malloc_get_state

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
       Note: these function are removed in glibc version 2.25.

       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 al-
       located 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) in-
       ternal  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 al-
       located for the data structure), malloc_get_state() returns NULL.

       On success, malloc_set_state() returns 0.  If  the  implementation  de-
       tects  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()  re-
       turns -2.

ATTRIBUTES
       For  an  explanation  of  the  terms  used  in  this  section,  see at-
       tributes(7).

       +--------------------+---------------+---------+
       |Interface           | Attribute     | Value   |
       +--------------------+---------------+---------+
       |malloc_get_state(), | Thread safety | MT-Safe |
       |malloc_set_state()  |               |         |
       +--------------------+---------------+---------+

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  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 ALSO
       malloc(3), mallopt(3)

COLOPHON
       This  page  is  part of release 5.05 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
       https://www.kernel.org/doc/man-pages/.

GNU                               2017-09-15               MALLOC_GET_STATE(3)