vmlock.c\thread\src - musl - musl - an implementation of the standard library for Linux-based systems

#include "pthread_impl.h"
static volatile int vmlock[2];
void __vm_wait()
{
	int tmp;
	while ((tmp=vmlock[0]))
		__wait(vmlock, vmlock+1, tmp, 1);
}
void __vm_lock()
{
	a_inc(vmlock);
}
void __vm_unlock()
{
	if (a_fetch_add(vmlock, -1)==1 && vmlock[1])
		__wake(vmlock, -1, 1);
}