NAME¶
malloc_get_state, malloc_set_state - record and restore state of malloc
implementation
SYNOPSIS¶
#include <malloc.h>
void* malloc_get_state(void);
int malloc_set_state(void *state);
DESCRIPTION¶
The
malloc_get_state() function records the current state of all
malloc(3) internal bookkeeping variables (but not the actual contents
of the heap or the state of
malloc_hook(3) functions pointers). The
state is recorded in a system-dependent opaque data structure dynamically
allocated via
malloc(3), and a pointer to that data structure is
returned as the function result. (It is the caller's responsibility to
free(3) this memory.)
The
malloc_set_state() function restores the state of all
malloc(3) internal bookkeeping variables to the values recorded in the
opaque data structure pointed to by
state.
RETURN VALUE¶
On success,
malloc_get_state() returns a pointer to a newly allocated
opaque data structure. On error (for example, memory could not be allocated
for the data structure),
malloc_get_state() returns NULL.
On success,
malloc_set_state() returns 0. If the implementation detects
that
state does not point to a correctly formed data structure,
malloc_set_state() returns -1. If the implementation detects that the
version of the data structure referred to by
state is a more recent
version than this implementation knows about,
malloc_set_state()
returns -2.
These functions are GNU extensions.
NOTES¶
These functions are useful when using this
malloc(3) implementation as
part of a shared library, and the heap contents are saved/restored via some
other method. This technique is used by GNU Emacs to implement its
"dumping" function.
Hook function pointers are never saved or restored by these functions, with two
exceptions: if malloc checking (see
mallopt(3)) was in use when
malloc_get_state() was called, then
malloc_set_state() resets
malloc checking hooks if possible; if malloc checking was not in use in the
recorded state, but the caller has requested malloc checking, then the hooks
are reset to 0.
SEE ALSO¶
malloc(3),
mallopt(3)
COLOPHON¶
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description of the project, information about reporting bugs, and the latest
version of this page, can be found at
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