2 .\" Hey Emacs! This file is -*- nroff -*- source.
4 .\" Copyright (C) 2006 Michael Kerrisk <mtk.manpages@gmail.com>
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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16 .\" manual page may be incorrect or out-of-date.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
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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 2006-04-23, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
28 .\" Updated 2008-11-09, Akihiro MOTOKI, LDP v3.13
30 .TH MQ_RECEIVE 3 2010-09-20 "Linux" "Linux Programmer's Manual"
33 .\"O mq_receive, mq_timedreceive \- receive a message from a message queue
34 mq_receive, mq_timedreceive \- ¥á¥Ã¥»¡¼¥¸¥¥å¡¼¤«¤é¥á¥Ã¥»¡¼¥¸¤ò¼õ¿®¤¹¤ë
38 .B #include <mqueue.h>
40 .BI "ssize_t mq_receive(mqd_t " mqdes ", char *" msg_ptr ,
41 .BI " size_t " msg_len ", unsigned *" msg_prio );
44 .B #include <mqueue.h>
46 .BI "ssize_t mq_timedreceive(mqd_t " mqdes ", char *" msg_ptr ,
47 .BI " size_t " msg_len ", unsigned *" msg_prio ,
48 .BI " const struct timespec *" abs_timeout );
51 .\"O Link with \fI\-lrt\fP.
52 \fI\-lrt\fP ¤Ç¥ê¥ó¥¯¤¹¤ë¡£
56 .\"O Feature Test Macro Requirements for glibc (see
57 .\"O .BR feature_test_macros (7)):
58 glibc ¸þ¤±¤Îµ¡Ç½¸¡ºº¥Þ¥¯¥í¤ÎÍ×·ï
59 .RB ( feature_test_macros (7)
63 .BR mq_timedreceive ():
65 _XOPEN_SOURCE\ >=\ 600 || _POSIX_C_SOURCE\ >=\ 200112L
70 .\"O .BR mq_receive ()
71 .\"O removes the oldest message with the highest priority from
72 .\"O the message queue referred to by the descriptor
74 .\"O and places it in the buffer pointed to by
79 ¤Ç»²¾È¤µ¤ì¤ë¥á¥Ã¥»¡¼¥¸¥¥å¡¼¤«¤éºÇ¤â¹â¤¤Í¥ÀèÅÙ¤ò»ý¤Ä
80 ºÇ¤â¸Å¤¤¥á¥Ã¥»¡¼¥¸¤òºï½ü¤·¡¢¤½¤Î¥á¥Ã¥»¡¼¥¸¤ò
82 ¤¬»Ø¤¹¥Ð¥Ã¥Õ¥¡¤Ë³ÊǼ¤¹¤ë¡£
85 .\"O argument specifies the size of the buffer pointed to by
87 .\"O this must be greater than the
89 .\"O attribute of the queue (see
90 .\"O .BR mq_getattr (3)).
94 ¤¬»Ø¤¹¥Ð¥Ã¥Õ¥¡¤ÎÂ礤µ¤ò¼¨¤¹¡£¤³¤ÎÃͤϥ¥å¡¼¤Î
96 °À¤è¤ê¤âÂ礤¯¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤
101 .\"O is not NULL, then the buffer to which it points is used
102 .\"O to return the priority associated with the received message.
106 ¤¬»Ø¤¹¥Ð¥Ã¥Õ¥¡¤Ë¼õ¿®¤·¤¿¥á¥Ã¥»¡¼¥¸¤ÎÍ¥ÀèÅÙ¤¬³ÊǼ¤µ¤ì¤ë¡£
108 .\"O If the queue is empty, then, by default,
109 .\"O .BR mq_receive ()
110 .\"O blocks until a message becomes available,
111 .\"O or the call is interrupted by a signal handler.
114 .\"O flag is enabled for the message queue description,
115 .\"O then the call instead fails immediately with the error
117 ¥¥å¡¼¤¬¶õ¤Î¾ì¹ç¡¢¥Ç¥Õ¥©¥ë¥È¤Ç¤Ï¡¢
119 ¤Ï¡¢¿·¤·¤¤¥á¥Ã¥»¡¼¥¸¤¬ÆϤ¯¤«¡¢´Ø¿ô¸Æ¤Ó½Ð¤·¤¬¥·¥°¥Ê¥ë¥Ï¥ó¥É¥é¤Ë¤è¤ê
120 ÃæÃǤµ¤ì¤ë¤Þ¤Ç¡¢Ää»ß (block) ¤¹¤ë¡£
121 ¥á¥Ã¥»¡¼¥¸¥¥å¡¼µ½Ò (message queue description) ¤Ç
123 ¥Õ¥é¥°¤¬Í¸ú¤Ë¤Ê¤Ã¤Æ¤¤¤ë¾ì¹ç¤Ï¡¢
129 .\"O .BR mq_timedreceive ()
130 .\"O behaves just like
131 .\"O .BR mq_receive (),
132 .\"O except that if the queue is empty and the
134 .\"O flag is not enabled for the message queue description, then
136 .\"O points to a structure which specifies a ceiling on the time for which
137 .\"O the call will block.
