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- /* An arena-like memory interface for the compiler.
- */
- #ifndef Py_LIMITED_API
- #ifndef Py_PYARENA_H
- #define Py_PYARENA_H
- #ifdef __cplusplus
- extern "C" {
- #endif
- typedef struct _arena PyArena;
- /* PyArena_New() and PyArena_Free() create a new arena and free it,
- respectively. Once an arena has been created, it can be used
- to allocate memory via PyArena_Malloc(). Pointers to PyObject can
- also be registered with the arena via PyArena_AddPyObject(), and the
- arena will ensure that the PyObjects stay alive at least until
- PyArena_Free() is called. When an arena is freed, all the memory it
- allocated is freed, the arena releases internal references to registered
- PyObject*, and none of its pointers are valid.
- XXX (tim) What does "none of its pointers are valid" mean? Does it
- XXX mean that pointers previously obtained via PyArena_Malloc() are
- XXX no longer valid? (That's clearly true, but not sure that's what
- XXX the text is trying to say.)
- PyArena_New() returns an arena pointer. On error, it
- returns a negative number and sets an exception.
- XXX (tim): Not true. On error, PyArena_New() actually returns NULL,
- XXX and looks like it may or may not set an exception (e.g., if the
- XXX internal PyList_New(0) returns NULL, PyArena_New() passes that on
- XXX and an exception is set; OTOH, if the internal
- XXX block_new(DEFAULT_BLOCK_SIZE) returns NULL, that's passed on but
- XXX an exception is not set in that case).
- */
- PyAPI_FUNC(PyArena *) PyArena_New(void);
- PyAPI_FUNC(void) PyArena_Free(PyArena *);
- /* Mostly like malloc(), return the address of a block of memory spanning
- * `size` bytes, or return NULL (without setting an exception) if enough
- * new memory can't be obtained. Unlike malloc(0), PyArena_Malloc() with
- * size=0 does not guarantee to return a unique pointer (the pointer
- * returned may equal one or more other pointers obtained from
- * PyArena_Malloc()).
- * Note that pointers obtained via PyArena_Malloc() must never be passed to
- * the system free() or realloc(), or to any of Python's similar memory-
- * management functions. PyArena_Malloc()-obtained pointers remain valid
- * until PyArena_Free(ar) is called, at which point all pointers obtained
- * from the arena `ar` become invalid simultaneously.
- */
- PyAPI_FUNC(void *) PyArena_Malloc(PyArena *, size_t size);
- /* This routine isn't a proper arena allocation routine. It takes
- * a PyObject* and records it so that it can be DECREFed when the
- * arena is freed.
- */
- PyAPI_FUNC(int) PyArena_AddPyObject(PyArena *, PyObject *);
- #ifdef __cplusplus
- }
- #endif
- #endif /* !Py_PYARENA_H */
- #endif /* Py_LIMITED_API */
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