MALLOC_GET_STATE(3) Linux Programmer's Manual MALLOC_GET_STATE(3)
malloc_get_state, malloc_set_state - record and restore state of malloc implementation
int malloc_set_state(void *state);
The malloc_get_state() function records the current state of all malloc(3) internal book-
keeping 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.
On success, malloc_get_state() returns a pointer to a newly allocated opaque data struc-
ture. On error (for example, memory could not be allocated for the data structure), mal-
loc_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.
These functions are especially 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 the GNU Emacs to implement its "dumping" function.
Hook function pointers are never saved or restored by these functions, with two excep-
tions: 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.
This page is part of release 3.55 of the Linux man-pages project. A description of the
project, and information about reporting bugs, can be found at
GNU 2012-05-04 MALLOC_GET_STATE(3)