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 <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 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.

RETURN VALUE
       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.

CONFORMING TO
       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 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.

SEE ALSO
       malloc(3), mallopt(3)

COLOPHON
       This  page  is  part of release 3.74 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at http://www.kernel.org/doc/man-pages/.



GNU                                         2014-06-13                        MALLOC_GET_STATE(3)