114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
/* $NetBSD: sem2.c,v 1.1 2004/11/03 15:18:35 yamt Exp $ */
|
|
|
|
/*-
|
|
* Copyright (c)2004 YAMAMOTO Takashi,
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <err.h>
|
|
#include <errno.h>
|
|
#include <pthread.h>
|
|
#include <semaphore.h>
|
|
#include <signal.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
|
|
sem_t sem;
|
|
|
|
void sighandler(int);
|
|
void *f(void *);
|
|
int main(int, char *[]);
|
|
|
|
void
|
|
sighandler(int signo)
|
|
{
|
|
|
|
/* printf("signal %d\n", signo); */
|
|
|
|
if (signo != SIGALRM)
|
|
errx(EXIT_FAILURE, "unexpected signal %d", signo);
|
|
|
|
if (sem_post(&sem))
|
|
err(EXIT_FAILURE, "sem_post");
|
|
}
|
|
|
|
void *
|
|
f(void *arg)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 10; ) {
|
|
int ret;
|
|
|
|
if ((i & 1) != 0)
|
|
ret = sem_wait(&sem);
|
|
else
|
|
ret = sem_trywait(&sem);
|
|
if (ret) {
|
|
if ((i & 1) !=0 || errno != EAGAIN)
|
|
err(EXIT_FAILURE, "sem_trywait");
|
|
continue;
|
|
}
|
|
printf("%s: %d\n", __func__, i);
|
|
alarm(1);
|
|
i++;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
int
|
|
main(int argc, char *argv[])
|
|
{
|
|
#if defined(USE_PTHREAD)
|
|
int ret;
|
|
pthread_t t;
|
|
#endif
|
|
|
|
alarm(1);
|
|
|
|
if (sem_init(&sem, 0, 0))
|
|
err(EXIT_FAILURE, "sem_init");
|
|
|
|
#if defined(USE_PTHREAD)
|
|
ret = pthread_create(&t, NULL, f, NULL);
|
|
if (ret)
|
|
err(EXIT_FAILURE, "pthread_create");
|
|
#endif
|
|
|
|
if (SIG_ERR == signal(SIGALRM, sighandler))
|
|
err(EXIT_FAILURE, "signal");
|
|
|
|
#if defined(USE_PTHREAD)
|
|
ret = pthread_join(t, NULL);
|
|
if (ret)
|
|
err(EXIT_FAILURE, "pthread_join");
|
|
#else
|
|
f(NULL);
|
|
#endif
|
|
|
|
exit(EXIT_SUCCESS);
|
|
}
|