Importing Modules

Python documentation

PyObject

*PyImport_ImportModule(constchar*name)

Return value: New reference. Part of the

Stable ABI

.This is a wrapper around

PyImport_Import()

which takes a constchar* as an argument instead of a

PyObject

*.

PyObject

*PyImport_ImportModuleNoBlock(constchar*name)

Return value: New reference. Part of the

Stable ABI

.This function is a deprecated alias of

PyImport_ImportModule()

.

Changed in version 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.

Deprecated since version 3.13, will be removed in version 3.15: Use

PyImport_ImportModule()

instead.

PyObject

*PyImport_ImportModuleEx(constchar*name,

PyObject

*globals,

PyObject

*locals,

PyObject

*fromlist)

Return value: New reference.Import a module. This is best described by referring to the built-in Python function

__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

__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

PyImport_ImportModule()

.

PyObject

*PyImport_ImportModuleLevelObject(

PyObject

*name,

PyObject

*globals,

PyObject

*locals,

PyObject

*fromlist, intlevel)

Return value: New reference. Part of the

Stable ABI

since version 3.7.Import a module. This is best described by referring to the built-in Python function

__import__()

, as the standard __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

__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.

Added in version 3.3.

PyObject

*PyImport_ImportModuleLevel(constchar*name,

PyObject

*globals,

PyObject

*locals,

PyObject

*fromlist, intlevel)

Return value: New reference. Part of the

Stable ABI

.Similar to

PyImport_ImportModuleLevelObject()

, but the name is a UTF-8 encoded string instead of a Unicode object.

Changed in version 3.3: Negative values for level are no longer accepted.

PyObject

*PyImport_Import(

PyObject

*name)

Return value: New reference. Part of the

Stable ABI

.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

__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.

PyObject

*PyImport_ReloadModule(

PyObject

*m)

Return value: New reference. Part of the

Stable ABI

.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).

PyObject

*PyImport_AddModuleRef(constchar*name)

Return value: New reference. Part of the

Stable ABI

since version 3.13.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 a

strong reference

to the module on success. Return NULL with an exception set on failure.

The module name name is decoded from UTF-8.

This function does not load or import the module; if the module wasn’t already loaded, you will get an empty module object. Use

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.

Added in version 3.13.

PyObject

*PyImport_AddModuleObject(

PyObject

*name)

Return value: Borrowed reference. Part of the

Stable ABI

since version 3.7.Similar to

PyImport_AddModuleRef()

, but return a

borrowed reference

and name is a Python

str

object.

Added in version 3.3.

PyObject

*PyImport_AddModule(constchar*name)

Return value: Borrowed reference. Part of the

Stable ABI

.Similar to

PyImport_AddModuleRef()

, but return a

borrowed reference

.

PyObject

*PyImport_ExecCodeModule(constchar*name,

PyObject

*co)

Return value: New reference. Part of the

Stable ABI

.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

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

sys.modules

in error cases, even if name was already in sys.modules on entry to

PyImport_ExecCodeModule()

. Leaving incompletely initialized modules in 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

__spec__

and

__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

SourceFileLoader

otherwise.

The module’s

__file__

attribute will be set to the code object’s

co_filename

. If applicable,

__cached__

will also be set.

This function will reload the module if it was already imported. See

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

PyImport_ExecCodeModuleEx()

and

PyImport_ExecCodeModuleWithPathnames()

.

PyObject

*PyImport_ExecCodeModuleEx(constchar*name,

PyObject

*co, constchar*pathname)

Return value: New reference. Part of the

Stable ABI

.Like

PyImport_ExecCodeModule()

, but the

__file__

attribute of the module object is set to pathname if it is non-NULL.

See also

PyImport_ExecCodeModuleWithPathnames()

.

PyObject

*PyImport_ExecCodeModuleObject(

PyObject

*name,

PyObject

*co,

PyObject

*pathname,

PyObject

*cpathname)

Return value: New reference. Part of the

Stable ABI

since version 3.7.Like

PyImport_ExecCodeModuleEx()

, but the

__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.

Added in version 3.3.

Changed in version 3.12: Setting

__cached__

is deprecated. See

ModuleSpec

for alternatives.

