Why is there no problem when debugging the breakpoint of my network file transfer program?

jucengge

UINT dataLength;
m_cSocket.Receive (&dataLength, 4);
CFile destFile ("e:\\11.xls", CFile :: modeCreate | CFile :: modeWrite | CFile :: typeBinary);
byte * data = new byte [dataLength];
m_cSocket.Receive (data, dataLength); destFile.Write (data, dataLength);
delete data;
destFile.Close ();
m_cSocket.Close ();
This paragraph is used to accept files and write files, but in the process of breakpoint debugging, m_cSocket.Receive (data, dataLength); You can see that the data of this sentence is correct, the file written is correct, but one The official operation is incorrect. It seems that the correct data is not received. The written documents are garbled. What is going on?

深蓝旅者

m_cSocket.Receive (data, dataLength); destFile.Write (data, dataLength); There is no guarantee that data of dataLength length will be read in one read operation, usually a loop is used to accept the data.
This is determined by the transmission speed of TCP. In the debug mode, single-step execution has enough time for the TCP transport layer to transmit all data.

zippodiy

Add sleep (100) to your sending thread;

houpengkn

On the first floor, please ask. TCP file transfer is generally a blocking call. If m_cSocket.Receive(data, dataLength) cannot receive data with the length of dataLength, and there is no error, will it return?