MALLOC_GET_STATE(3) Linux Programmer's Manual MALLOC_GET_STATE(3)
malloc_get_state, malloc_set_state - record and restore state of malloc implementation
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.
These functions are GNU extensions.
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.
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