PyObject

*PyImport_ExecCodeModuleWithPathnames(constchar*name,

PyObject

*co, constchar*pathname, constchar*cpathname)

Return value: New reference. Part of the

Stable ABI

.Like

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.

Added in version 3.2.

Changed in version 3.3: Uses imp.source_from_cache() in calculating the source path if only the bytecode path is provided.

Changed in version 3.12: No longer uses the removed imp module.

longPyImport_GetMagicNumber()

Part of the

Stable ABI

.Return the magic number for Python bytecode files (a.k.a. .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.

Changed in version 3.3: Return value of -1 upon failure.

constchar*PyImport_GetMagicTag()

Part of the

Stable ABI

.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.

Added in version 3.2.

PyObject

*PyImport_GetModuleDict()

Return value: Borrowed reference. Part of the

Stable ABI

.Return the dictionary used for the module administration (a.k.a. sys.modules). Note that this is a per-interpreter variable.

PyObject

*PyImport_GetModule(

PyObject

*name)

Return value: New reference. Part of the

Stable ABI

since version 3.8.Return the already imported module with the given name. If the module has not been imported yet then returns NULL but does not set an error. Returns NULL and sets an error if the lookup failed.

Added in version 3.7.

PyObject

*PyImport_GetImporter(

PyObject

*path)

Return value: New reference. Part of the

Stable ABI

.Return a finder object for a

sys.path

/pkg.__path__ item path, possibly by fetching it from the

sys.path_importer_cache

dict. If it wasn’t yet cached, traverse

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

path based finder

could not find a finder for this path item. Cache the result in sys.path_importer_cache. Return a new reference to the finder object.

intPyImport_ImportFrozenModuleObject(

PyObject

*name)

Part of the

Stable ABI

since version 3.7.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

PyImport_ImportModule()

. (Note the misnomer — this function would reload the module if it was already imported.)

Added in version 3.3.

Changed in version 3.4: The __file__ attribute is no longer set on the module.

intPyImport_ImportFrozenModule(constchar*name)

Part of the

Stable ABI

.Similar to

PyImport_ImportFrozenModuleObject()

, but the name is a UTF-8 encoded string instead of a Unicode object.

struct_frozen

This is the structure type definition for frozen module descriptors, as generated by the freeze utility (see Tools/freeze/ in the Python source distribution). Its definition, found in Include/import.h, is:

struct_frozen{constchar*name;constunsignedchar*code;intsize;boolis_package;};Changed in version 3.11: The new is_package field indicates whether the module is a package or not. This replaces setting the size field to a negative value.

conststruct

_frozen

*PyImport_FrozenModules

This pointer is initialized to point to an array of

_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.

intPyImport_AppendInittab(constchar*name,

PyObject

*(*initfunc)(void))

Part of the

Stable ABI

.Add a single module to the existing table of built-in modules. This is a convenience wrapper around

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

Py_Initialize()

.

struct_inittab

Structure describing a single entry in the list of built-in modules. Programs which embed Python may use an array of these structures in conjunction with

PyImport_ExtendInittab()

to provide additional built-in modules. The structure consists of two members:

constchar*name

The module name, as an ASCII encoded string.

PyObject

*(*initfunc)(void)

Initialization function for a module built into the interpreter.

intPyImport_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

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 must be called before

Py_Initialize()

.

If Python is initialized multiple times,

PyImport_AppendInittab()

or

PyImport_ExtendInittab()

must be called before each Python initialization.

struct

_inittab

*PyImport_Inittab

The table of built-in modules used by Python initialization. Do not use this directly; use

PyImport_AppendInittab()

and

PyImport_ExtendInittab()

instead.

PyObject

*PyImport_ImportModuleAttr(

PyObject

*mod_name,

PyObject

*attr_name)

Return value: New reference.Import the module mod_name and get its attribute attr_name.

Names must be Python

str

objects.

Helper function combining

PyImport_Import()

and

PyObject_GetAttr()

. For example, it can raise

ImportError

if the module is not found, and

AttributeError

if the attribute doesn’t exist.

Added in version 3.14.

PyObject

*PyImport_ImportModuleAttrString(constchar*mod_name, constchar*attr_name)

Return value: New reference.Similar to

PyImport_ImportModuleAttr()

, but names are UTF-8 encoded strings instead of Python

str

objects.

Added in version 3.14.