MALLOC_GET_STATE
Section: Linux Programmer's Manual (3)
Updated: 2017-09-15
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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(),
malloc_set_state()
| Thread safety | MT-Safe
|
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 4.13 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ATTRIBUTES
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
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