
.. versionadded:: 3.3
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_AddModule(const char *name)
|
|
|
|
Similar to :c:func:`PyImport_AddModuleObject`, but the name is a UTF-8
|
|
encoded string instead of a Unicode object.
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ExecCodeModule(const char *name, PyObject *co)
|
|
|
|
.. index:: builtin: compile
|
|
|
|
Given a module name (possibly of the form ``package.module``) and a code object
|
|
read from a Python bytecode file or obtained from the built-in function
|
|
:func:`compile`, load the module. Return a new reference to the module object,
|
|
or *NULL* with an exception set if an error occurred. *name*
|
|
is removed from :attr:`sys.modules` in error cases, even if *name* was already
|
|
in :attr:`sys.modules` on entry to :c:func:`PyImport_ExecCodeModule`. Leaving
|
|
incompletely initialized modules in :attr:`sys.modules` is dangerous, as imports of
|
|
such modules have no way to know that the module object is an unknown (and
|
|
probably damaged with respect to the module author's intents) state.
|
|
|
|
The module's :attr:`__spec__` and :attr:`__loader__` will be set, if
|
|
not set already, with the appropriate values. The spec's loader will
|
|
be set to the module's ``__loader__`` (if set) and to an instance of
|
|
:class:`SourceFileLoader` otherwise.
|
|
|
|
The module's :attr:`__file__` attribute will be set to the code object's
|
|
:c:member:`co_filename`. If applicable, :attr:`__cached__` will also
|
|
be set.
|
|
|
|
This function will reload the module if it was already imported. See
|
|
:c:func:`PyImport_ReloadModule` for the intended way to reload a module.
|
|
|
|
If *name* points to a dotted name of the form ``package.module``, any package
|
|
structures not already created will still not be created.
|
|
|
|
See also :c:func:`PyImport_ExecCodeModuleEx` and
|
|
:c:func:`PyImport_ExecCodeModuleWithPathnames`.
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ExecCodeModuleEx(const char *name, PyObject *co, const char *pathname)
|
|
|
|
Like :c:func:`PyImport_ExecCodeModule`, but the :attr:`__file__` attribute of
|
|
the module object is set to *pathname* if it is non-``NULL``.
|
|
|
|
See also :c:func:`PyImport_ExecCodeModuleWithPathnames`.
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ExecCodeModuleObject(PyObject *name, PyObject *co, PyObject *pathname, PyObject *cpathname)
|
|
|
|
Like :c:func:`PyImport_ExecCodeModuleEx`, but the :attr:`__cached__`
|
|
attribute of the module object is set to *cpathname* if it is
|
|
non-``NULL``. Of the three functions, this is the preferred one to use.
|
|
|
|
.. versionadded:: 3.3
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_ExecCodeModuleWithPathnames(const char *name, PyObject *co, const char *pathname, const char *cpathname)
|
|
|
|
Like :c:func:`PyImport_ExecCodeModuleObject`, but *name*, *pathname* and
|
|
*cpathname* are UTF-8 encoded strings. Attempts are also made to figure out
|
|
what the value for *pathname* should be from *cpathname* if the former is
|
|
set to ``NULL``.
|
|
|
|
.. versionadded:: 3.2
|
|
.. versionchanged:: 3.3
|
|
Uses :func:`imp.source_from_cache()` in calculating the source path if
|
|
only the bytecode path is provided.
|
|
|
|
|
|
.. c:function:: long PyImport_GetMagicNumber()
|
|
|
|
Return the magic number for Python bytecode files (a.k.a. :file:`.pyc` file).
|
|
The magic number should be present in the first four bytes of the bytecode
|
|
file, in little-endian byte order. Returns ``-1`` on error.
|
|
|
|
.. versionchanged:: 3.3
|
|
Return value of ``-1`` upon failure.
|
|
|
|
|
|
.. c:function:: const char * PyImport_GetMagicTag()
|
|
|
|
Return the magic tag string for :pep:`3147` format Python bytecode file
|
|
names. Keep in mind that the value at ``sys.implementation.cache_tag`` is
|
|
authoritative and should be used instead of this function.
