📄 send.htm
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<html><head><meta http-equiv="Content-Language" content="en-us"><meta http-equiv="Content-Type" content="text/html; charset=windows-1252"><title>UDT Reference</title></head><body><table border="1" cellpadding="0" cellspacing="0" style="border-collapse: collapse" width="100%" id="table2" bgcolor="#99CCFF" bordercolor="#99CCFF"> <tr> <td width="100%"><font face="Verdana" size="2"><i> UDT Reference: UDT Functions</i></font></td> </tr></table><h1 style="margin-bottom: 0"><font face="Verdana" size="4">send</font></h1><p><font face="Verdana" size="2">The <b>send </b>method sends out an application buffer.</font></p><table border="1" cellpadding="0" cellspacing="0" style="border-collapse: collapse" width="100%" id="table3" bgcolor="#C0C0C0" bordercolor="#C0C0C0"> <tr> <td width="100%"> <p style="margin-top: 0; margin-bottom: 0"> <font size="1" face="Courier New">int send(<br> UDTSOCKET <font color="#FFFFFF">u</font>, <br> const char *<font color="#FFFFFF"><a class="synParam" onclick="showTip(this)">buf</a></font>, <br> int <font color="#FFFFFF"> <a class="synParam" onclick="showTip(this)">len</a></font>, <br> int <a class="synParam" onclick="showTip(this)"><font color="#FFFFFF">flags</font>,</a></font></p> <p style="margin-top: 0; margin-bottom: 0"> <font face="Courier New" size="1"> int *<font color="#FFFFFF">handle </font> = NULL,</font></p> <p style="margin-top: 0; margin-bottom: 0"> <font face="Courier New" size="1"> <a href="structure.htm#MEM">UDT_MEM_ROUTINE</a> <font color="#FFFFFF">routine</font> = NULL</font></p> <p style="margin-top: 0; margin-bottom: 0"> <font face="Courier New" size="1"> void* <font color="#FFFFFF">context</font> = NULL <br> );</font></p> </td> </tr></table><h4><font face="Verdana" size="2">Parameters</font></h4><dl> <dt><font face="Verdana"><i><font size="2">u</font></i><font size="2"> </font></font> </dt> <dd><font face="Verdana" size="2">[in] Descriptor identifying a connected socket. </font></dd> <dt><font face="Verdana"><i><font size="2">buf</font></i><font size="2"> </font></font> </dt> <dd><font face="Verdana" size="2">[in] Buffer containing the data to be transmitted. </font></dd> <dt><font face="Verdana"><i><font size="2">len</font></i><font size="2"> </font></font> </dt> <dd><font face="Verdana" size="2">[in] Length of the data in <i>buf</i>. </font> </dd> <dt><font face="Verdana"><i><font size="2">flags</font></i><font size="2"> </font></font> </dt> <dd><font face="Verdana" size="2">[in] Ignored. For compatibility use only. </font></dd> <dt><font face="Verdana"><i><font size="2">handle</font></i><font size="2"> </font></font> </dt> <dd><font face="Verdana" size="2">[out] Optional. An descriptor to this send call. </font></dd> <dt><font face="Verdana"><i><font size="2">routine</font></i><font size="2"> </font></font> </dt> <dd><font face="Verdana" size="2">[in] optional. Function used to process the buffer after the sending is finished. </font></dd> <dt><font size="2" face="Verdana"><i>context</i></font> </dt> <dd><font face="Verdana" size="2">[in] optional. Context parameter to be used in the buffer process routine. </font></dd></dl><h4><font face="Verdana" size="2">Return Values</font></h4><p><font face="Verdana" size="2">On success, the actual size of data sent is returned; Otherwise,UDT::ERROR is returned and the specific error information can be retrieved by<a href="error.htm">getlasterror</a>. When UDT_SNDTIMEO is set to a positivevalue, zero will be returned if no data is sent out before the assigned timerexpires.</font></p> <table border="1" cellpadding="0" cellspacing="0" style="border-collapse: collapse" id="table4" bordercolordark="#C0C0C0" bordercolorlight="#C0C0C0" width="100%"> <tr> <th align="center" bgcolor="#C0C0C0" width="133"> <font face="Verdana" size="2">Error Code</font></th> <th align="center" bgcolor="#C0C0C0" width="812"><b> <font face="Verdana" size="2">Comment</font></b></th> </tr> <tr> <td width="133"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> 2001</font></td> <td width="812"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> connection broken before send is completed.</font></td> </tr> <tr> <td width="133"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> 2002</font></td> <td width="812"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> <i>u </i>is not connected.</font></td> </tr> <tr> <td width="133"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> 5003</font></td> <td width="812"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> invalid parameters.</font></td> </tr> <tr> <td width="133"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> 5004</font></td> <td width="812"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> <i>u</i> is an invalid UDT socket.</font></td> </tr> <tr> <td width="133"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> 5010</font></td> <td width="812"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> cannot use <i>send</i> in SOCK_DGRAM mode.</font></td> </tr> <tr> <td width="133"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> 6001</font></td> <td width="812"> <p style="margin-top: 1; margin-bottom: 1"><font face="Verdana" size="1"> insufficient buffer size for non-blocking sending.</font></td> </tr> </table><H4><font face="Verdana" size="2">Description</font></H4><P><font face="Verdana" size="2">The <b>send </b>method's behavior depends on the sending blocking mode and overlapped IO.</font></P><P><font face="Verdana" size="2">In regular IO, with blocking mode, the send is blocked until there is enough buffer size in the UDT sender's buffer. On non-blocking IO, send will return immediately. UDT <b>send</b> either sends all the data specified by the length parameter or nothing. However, it is still recommended to use a loop to check the return value for future compatibilities.</font></P><P><font face="Verdana" size="2">In overlapped IO (when the <i>handle</i> parameter is given), a blocking sending waits until all data are sent out, whereas a non-blocking sending returns immediately and the data will be sent at background (if there is enough buffer). Once the data sending is completed, the function of <i>routine</i> will be executed on the data. Note that UDT does not duplicate the <i>context</i>parameter: it should remain valid until the <i>routine</i> is called, and itshould be released (if necessary) by applications.</font></P><P><font face="Verdana" size="2"> The progressthe overlapped <b>send</b> can be queried by using <a href="overlap.htm">getoverlappedresult</a>.</font></P><H4><font face="Verdana" size="2">See Also</font></H4><P><b><font face="Verdana" size="2"><a href="select.htm">select</a></font></b><font face="Verdana" size="2"><b>, <a href="recv.htm">recv</a>, <a href="sendfile.htm">sendfile</a>, <a href="recvfile.htm">recvfile</a>,</b><a href="overlap.htm"><b>getoverlappedresult</b></a></font></P></body></html>⌨️ 快捷键说明
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