__malloc_lock, __malloc_unlock—lock malloc pool #include <malloc.h>
void __malloc_lock (struct _reent *reent);
void __malloc_unlock (struct _reent *reent);
Description
The malloc family of routines call these functions when they need to lock
the memory pool. The version of these routines supplied in the library use
the lock API defined in sys/lock.h. If multiple threads of execution can
call malloc, or if malloc can be called reentrantly, then you need to
define your own versions of these functions in order to safely lock the
memory pool during a call. If you do not, the memory pool may become
corrupted.
A call to malloc may call __malloc_lock recursively; that is,
the sequence of calls may go __malloc_lock, __malloc_lock,
__malloc_unlock, __malloc_unlock. Any implementation of these
routines must be careful to avoid causing a thread to wait for a lock
that it already holds.