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Annotation of 43BSD/lib/libc/gen/usleep.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1985 Regents of the University of California.
        !             3:  * All rights reserved.  The Berkeley software License Agreement
        !             4:  * specifies the terms and conditions for redistribution.
        !             5:  */
        !             6: 
        !             7: #if defined(LIBC_SCCS) && !defined(lint)
        !             8: static char sccsid[] = "@(#)usleep.c   5.2 (Berkeley) 3/9/86";
        !             9: #endif LIBC_SCCS and not lint
        !            10: 
        !            11: #include <sys/time.h>
        !            12: #include <signal.h>
        !            13: 
        !            14: #define USPS   1000000         /* number of microseconds in a second */
        !            15: #define TICK   10000           /* system clock resolution in microseconds */
        !            16: 
        !            17: #define        setvec(vec, a) \
        !            18:        vec.sv_handler = a; vec.sv_mask = vec.sv_onstack = 0
        !            19: 
        !            20: static int ringring;
        !            21: 
        !            22: usleep(n)
        !            23:        unsigned n;
        !            24: {
        !            25:        int sleepx(), omask;
        !            26:        struct itimerval itv, oitv;
        !            27:        register struct itimerval *itp = &itv;
        !            28:        struct sigvec vec, ovec;
        !            29: 
        !            30:        if (n == 0)
        !            31:                return;
        !            32:        timerclear(&itp->it_interval);
        !            33:        timerclear(&itp->it_value);
        !            34:        if (setitimer(ITIMER_REAL, itp, &oitv) < 0)
        !            35:                return;
        !            36:        itp->it_value.tv_sec = n / USPS;
        !            37:        itp->it_value.tv_usec = n % USPS;
        !            38:        if (timerisset(&oitv.it_value)) {
        !            39:                if (timercmp(&oitv.it_value, &itp->it_value, >)) {
        !            40:                        oitv.it_value.tv_sec -= itp->it_value.tv_sec;
        !            41:                        oitv.it_value.tv_usec -= itp->it_value.tv_usec;
        !            42:                        if (oitv.it_value.tv_usec < 0) {
        !            43:                                oitv.it_value.tv_usec += USPS;
        !            44:                                oitv.it_value.tv_sec--;
        !            45:                        }
        !            46:                } else {
        !            47:                        itp->it_value = oitv.it_value;
        !            48:                        oitv.it_value.tv_sec = 0;
        !            49:                        oitv.it_value.tv_usec = 2 * TICK;
        !            50:                }
        !            51:        }
        !            52:        setvec(vec, sleepx);
        !            53:        (void) sigvec(SIGALRM, &vec, &ovec);
        !            54:        omask = sigblock(sigmask(SIGALRM));
        !            55:        ringring = 0;
        !            56:        (void) setitimer(ITIMER_REAL, itp, (struct itimerval *)0);
        !            57:        while (!ringring)
        !            58:                sigpause(omask &~ sigmask(SIGALRM));
        !            59:        (void) sigvec(SIGALRM, &ovec, (struct sigvec *)0);
        !            60:        (void) sigsetmask(omask);
        !            61:        (void) setitimer(ITIMER_REAL, &oitv, (struct itimerval *)0);
        !            62: }
        !            63: 
        !            64: static
        !            65: sleepx()
        !            66: {
        !            67: 
        !            68:        ringring = 1;
        !            69: }

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