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
.. c:function:: PyObject* PyImport_GetModuleDict()
|
|
|
|
Return the dictionary used for the module administration (a.k.a.
|
|
``sys.modules``). Note that this is a per-interpreter variable.
|
|
|
|
|
|
.. c:function:: PyObject* PyImport_GetImporter(PyObject *path)
|
|
|
|
Return a finder object for a :data:`sys.path`/:attr:`pkg.__path__` item
|
|
*path*, possibly by fetching it from the :data:`sys.path_importer_cache`
|
|
dict. If it wasn't yet cached, traverse :data:`sys.path_hooks` until a hook
|
|
is found that can handle the path item. Return ``None`` if no hook could;
|
|
this tells our caller that the :term:`path based finder` could not find a
|
|
finder for this path item. Cache the result in :data:`sys.path_importer_cache`.
|
|
Return a new reference to the finder object.
|
|
|
|
|
|
.. c:function:: void _PyImport_Init()
|
|
|
|
Initialize the import mechanism. For internal use only.
|
|
|
|
|
|
.. c:function:: void PyImport_Cleanup()
|
|
|
|
Empty the module table. For internal use only.
|
|
|
|
|
|
.. c:function:: void _PyImport_Fini()
|
|
|
|
Finalize the import mechanism. For internal use only.
|
|
|
|
|
|
.. c:function:: PyObject* _PyImport_FindExtension(char *, char *)
|
|
|
|
For internal use only.
|
|
|
|
|
|
.. c:function:: int PyImport_ImportFrozenModuleObject(PyObject *name)
|
|
|
|
Load a frozen module named *name*. Return ``1`` for success, ``0`` if the
|
|
module is not found, and ``-1`` with an exception set if the initialization
|
|
failed. To access the imported module on a successful load, use
|
|
:c:func:`PyImport_ImportModule`. (Note the misnomer --- this function would
|
|
reload the module if it was already imported.)
|
|
|
|
.. versionadded:: 3.3
|
|
|
|
.. versionchanged:: 3.4
|
|
The ``__file__`` attribute is no longer set on the module.
|
|
|
|
|
|
.. c:function:: int PyImport_ImportFrozenModule(const char *name)
|
|
|
|
Similar to :c:func:`PyImport_ImportFrozenModuleObject`, but the name is a
|
|
UTF-8 encoded string instead of a Unicode object.
|
|
|
|
|
|
.. c:type:: struct _frozen
|
|
|
|
.. index:: single: freeze utility
|
|
|
|
This is the structure type definition for frozen module descriptors, as
|
|
generated by the :program:`freeze` utility (see :file:`Tools/freeze/` in the
|
|
Python source distribution). Its definition, found in :file:`Include/import.h`,
|
|
is::
|
|
|
|
struct _frozen {
|
|
char *name;
|
|
unsigned char *code;
|
|
int size;
|
|
};
|
|
|
|
|
|
.. c:var:: const struct _frozen* PyImport_FrozenModules
|
|
|
|
This pointer is initialized to point to an array of :c:type:`struct _frozen`
|
|
records, terminated by one whose members are all *NULL* or zero. When a frozen
|
|
module is imported, it is searched in this table. Third-party code could play
|
|
tricks with this to provide a dynamically created collection of frozen modules.
|
|
|
|
|
|
.. c:function:: int PyImport_AppendInittab(const char *name, PyObject* (*initfunc)(void))
|
|
|
|
Add a single module to the existing table of built-in modules. This is a
|
|
convenience wrapper around :c:func:`PyImport_ExtendInittab`, returning ``-1`` if
|
|
the table could not be extended. The new module can be imported by the name
|
|
*name*, and uses the function *initfunc* as the initialization function called
|
|
on the first attempted import. This should be called before
|
|
:c:func:`Py_Initialize`.
|
|
|
|
|
|
.. c:type:: struct _inittab
|
|
|
|
Structure describing a single entry in the list of built-in modules. Each of
|
|
these structures gives the name and initialization function for a module built
|
|
into the interpreter. The name is an ASCII encoded string. Programs which
|
|
embed Python may use an array of these structures in conjunction with
|
|
:c:func:`PyImport_ExtendInittab` to provide additional built-in modules.
|
|
The structure is defined in :file:`Include/import.h` as::
|
|
|
|
struct _inittab {
|
|
char *name; /* ASCII encoded string */
|
|
PyObject* (*initfunc)(void);
|
|
};
|
|
|
|
|
|
.. c:function:: int PyImport_ExtendInittab(struct _inittab *newtab)
|
|
|
|
Add a collection of modules to the table of built-in modules. The *newtab*
|
|
array must end with a sentinel entry which contains *NULL* for the :attr:`name`
|
|
field; failure to provide the sentinel value can result in a memory fault.
|
|
Returns ``0`` on success or ``-1`` if insufficient memory could be allocated to
|
|
extend the internal table. In the event of failure, no modules are added to the
|
|
internal table. This should be called before :c:func:`Py_Initialize`.
|