sleep2.c

unix高级编程源代码.<<unix高级编程>>

#include	<setjmp.h>
#include	<signal.h>
#include	<unistd.h>

static jmp_buf	env_alrm;

static void
sig_alrm(int signo)
{
	longjmp(env_alrm, 1);
}

unsigned int
sleep2(unsigned int nsecs)
{
	if (signal(SIGALRM, sig_alrm) == SIG_ERR)
		return(nsecs);
	if (setjmp(env_alrm) == 0) {
		alarm(nsecs);		/* start the timer */
		pause();			/* next caught signal wakes us up */
	}
	return( alarm(0) );		/* turn off timer, return unslept time */
}