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       malloc_get_state, malloc_set_state - record and restore state of malloc


       #include <malloc.h>

       void* malloc_get_state(void);

       int malloc_set_state(void *state);


       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.


       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.


       For   an   explanation   of   the  terms  used  in  this  section,  see

       │InterfaceAttributeValue   │
       │malloc_get_state(), │ Thread safety │ MT-Safe │
       │malloc_set_state()  │               │         │


       These functions are GNU extensions.


       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.


       malloc(3), mallopt(3)


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