2 .\" Hey Emacs! This file is -*- nroff -*- source.
4 .\" Copyright (C) 2006 Michael Kerrisk <mtk.manpages@gmail.com>
6 .\" Permission is granted to make and distribute verbatim copies of this
7 .\" manual provided the copyright notice and this permission notice are
8 .\" preserved on all copies.
10 .\" Permission is granted to copy and distribute modified versions of this
11 .\" manual under the conditions for verbatim copying, provided that the
12 .\" entire resulting derived work is distributed under the terms of a
13 .\" permission notice identical to this one.
15 .\" Since the Linux kernel and libraries are constantly changing, this
16 .\" manual page may be incorrect or out-of-date. The author(s) assume no
17 .\" responsibility for errors or omissions, or for damages resulting from
18 .\" the use of the information contained herein. The author(s) may not
19 .\" have taken the same level of care in the production of this manual,
20 .\" which is licensed free of charge, as they might when working
23 .\" Formatted or processed versions of this manual, if unaccompanied by
24 .\" the source, must acknowledge the copyright and authors of this work.
26 .\" Japanese Version Copyright (c) 2006 Akihiro MOTOKI all rights reserved.
27 .\" Translated 2006-04-18, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
29 .TH SEM_WAIT 3 2010-02-25 "Linux" "Linux Programmer's Manual"
31 sem_wait, sem_timedwait, sem_trywait \- ¥»¥Þ¥Õ¥©¤ò¥í¥Ã¥¯¤¹¤ë
34 .B #include <semaphore.h>
36 .BI "int sem_wait(sem_t *" sem );
38 .BI "int sem_trywait(sem_t *" sem );
40 .BI "int sem_timedwait(sem_t *" sem ", const struct timespec *" abs_timeout );
44 \fI\-lrt\fP ¤Þ¤¿¤Ï \fI\-pthread\fP ¤Ç¥ê¥ó¥¯¤¹¤ë¡£
46 glibc ¸þ¤±¤Îµ¡Ç½¸¡ºº¥Þ¥¯¥í¤ÎÍ×·ï
47 .RB ( feature_test_macros (7)
52 _POSIX_C_SOURCE\ >=\ 200112L || _XOPEN_SOURCE\ >=\ 600
57 ¤¬»Ø¤¹¥»¥Þ¥Õ¥©¤ÎÃͤò 1 ¸º¤é¤¹ (¥í¥Ã¥¯¤¹¤ë)¡£
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82 °ú¤¿ô¤Ï¡¢¥¿¥¤¥à¥¢¥¦¥È»þ¹ï¤ò»ØÄꤹ¤ë¹½Â¤ÂΤؤΥݥ¤¥ó¥¿¤Ç¤¢¤ë¡£
83 ¤³¤Î¹½Â¤ÂΤˤϡ¢¥¿¥¤¥à¥¢¥¦¥È»þ¹ï¤ò»þ¹ïµª¸µ (Epoch;
84 1970-01-01 00:00:00 +0000 (UTC)) ¤«¤é¤Î
85 ·Ð²á»þ´Ö (ÉáܥʥÎÉÃ) ¤Ç»ØÄꤹ¤ë¡£
86 ¹½Â¤ÂΤϰʲ¼¤Î¤è¤¦¤ËÄêµÁ¤µ¤ì¤Æ¤¤¤ë:
91 time_t tv_sec; /* Seconds */
92 long tv_nsec; /* Nanoseconds [0 .. 999999999] */
97 ´Ø¿ô¸Æ¤Ó½Ð¤·»þÅÀ¤Ç¤¹¤Ç¤Ë¥¿¥¤¥à¥¢¥¦¥È¤Ë»ØÄꤷ¤¿»þ¹ï¤¬²á¤®¤Æ¤ª¤ê¡¢
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115 ¥¨¥é¡¼¤Î¾ì¹ç¡¢¥»¥Þ¥Õ¥©¤ÎÃͤòÊѹ¹¤»¤º¤Ë¡¢\-1 ¤òÊÖ¤·¡¢
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137 ¤Î¾ì¹ç¡¢°Ê²¼¤Î¥¨¥é¡¼¤âµ¯¤³¤ë¡£
140 .I abs_timeout.tv_nsecs
141 ¤ÎÃͤ¬ 0 ̤Ëþ¡¢¤â¤·¤¯¤Ï 1,000,000,000 °Ê¾å¤Ç¤¢¤ë¡£
144 ¥»¥Þ¥Õ¥©¤Î¥í¥Ã¥¯¤ËÀ®¸ù¤¹¤ëÁ°¤Ë»þ´ÖÀÚ¤ì¤È¤Ê¤Ã¤¿¡£
145 .\" POSIX.1-2001 ¤Ç¤Ï¥¨¥é¡¼¤È¤·¤Æ EDEADLK ¤âÍÑ°Õ¤·¤Æ¤¤¤ë¡£
146 .\" ¤³¤ì¤Ï¥Ç¥Ã¥É¥í¥Ã¥¯¾ò·ï¤ò¸¡½Ð¤·¤¿¤³¤È¤ò¼¨¤¹¤â¤Î¤À¤¬¡¢
147 .\" Linux ¤ÇȯÀ¸¤¹¤ë¤³¤È¤Ï¤Ê¤¤(?)
