newlib-cygwin/newlib/libc/stdlib/mlock.c

65 lines
1.6 KiB
C

#ifndef MALLOC_PROVIDED
/*
FUNCTION
<<__malloc_lock>>, <<__malloc_unlock>>---lock malloc pool
INDEX
__malloc_lock
INDEX
__malloc_unlock
ANSI_SYNOPSIS
#include <malloc.h>
void __malloc_lock (struct _reent *<[reent]>);
void __malloc_unlock (struct _reent *<[reent]>);
TRAD_SYNOPSIS
void __malloc_lock(<[reent]>)
struct _reent *<[reent]>;
void __malloc_unlock(<[reent]>)
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.
*/
#include <malloc.h>
#include <sys/lock.h>
#ifndef __SINGLE_THREAD__
__LOCK_INIT_RECURSIVE(static, __malloc_recursive_mutex);
#endif
void
__malloc_lock (ptr)
struct _reent *ptr;
{
#ifndef __SINGLE_THREAD__
__lock_acquire_recursive (__malloc_recursive_mutex);
#endif
}
void
__malloc_unlock (ptr)
struct _reent *ptr;
{
#ifndef __SINGLE_THREAD__
__lock_release_recursive (__malloc_recursive_mutex);
#endif
}
#endif