138 .\"O This ceiling is an absolute timeout in seconds and nanoseconds
139 .\"O since the Epoch, 1970-01-01 00:00:00 +0000 (UTC), and it is
140 .\"O specified in the following structure:
141 .BR mq_timedreceive ()
144 ¤ÈÁ´¤¯Æ±¤¸Æ°ºî¤ò¤¹¤ë¤¬¡¢
145 ¥á¥Ã¥»¡¼¥¸¥¥å¡¼¤¬¶õ¤Ç¡¢¥á¥Ã¥»¡¼¥¸¥¥å¡¼µ½Ò¤Ç
147 ¥Õ¥é¥°¤¬Í¸ú¤Ë¤Ê¤Ã¤Æ¤¤¤Ê¤¤¾ì¹ç¤Ë¡¢¤³¤Î¸Æ¤Ó½Ð¤·¤¬Ää»ß¤¹¤ë»þ´Ö¤Î¾å¸Â¤ò
149 ¤¬»Ø¤¹¹½Â¤ÂΤǻØÄꤹ¤ëÅÀ¤¬°Û¤Ê¤ë¡£¤³¤Î¾å¸Â¤Ï¡¢¥¿¥¤¥à¥¢¥¦¥È¤Î»þ¹ï¤ò¡¢
150 »þ¹ïµª¸µ (Epoch; 1970-01-01 00:00:00 +0000 (UTC)) ¤«¤é¤Î·Ð²á»þ´Ö
151 (ÉäȥʥÎÉäÎÁÈ) ¤Ç»ØÄꤹ¤ë¡£¥¿¥¤¥à¥¢¥¦¥È»þ¹ï¤Ï°Ê²¼¤Î¹½Â¤ÂΤǻØÄꤹ¤ë:
156 .\"O time_t tv_sec; /* seconds */
157 .\"O long tv_nsec; /* nanoseconds */
158 time_t tv_sec; /* ÉÃ */
159 long tv_nsec; /* ¥Ê¥ÎÉà */
164 .\"O If no message is available,
165 .\"O and the timeout has already expired by the time of the call,
166 .\"O .BR mq_timedreceive ()
167 .\"O returns immediately.
168 ¥á¥Ã¥»¡¼¥¸¤¬¥¥å¡¼¤Ë¤Ê¤¯¡¢´Ø¿ô¸Æ¤Ó½Ð¤·»þ¤Ë¤¹¤Ç¤Ë¥¿¥¤¥à¥¢¥¦¥È»þ¹ï¤¬
170 .BR mq_timedreceive ()
172 .\"O .SH RETURN VALUE
175 .\"O .BR mq_receive ()
177 .\"O .BR mq_timedreceive ()
178 .\"O return the number of bytes in the received message;
179 .\"O on error, \-1 is returned, with
181 .\"O set to indicate the error.
185 .BR mq_timedreceive ()
186 ¤Ï¼õ¿®¤·¤¿¥á¥Ã¥»¡¼¥¸¤Î¥Ð¥¤¥È¿ô¤òÊÖ¤¹¡£
187 ¥¨¥é¡¼¤Î¾ì¹ç¡¢\-1 ¤òÊÖ¤·¡¢
189 ¤Ë¥¨¥é¡¼¤ò¼¨¤¹ÃͤòÀßÄꤹ¤ë¡£
194 .\"O The queue was empty, and the
196 .\"O flag was set for the message queue description referred to by
200 ¤Ç»²¾È¤µ¤ì¤ë¥á¥Ã¥»¡¼¥¸¥¥å¡¼µ½Ò¤Ç
202 ¥Õ¥é¥°¤¬¥»¥Ã¥È¤µ¤ì¤Æ¤¤¤¿¡£
205 .\"O The descriptor specified in
209 ¤Ç»ØÄꤵ¤ì¤¿µ½Ò»Ò¤¬ÉÔÀµ¤Ç¤¢¤ë¡£
212 .\"O The call was interrupted by a signal handler; see
214 ´Ø¿ô¸Æ¤Ó½Ð¤·¤¬¥·¥°¥Ê¥ë¥Ï¥ó¥É¥é¤Ë¤è¤êÃæÃǤµ¤ì¤¿¡£
219 .\"O The call would have blocked, and
221 .\"O was invalid, either because
223 .\"O was less than zero, or because
225 .\"O was less than zero or greater than 1000 million.
226 ´Ø¿ô¸Æ¤Ó½Ð¤·¤ÏÄä»ß¤¹¤ë¤Ï¤º¤Ç¤¢¤Ã¤¿¤¬¡¢
234 ¤¬ 0 ̤Ëþ¤« 1,000,000,000 ¤è¤êÂ礤¤¡¢¤È¤¤¤¦¤³¤È¤Ç¤¢¤ë¡£
238 .\"O was less than the
240 .\"O attribute of the message queue.
244 °À¤è¤ê¤â¾®¤µ¤«¤Ã¤¿¡£
247 .\"O The call timed out before a message could be transferred.
248 ¥á¥Ã¥»¡¼¥¸¤¬Å¾Á÷¤µ¤ì¤ëÁ°¤Ë´Ø¿ô¸Æ¤Ó½Ð¤·¤¬¥¿¥¤¥à¥¢¥¦¥È¤·¤¿¡£
249 .\"O .SH CONFORMING TO
255 .\"O .BR mq_timedreceive ()
256 .\"O is a system call, and
257 .\"O .BR mq_receive ()
258 .\"O is a library function layered on top of that system call.
260 .BR mq_timedreceive ()
261 ¤Ï¥·¥¹¥Æ¥à¥³¡¼¥ë¤Ç¤¢¤ë¡£
264 .BR mq_timedreceive ()
265 ¥·¥¹¥Æ¥à¥³¡¼¥ë¤òÍѤ¤¤Æ¼ÂÁõ¤µ¤ì¤Æ¤¤¤ë¡£