234 lines
7.5 KiB
HTML
234 lines
7.5 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 -->
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>send</title>
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</head>
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<body bgcolor="white">
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<basefont size="3"> <a name="send"></a> <a name="tag_03_641"></a><!-- send -->
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<!--header start-->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
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IEEE Std 1003.1-2001<br>
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Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<!--header end-->
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<hr size="2" noshade>
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<h4><a name="tag_03_641_01"></a>NAME</h4>
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<blockquote>send - send a message on a socket</blockquote>
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<h4><a name="tag_03_641_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<p><code><tt>#include <<a href="../basedefs/sys/socket.h.html">sys/socket.h</a>><br>
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<br>
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ssize_t send(int</tt> <i>socket</i><tt>, const void *</tt><i>buffer</i><tt>, size_t</tt> <i>length</i><tt>, int</tt>
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<i>flags</i><tt>);<br>
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</tt></code></p>
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</blockquote>
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<h4><a name="tag_03_641_03"></a>DESCRIPTION</h4>
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<blockquote>
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<p>The <i>send</i>() function shall initiate transmission of a message from the specified socket to its peer. The <i>send</i>()
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function shall send a message only when the socket is connected (including when the peer of a connectionless socket has been set
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via <a href="../functions/connect.html"><i>connect</i>()</a>).</p>
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<p>The <i>send</i>() function takes the following arguments:</p>
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<dl compact>
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<dt><i>socket</i></dt>
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<dd>Specifies the socket file descriptor.</dd>
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<dt><i>buffer</i></dt>
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<dd>Points to the buffer containing the message to send.</dd>
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<dt><i>length</i></dt>
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<dd>Specifies the length of the message in bytes.</dd>
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<dt><i>flags</i></dt>
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<dd>Specifies the type of message transmission. Values of this argument are formed by logically OR'ing zero or more of the
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following flags:
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<dl compact>
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<dt>MSG_EOR</dt>
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<dd>Terminates a record (if supported by the protocol).</dd>
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<dt>MSG_OOB</dt>
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<dd>Sends out-of-band data on sockets that support out-of-band communications. The significance and semantics of out-of-band data
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are protocol-specific.</dd>
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</dl>
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</dd>
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</dl>
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<p>The length of the message to be sent is specified by the <i>length</i> argument. If the message is too long to pass through the
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underlying protocol, <i>send</i>() shall fail and no data shall be transmitted.</p>
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<p>Successful completion of a call to <i>send</i>() does not guarantee delivery of the message. A return value of -1 indicates only
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locally-detected errors.</p>
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<p>If space is not available at the sending socket to hold the message to be transmitted, and the socket file descriptor does not
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have O_NONBLOCK set, <i>send</i>() shall block until space is available. If space is not available at the sending socket to hold
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the message to be transmitted, and the socket file descriptor does have O_NONBLOCK set, <i>send</i>() shall fail. The <a href=
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"../functions/select.html"><i>select</i>()</a> and <a href="../functions/poll.html"><i>poll</i>()</a> functions can be used to
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determine when it is possible to send more data.</p>
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<p>The socket in use may require the process to have appropriate privileges to use the <i>send</i>() function.</p>
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</blockquote>
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<h4><a name="tag_03_641_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>Upon successful completion, <i>send</i>() shall return the number of bytes sent. Otherwise, -1 shall be returned and
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<i>errno</i> set to indicate the error.</p>
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</blockquote>
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<h4><a name="tag_03_641_05"></a>ERRORS</h4>
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<blockquote>
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<p>The <i>send</i>() function shall fail if:</p>
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<dl compact>
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<dt>[EAGAIN] or [EWOULDBLOCK]</dt>
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<dd><br>
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The socket's file descriptor is marked O_NONBLOCK and the requested operation would block.</dd>
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<dt>[EBADF]</dt>
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<dd>The <i>socket</i> argument is not a valid file descriptor.</dd>
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<dt>[ECONNRESET]</dt>
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<dd>A connection was forcibly closed by a peer.</dd>
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<dt>[EDESTADDRREQ]</dt>
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<dd><br>
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The socket is not connection-mode and no peer address is set.</dd>
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<dt>[EINTR]</dt>
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<dd>A signal interrupted <i>send</i>() before any data was transmitted.</dd>
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<dt>[EMSGSIZE]</dt>
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<dd>The message is too large to be sent all at once, as the socket requires.</dd>
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<dt>[ENOTCONN]</dt>
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<dd>The socket is not connected or otherwise has not had the peer pre-specified.</dd>
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<dt>[ENOTSOCK]</dt>
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<dd>The <i>socket</i> argument does not refer to a socket.</dd>
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<dt>[EOPNOTSUPP]</dt>
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<dd>The <i>socket</i> argument is associated with a socket that does not support one or more of the values set in
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<i>flags</i>.</dd>
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<dt>[EPIPE]</dt>
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<dd>The socket is shut down for writing, or the socket is connection-mode and is no longer connected. In the latter case, and if
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the socket is of type SOCK_STREAM, the SIGPIPE signal is generated to the calling thread.</dd>
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</dl>
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<p>The <i>send</i>() function may fail if:</p>
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<dl compact>
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<dt>[EACCES]</dt>
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<dd>The calling process does not have the appropriate privileges.</dd>
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<dt>[EIO]</dt>
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<dd>An I/O error occurred while reading from or writing to the file system.</dd>
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<dt>[ENETDOWN]</dt>
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<dd>The local network interface used to reach the destination is down.</dd>
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<dt>[ENETUNREACH]</dt>
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<dd><br>
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No route to the network is present.</dd>
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<dt>[ENOBUFS]</dt>
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<dd>Insufficient resources were available in the system to perform the operation.</dd>
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</dl>
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</blockquote>
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<hr>
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<div class="box"><em>The following sections are informative.</em></div>
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<h4><a name="tag_03_641_06"></a>EXAMPLES</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_641_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>The <i>send</i>() function is equivalent to <a href="../functions/sendto.html"><i>sendto</i>()</a> with a null pointer
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<i>dest_len</i> argument, and to <a href="../functions/write.html"><i>write</i>()</a> if no flags are used.</p>
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</blockquote>
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<h4><a name="tag_03_641_08"></a>RATIONALE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_641_09"></a>FUTURE DIRECTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_641_10"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="connect.html"><i>connect</i>()</a> , <a href="getsockopt.html"><i>getsockopt</i>()</a> , <a href=
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"poll.html"><i>poll</i>()</a> , <a href="recv.html"><i>recv</i>()</a> , <a href="recvfrom.html"><i>recvfrom</i>()</a> , <a href=
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"recvmsg.html"><i>recvmsg</i>()</a> , <a href="select.html"><i>select</i>()</a> , <a href="sendmsg.html"><i>sendmsg</i>()</a> , <a
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href="sendto.html"><i>sendto</i>()</a> , <a href="setsockopt.html"><i>setsockopt</i>()</a> , <a href=
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"shutdown.html"><i>shutdown</i>()</a> , <a href="socket.html"><i>socket</i>()</a> , the Base Definitions volume of
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IEEE Std 1003.1-2001, <a href="../basedefs/sys/socket.h.html"><i><sys/socket.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_641_11"></a>CHANGE HISTORY</h4>
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<blockquote>
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<p>First released in Issue 6. Derived from the XNS, Issue 5.2 specification.</p>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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<hr>
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<center><font size="2"><!--footer start-->
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UNIX ® is a registered Trademark of The Open Group.<br>
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POSIX ® is a registered Trademark of The IEEE.<br>
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[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href=
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"../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>
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