BSD 4_1c_2 release

[unix-history] / usr / src / lib / libc / gen / sleep.c

/* @(#)sleep.c  4.1 (Berkeley) 12/21/80 */
#include <signal.h>
#include <setjmp.h>

static jmp_buf jmp;

sleep(n)
unsigned n;
{
       int sleepx();
       unsigned altime;
       int (*alsig)() = SIG_DFL;

       if (n==0)
               return;
       altime = alarm(1000);   /* time to maneuver */
       if (setjmp(jmp)) {
               signal(SIGALRM, alsig);
               alarm(altime);
               return;
       }
       if (altime) {
               if (altime > n)
                       altime -= n;
               else {
                       n = altime;
                       altime = 1;
               }
       }
       alsig = signal(SIGALRM, sleepx);
       alarm(n);
       for(;;)
               pause();
       /*NOTREACHED*/
}

static
sleepx()
{
       longjmp(jmp, 1);
}