MALLOC_GET_STATE(3) Linux Programmer's Manual MALLOC_GET_STATE(3)NAME
malloc_get_state, malloc_set_state - record and restore state of malloc
implementation
SYNOPSIS
#include <stdlib.h>
void* malloc_get_state(void);
int malloc_set_state(void *state);
DESCRIPTION
The malloc_get_state() function records the current state of all mal‐
loc(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.
CONFORMING TO
These functions are GNU extensions.
NOTES
These functions are especially useful when using this malloc(3) imple‐
mentation as part of a shared library, and the heap contents are
saved/restored via some other method. This technique is used by the
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 mal‐
loc 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 ALSOmalloc(3), mallopt(3)COLOPHON
This page is part of release 3.65 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2012-05-04 MALLOC_GET_STATE(3)
