regress/lib/libpthread/sem2/sem2.c

   1 /*      $NetBSD$        */
   2
   3 /*-
   4  * Copyright (c)2004 YAMAMOTO Takashi,
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <err.h>
  30 #include <errno.h>
  31 #include <pthread.h>
  32 #include <semaphore.h>
  33 #include <signal.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <unistd.h>
  37
  38 sem_t sem;
  39
  40 void sighandler(int);
  41 void *f(void *);
  42 int main(int, char *[]);
  43
  44 void
  45 sighandler(int signo)
  46 {
  47
  48 /*      printf("signal %d\n", signo); */
  49
  50         if (signo != SIGALRM)
  51                 errx(EXIT_FAILURE, "unexpected signal %d", signo);
  52
  53         if (sem_post(&sem))
  54                 err(EXIT_FAILURE, "sem_post");
  55 }
  56
  57 void *
  58 f(void *arg)
  59 {
  60         int i;
  61
  62         for (i = 0; i < 10; ) {
  63                 int ret;
  64
  65                 if ((i & 1) != 0)
  66                         ret = sem_wait(&sem);
  67                 else
  68                         ret = sem_trywait(&sem);
  69                 if (ret) {
  70                         if ((i & 1) !=0 || errno != EAGAIN)
  71                                 err(EXIT_FAILURE, "sem_trywait");
  72                         continue;
  73                 }
  74                 printf("%s: %d\n", __func__, i);
  75                 alarm(1);
  76                 i++;
  77         }
  78
  79         return NULL;
  80 }
  81
  82 int
  83 main(int argc, char *argv[])
  84 {
  85 #if defined(USE_PTHREAD)
  86         int ret;
  87         pthread_t t;
  88 #endif
  89
  90         alarm(1);
  91
  92         if (sem_init(&sem, 0, 0))
  93                 err(EXIT_FAILURE, "sem_init");
  94
  95 #if defined(USE_PTHREAD)
  96         ret = pthread_create(&t, NULL, f, NULL);
  97         if (ret)
  98                 err(EXIT_FAILURE, "pthread_create");
  99 #endif
 100
 101         if (SIG_ERR == signal(SIGALRM, sighandler))
 102                 err(EXIT_FAILURE, "signal");
 103
 104 #if defined(USE_PTHREAD)
 105         ret = pthread_join(t, NULL);
 106         if (ret)
 107                 err(EXIT_FAILURE, "pthread_join");
 108 #else
 109         f(NULL);
 110 #endif
 111
 112         exit(EXIT_SUCCESS);
 113 }