mirror of https://github.com/python/cpython
166 lines
6.8 KiB
ReStructuredText
166 lines
6.8 KiB
ReStructuredText
.. highlight:: c
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.. index:: object; code, code object
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.. _codeobjects:
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Code Objects
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------------
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.. sectionauthor:: Jeffrey Yasskin <jyasskin@gmail.com>
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Code objects are a low-level detail of the CPython implementation.
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Each one represents a chunk of executable code that hasn't yet been
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bound into a function.
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.. c:type:: PyCodeObject
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The C structure of the objects used to describe code objects. The
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fields of this type are subject to change at any time.
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.. c:var:: PyTypeObject PyCode_Type
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This is an instance of :c:type:`PyTypeObject` representing the Python
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:class:`code` type.
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.. c:function:: int PyCode_Check(PyObject *co)
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Return true if *co* is a :class:`code` object. This function always succeeds.
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.. c:function:: int PyCode_GetNumFree(PyCodeObject *co)
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Return the number of free variables in *co*.
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.. c:function:: PyCodeObject* PyCode_New(int argcount, int kwonlyargcount, int nlocals, int stacksize, int flags, PyObject *code, PyObject *consts, PyObject *names, PyObject *varnames, PyObject *freevars, PyObject *cellvars, PyObject *filename, PyObject *name, int firstlineno, PyObject *linetable, PyObject *exceptiontable)
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Return a new code object. If you need a dummy code object to create a frame,
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use :c:func:`PyCode_NewEmpty` instead. Calling :c:func:`PyCode_New` directly
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will bind you to a precise Python version since the definition of the bytecode
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changes often. The many arguments of this function are inter-dependent in complex
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ways, meaning that subtle changes to values are likely to result in incorrect
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execution or VM crashes. Use this function only with extreme care.
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.. versionchanged:: 3.11
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Added ``exceptiontable`` parameter.
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.. c:function:: PyCodeObject* PyCode_NewWithPosOnlyArgs(int argcount, int posonlyargcount, int kwonlyargcount, int nlocals, int stacksize, int flags, PyObject *code, PyObject *consts, PyObject *names, PyObject *varnames, PyObject *freevars, PyObject *cellvars, PyObject *filename, PyObject *name, int firstlineno, PyObject *linetable, PyObject *exceptiontable)
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Similar to :c:func:`PyCode_New`, but with an extra "posonlyargcount" for positional-only arguments.
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The same caveats that apply to ``PyCode_New`` also apply to this function.
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.. versionadded:: 3.8
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.. versionchanged:: 3.11
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Added ``exceptiontable`` parameter.
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.. c:function:: PyCodeObject* PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
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Return a new empty code object with the specified filename,
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function name, and first line number. The resulting code
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object will raise an ``Exception`` if executed.
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.. c:function:: int PyCode_Addr2Line(PyCodeObject *co, int byte_offset)
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Return the line number of the instruction that occurs on or before ``byte_offset`` and ends after it.
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If you just need the line number of a frame, use :c:func:`PyFrame_GetLineNumber` instead.
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For efficiently iterating over the line numbers in a code object, use `the API described in PEP 626
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<https://peps.python.org/pep-0626/#out-of-process-debuggers-and-profilers>`_.
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.. c:function:: int PyCode_Addr2Location(PyObject *co, int byte_offset, int *start_line, int *start_column, int *end_line, int *end_column)
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Sets the passed ``int`` pointers to the source code line and column numbers
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for the instruction at ``byte_offset``. Sets the value to ``0`` when
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information is not available for any particular element.
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Returns ``1`` if the function succeeds and 0 otherwise.
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.. c:function:: PyObject* PyCode_GetCode(PyCodeObject *co)
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Equivalent to the Python code ``getattr(co, 'co_code')``.
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Returns a strong reference to a :c:type:`PyBytesObject` representing the
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bytecode in a code object. On error, ``NULL`` is returned and an exception
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is raised.
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This ``PyBytesObject`` may be created on-demand by the interpreter and does
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not necessarily represent the bytecode actually executed by CPython. The
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primary use case for this function is debuggers and profilers.
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.. versionadded:: 3.11
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.. c:function:: PyObject* PyCode_GetVarnames(PyCodeObject *co)
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Equivalent to the Python code ``getattr(co, 'co_varnames')``.
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Returns a new reference to a :c:type:`PyTupleObject` containing the names of
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the local variables. On error, ``NULL`` is returned and an exception
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is raised.
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.. versionadded:: 3.11
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.. c:function:: PyObject* PyCode_GetCellvars(PyCodeObject *co)
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Equivalent to the Python code ``getattr(co, 'co_cellvars')``.
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Returns a new reference to a :c:type:`PyTupleObject` containing the names of
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the local variables that are referenced by nested functions. On error, ``NULL``
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is returned and an exception is raised.
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.. versionadded:: 3.11
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.. c:function:: PyObject* PyCode_GetFreevars(PyCodeObject *co)
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Equivalent to the Python code ``getattr(co, 'co_freevars')``.
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Returns a new reference to a :c:type:`PyTupleObject` containing the names of
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the free variables. On error, ``NULL`` is returned and an exception is raised.
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.. versionadded:: 3.11
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.. c:function:: int PyCode_AddWatcher(PyCode_WatchCallback callback)
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Register *callback* as a code object watcher for the current interpreter.
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Return an ID which may be passed to :c:func:`PyCode_ClearWatcher`.
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In case of error (e.g. no more watcher IDs available),
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return ``-1`` and set an exception.
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.. versionadded:: 3.12
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.. c:function:: int PyCode_ClearWatcher(int watcher_id)
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Clear watcher identified by *watcher_id* previously returned from
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:c:func:`PyCode_AddWatcher` for the current interpreter.
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Return ``0`` on success, or ``-1`` and set an exception on error
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(e.g. if the given *watcher_id* was never registered.)
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.. versionadded:: 3.12
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.. c:type:: PyCodeEvent
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Enumeration of possible code object watcher events:
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- ``PY_CODE_EVENT_CREATE``
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- ``PY_CODE_EVENT_DESTROY``
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.. versionadded:: 3.12
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.. c:type:: int (*PyCode_WatchCallback)(PyCodeEvent event, PyCodeObject* co)
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Type of a code object watcher callback function.
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If *event* is ``PY_CODE_EVENT_CREATE``, then the callback is invoked
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after `co` has been fully initialized. Otherwise, the callback is invoked
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before the destruction of *co* takes place, so the prior state of *co*
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can be inspected.
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Users of this API should not rely on internal runtime implementation
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details. Such details may include, but are not limited to, the exact
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order and timing of creation and destruction of code objects. While
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changes in these details may result in differences observable by watchers
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(including whether a callback is invoked or not), it does not change
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the semantics of the Python code being executed.
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If the callback returns with an exception set, it must return ``-1``; this
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exception will be printed as an unraisable exception using
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:c:func:`PyErr_WriteUnraisable`. Otherwise it should return ``0``.
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.. versionadded:: 3.12
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