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
       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.

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(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 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 5.09 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)