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 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.

CONFORMING TO

       These functions are GNU extensions.

NOTES

       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 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

       This page is part of release 3.54 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)