📄 t-data.htm
字号:
<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 </i></font><i> <font face="Verdana" size="2">Tutorial</font></i></td> </tr></table><h1><font face="Verdana" size="4">Transfer Data using UDT</font></h1><p><font face="Verdana" size="2">UDT supports both blocking and non-blocking IO, in traditional (same as socket API) or overlapped way.</font></p><h4><font face="Verdana" size="2">Blocking Sending</font></h4><p><font face="Verdana" size="2">A blocking UDT<a href="send.htm">send</a> call will be blocked until there is enough buffer in the sending queue. The user buffer is copied into the protocol buffer. If multiple <a href="send.htm">send</a> calls are used in multi-thread applications, all calls will be blocked and released one by one as the buffers in the waiting queue are sent out. However, the release order is NOT guaranteed by UDT, but depends on the thread mechanism on specific operating systems.</font></p><p><font face="Verdana" size="2">In overlapped sending, UDT does NOT copy the user data into the memory, but send the data directly into the network. The sending will not return until all data has been successfully received.</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 face="Courier New" size="1">void DeleteBuf(char* buf, int) {delete [] buf;}</font></p> <p style="margin-top: 0; margin-bottom: 0"> <font face="Courier New" size="1">...</font></p> <p style="margin-top: 0; margin-bottom: 0"> </p> <p style="margin-top: 0; margin-bottom: 0"> <font face="Courier New" size="1">// blocking sending</font></p> <p style="margin-top: 0; margin-bottom: 0"> <font face="Courier New" size="1">if (UDT::ERROR == UDT::send(usock, buffer, size, 0))<br> {<br> cout << "send: " << UDT::getlasterror().getErrorMessage();<br> return 0;<br> }</font></p> <p style="margin-top: 0; margin-bottom: 0"> </p> <p style="margin-top: 0; margin-bottom: 0"> <font face="Courier New" size="1">// blocking overlapped sending</font></p> <p style="margin-top: 0; margin-bottom: 0"> <font face="Courier New" size="1">if (UDT::ERROR == UDT::send(usock, buffer, size, 0, &handle, DeleteBuf))<br> {<br> cout << "send: " << UDT::getlasterror().getErrorMessage();<br> return 0;<br> }</font></p></td> </tr></table><h4><font face="Verdana" size="2">Blocking Receiving</font></h4><p><font size="2" face="Verdana">In the traditional blocking receiving, a UDT <a href="recv.htm">recv</a> call is blocked until there is any data available for reading in the UDT protocol buffer. The data is copied from the protocol buffer into the user buffer.</font></p><p><font size="2" face="Verdana">In overlapped receiving, the user buffer is linked onto the protocol buffer and new data will be written directly into the user buffer. Thus, the <a href="recv.htm">recv</a> call will not return until the buffer is fulfilled. Note that this receiving mode may block infinitely until the desired amount of data is received or the connection is broken.</font></p><h4><font face="Verdana" size="2">Non-Blocking Sending</font></h4><p><font size="2" face="Verdana">Non-blocking sending will return immediately no matter if the sending succeed or not. A successful sending copies the user data into the protocol buffer, which will be sent out in background.</font></p><p><font face="Verdana" size="2">Overlapped non-blocking sending does not copy user buffer into the protocol buffer, and does not wait the sending to complete. A function pointer may be passed as parameter so that the user parameter can be automatically processed (e.g., release). In this mode, the buffer cannot be touched until the sending is completed. To test if a certain non-blocking sending is completed, use <a href="overlap.htm">getoverlappedresult</a>.</font></p><p><font face="Verdana" size="2">It may be necessary to use non-blocking sending together with <a href="select.htm">select</a> call.</font></p><h4><font face="Verdana" size="2">Non-Blocking Receiving</font></h4><p><font face="Verdana" size="2">Non-blocking receiving will return immediately with any available data no more than the size appointed in the parameter.</font></p><p><font face="Verdana" size="2">In overlapped mode, non-blocking receiving will not return any data to the user, instead, it process the user buffer using the function in the parameter after the user buffer is fulfilled.</font></p><p><font face="Verdana" size="2">Note that at most one non-blocking overlapped receiving is allowed in the current implementation.</font></p></body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -