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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] 12 .TH MQ_SEND 3C "Feb 5, 2008" 13 .SH NAME 14 mq_send, mq_timedsend, mq_reltimedsend_np \- send a message to a message queue 15 .SH SYNOPSIS 16 .LP 17 .nf 18 #include <mqueue.h> 19 20 \fBint\fR \fBmq_send\fR(\fBmqd_t\fR \fImqdes\fR, \fBconst char *\fR\fImsg_ptr\fR, \fBsize_t\fR \fImsg_len\fR, 21 \fBunsigned\fR \fImsg_prio\fR); 22 .fi 23 24 .LP 25 .nf 26 #include <mqueue.h> 27 #include <time.h> 28 29 \fBint\fR \fBmq_timedsend\fR(\fBmqd_t\fR \fImqdes\fR, \fBconst char *\fR\fImsg_ptr\fR, 30 \fBsize_t\fR \fImsg_len\fR, \fBunsigned\fR \fImsg_prio\fR, 31 \fBconst struct timespec *restrict\fR \fIabs_timeout\fR); 32 .fi 33 34 .LP 35 .nf 36 \fBint\fR \fBmq_reltimedsend_np\fR(\fBmqd_t\fR \fImqdes\fR, \fBconst char *\fR\fImsg_ptr\fR, 37 \fBsize_t\fR \fImsg_len\fR, \fBunsigned\fR \fImsg_prio\fR, 38 \fBconst struct timespec *restrict\fR \fIrel_timeout\fR); 39 .fi 40 41 .SH DESCRIPTION 42 .sp 43 .LP 44 The \fBmq_send()\fR function adds the message pointed to by the argument 45 \fImsg_ptr\fR to the message queue specified by \fImqdes\fR. The \fImsg_len\fR 46 argument specifies the length of the message in bytes pointed to by 47 \fImsg_ptr\fR. The value of \fImsg_len\fR is less than or equal to the 48 \fImq_msgsize\fR attribute of the message queue, or \fBmq_send()\fR fails. 49 .sp 50 .LP 51 If the specified message queue is not full, \fBmq_send()\fR behaves as if the 52 message is inserted into the message queue at the position indicated by the 53 \fImsg_prio\fR argument. A message with a larger numeric value of 54 \fImsg_prio\fR is inserted before messages with lower values of \fImsg_prio\fR. 55 A message will be inserted after other messages in the queue, if any, with 56 equal \fImsg_prio\fR. The value of \fImsg_prio\fR must be greater than zero and 57 less than or equal to \fBMQ_PRIO_MAX\fR. 58 .sp 59 .LP 60 If the specified message queue is full and \fBO_NONBLOCK\fR is not set in the 61 message queue description associated with \fImqdes\fR (see \fBmq_open\fR(3C) 62 and \fBmq_setattr\fR(3C)), \fBmq_send()\fR blocks until space becomes available 63 to enqueue the message, or until \fBmq_send()\fR is interrupted by a signal. If 64 more than one thread is waiting to send when space becomes available in the 65 message queue, then the thread of the highest priority which has been waiting 66 the longest is unblocked to send its message. Otherwise, it is unspecified 67 which waiting thread is unblocked. If the specified message queue is full and 68 \fBO_NONBLOCK\fR is set in the message queue description associated with 69 \fImqdes\fR, the message is not queued and \fBmq_send()\fR returns an error. 70 .sp 71 .LP 72 The \fBmq_timedsend()\fR function adds a message to the message queue specified 73 by \fImqdes\fR in the manner defined for the \fBmq_send()\fR function. However, 74 if the specified message queue is full and \fBO_NONBLOCK\fR is not set in the 75 message queue description associated with \fImqdes\fR, the wait for sufficient 76 room in the queue is terminated when the specified timeout expires. If 77 \fBO_NONBLOCK\fR is set in the message queue description, this function is 78 equivalent to \fBmq_send()\fR. 79 .sp 80 .LP 81 The \fBmq_reltimedsend_np()\fR function is identical to the 82 \fBmq_timedsend()\fR function, except that the timeout is specified as a 83 relative time interval. 84 .sp 85 .LP 86 For \fBmq_timedsend()\fR, the timeout expires when the absolute time specified 87 by \fIabs_timeout\fR passes, as measured by the \fBCLOCK_REALTIME\fR clock 88 (that is, when the value of that clock equals or exceeds \fIabs_timeout\fR), or 89 if the absolute time specified by \fIabs_timeout\fR has already been passed at 90 the time of the call. 91 .sp 92 .LP 93 For \fBmq_reltimedsend_np()\fR, the timeout expires when the time interval 94 specified by \fIrel_timeout\fR passes, as measured by the \fBCLOCK_REALTIME\fR 95 clock, or if the time interval specified by \fIrel_timeout\fR is negative at 96 the time of the call. 97 .sp 98 .LP 99 The resolution of the timeout is the resolution of the \fBCLOCK_REALTIME\fR 100 clock. The \fBtimespec\fR argument is defined in the <\fBtime.h\fR> header. 101 .sp 102 .LP 103 Under no circumstance does the operation fail with a timeout if there is 104 sufficient room in the queue to add the message immediately. The validity of 105 the timeout parameter need not be checked when there is sufficient room in the 106 queue. 107 .SH RETURN VALUES 108 .sp 109 .LP 110 Upon successful completion, \fBmq_send()\fR, \fBmq_timedsend()\fR, and 111 \fBmq_reltimedsend_np()\fR return \fB0\fR. Otherwise, no message is enqueued, 112 the functions return \fB\(mi1\fR, and \fBerrno\fR is set to indicate the error. 113 .SH ERRORS 114 .sp 115 .LP 116 The \fBmq_send()\fR, \fBmq_timedsend()\fR, and \fBmq_reltimedsend_np()\fR 117 functions will fail if: 118 .sp 119 .ne 2 120 .na 121 \fB\fBEAGAIN\fR \fR 122 .ad 123 .RS 13n 124 The \fBO_NONBLOCK\fR flag is set in the message queue description associated 125 with \fImqdes\fR, and the specified message queue is full. 126 .RE 127 128 .sp 129 .ne 2 130 .na 131 \fB\fBEBADF\fR \fR 132 .ad 133 .RS 13n 134 The \fImqdes\fR argument is not a valid message queue descriptor open for 135 writing. 136 .RE 137 138 .sp 139 .ne 2 140 .na 141 \fB\fBEINTR\fR \fR 142 .ad 143 .RS 13n 144 A signal interrupted the function call. 145 .RE 146 147 .sp 148 .ne 2 149 .na 150 \fB\fBEINVAL\fR\fR 151 .ad 152 .RS 13n 153 The value of \fImsg_prio\fR was outside the valid range. 154 .RE 155 156 .sp 157 .ne 2 158 .na 159 \fB\fBEINVAL\fR\fR 160 .ad 161 .RS 13n 162 The process or thread would have blocked, and the timeout parameter specified a 163 nanoseconds field value less than zero or greater than or equal to 1,000 164 million. 165 .RE 166 167 .sp 168 .ne 2 169 .na 170 \fB\fBEMSGSIZE\fR \fR 171 .ad 172 .RS 13n 173 The specified message length, \fImsg_len\fR, exceeds the message size attribute 174 of the message queue. 175 .RE 176 177 .sp 178 .ne 2 179 .na 180 \fB\fBETIMEDOUT\fR\fR 181 .ad 182 .RS 13n 183 The \fBO_NONBLOCK\fR flag was not set when the message queue was opened, but 184 the timeout expired before the message could be added to the queue. 185 .RE 186 187 .SH ATTRIBUTES 188 .sp 189 .LP 190 See \fBattributes\fR(5) for descriptions of the following attributes: 191 .sp 192 193 .sp 194 .TS 195 box; 196 l | l 197 l | l . 198 ATTRIBUTE TYPE ATTRIBUTE VALUE 199 _ 200 Interface Stability Committed 201 _ 202 MT-Level MT-Safe 203 _ 204 Standard See below. 205 .TE 206 207 .sp 208 .LP 209 For \fBmq_send()\fR and \fBmq_timedsend()\fR, see \fBstandards\fR(5). 210 .SH SEE ALSO 211 .sp 212 .LP 213 \fBsysconf\fR(3C), \fBmqueue.h\fR(3HEAD), \fBmq_open\fR(3C), 214 \fBmq_receive\fR(3C), \fBmq_setattr\fR(3C), \fBattributes\fR(5), 215 \fBstandards\fR(5)