#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include <pthread.h>
#include <linux/futex.h>
#include <sys/time.h>

#include <sys/syscall.h>
#include <sys/types.h>
#include <limits.h>

#include <errno.h>

/* Versão sem time-out */
int futex_wait(void *addr, int val1) {
  int r;
  r = syscall(SYS_futex, addr, FUTEX_WAIT, val1, NULL, NULL, 0);
  if (r == -1) {
    if (errno == EINTR)
      printf("Sinal recebido.\n");
    else if (errno == EWOULDBLOCK)
      printf("Futex_wait não bloqueou.\n");
    else {
      perror("");
      exit(0);
    }
  }
  return r;
}

/* Returns the number of threads which have been queued */
int futex_wake(void *addr, int n) {
  int r;
  if ((r = syscall(SYS_futex, addr, FUTEX_WAKE, n, NULL, NULL, 0)) == -1) {
    perror("");
    exit(0);
  }
  return r;
}