154 ¥Õ¥é¥°¤ò»ÈÍѤ·¤Æ¤¤¤ë¤«¤É¤¦¤«¤Ë´Ø¤ï¤é¤º¡¢¤³¤ì¤é¤Î´Ø¿ô¤Î¸Æ¤Ó½Ð¤·¤¬
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156 .\" sem_wait() ¤Ï¾¤Î¤Û¤È¤ó¤É¤Î¼ÂÁõ¤Ç¤Ï¾ï¤ËÃæÃǤµ¤ì¤ë¤¬¡¢
157 .\" FreeBSD 5.4 ¤Ç¤Ï SA_RESTART ¤ò»ØÄꤷ¤Æ¤ª¤¯¤È¼Â¹Ô¤¬ºÆ³«¤µ¤ì¤ë¡£
160 °Ê²¼¤Ë¼¨¤¹ (¤Á¤ç¤Ã¤È¤·¤¿) ¥×¥í¥°¥é¥à¤Ï̾Á°¤Ê¤·¥»¥Þ¥Õ¥©¤ÎÁàºî¤ò¹Ô¤¦¡£
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174 ¤ËÅϤ¹¥¿¥¤¥à¥¢¥¦¥È¤Þ¤Ç¤Î»þ´Ö¤òÉÃñ°Ì¤Ç»ØÄꤹ¤ë¡£
178 .RB "$" " ./a.out 2 3"
179 About to call sem_timedwait()
180 sem_post() from handler
181 sem_getvalue() from handler; value = 1
182 sem_timedwait() succeeded
183 .RB "$" " ./a.out 2 1"
184 About to call sem_timedwait()
185 sem_timedwait() timed out
188 .SS ¥×¥í¥°¥é¥à¤Î¥½¡¼¥¹
194 #include <semaphore.h>
202 #define handle_error(msg) \\
203 do { perror(msg); exit(EXIT_FAILURE); } while (0)
208 write(STDOUT_FILENO, "sem_post() from handler\\n", 24);
209 if (sem_post(&sem) == \-1) {
210 write(STDERR_FILENO, "sem_post() failed\\n", 18);
216 main(int argc, char *argv[])
223 fprintf(stderr, "Usage: %s <alarm\-secs> <wait\-secs>\\n",
228 if (sem_init(&sem, 0, 0) == \-1)
229 handle_error("sem_init");
231 /* Establish SIGALRM handler; set alarm timer using argv[1] */
233 sa.sa_handler = handler;
234 sigemptyset(&sa.sa_mask);
236 if (sigaction(SIGALRM, &sa, NULL) == \-1)
237 handle_error("sigaction");
239 alarm(atoi(argv[1]));
241 /* Calculate relative interval as current time plus
242 number of seconds given argv[2] */
244 if (clock_gettime(CLOCK_REALTIME, &ts) == \-1)
245 handle_error("clock_gettime");
247 ts.tv_sec += atoi(argv[2]);
249 printf("main() about to call sem_timedwait()\\n");
250 while ((s = sem_timedwait(&sem, &ts)) == \-1 && errno == EINTR)
251 continue; /* Restart if interrupted by handler */
253 /* Check what happened */
256 if (errno == ETIMEDOUT)
257 printf("sem_timedwait() timed out\\n");
259 perror("sem_timedwait");
261 printf("sem_timedwait() succeeded\\n");
263 exit((s == 0) ? EXIT_SUCCESS : EXIT_FAILURE);
267 .BR clock_gettime (2),
268 .BR sem_getvalue (3),
270 .BR sem_overview (7),