source: azure_iot_hub/trunk/musl-1.1.18/src/thread/__timedwait.c@ 388

#include <pthread.h>
#include <time.h>
#include <errno.h>
#include "futex.h"
#include "syscall.h"
#include "pthread_impl.h"

int __pthread_setcancelstate(int, int *);
int __clock_gettime(clockid_t, struct timespec *);

int __timedwait_cp(volatile int *addr, int val,
        clockid_t clk, const struct timespec *at, int priv)
{
        int r;
        struct timespec to, *top=0;

        if (priv) priv = FUTEX_PRIVATE;

        if (at) {
                if (at->tv_nsec >= 1000000000UL) return EINVAL;
                if (__clock_gettime(clk, &to)) return EINVAL;
                to.tv_sec = at->tv_sec - to.tv_sec;
                if ((to.tv_nsec = at->tv_nsec - to.tv_nsec) < 0) {
                        to.tv_sec--;
                        to.tv_nsec += 1000000000;
                }
                if (to.tv_sec < 0) return ETIMEDOUT;
                top = &to;
        }

        r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT|priv, val, top);
        if (r == ENOSYS) r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT, val, top);
        if (r != EINTR && r != ETIMEDOUT && r != ECANCELED) r = 0;

        return r;
}

int __timedwait(volatile int *addr, int val,
        clockid_t clk, const struct timespec *at, int priv)
{
        int cs, r;
        __pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
        r = __timedwait_cp(addr, val, clk, at, priv);
        __pthread_setcancelstate(cs, 0);
        return r;
}