recv after select

[hanlei0000000009]

timeval timeOut;
timeOut.tv_sec = 0;
timeOut.tv_usec = 3000*1000;

fd_set fdread, fdExcept;
FD_ZERO(&fdread);
FD_ZERO(&fdExcept);
FD_SET(sock,&fdread);
FD_SET(sock,&fdExcept);

int iRet = 0;
iRet = select(0, &fdread, NULL, &fdExcept, &timeOut);

if(FD_ISSET(sock,&fdread))
{
//can read
int iRecv = recv(sock, strRecv, 512*1024, 0);// extern char strRecv[512*1024]
/*
If receive buffer has been received 1024 BYTE, recv() no problem. after recv(), iRecv equals 1024.
If receive buffer has been received a lot data, 50*1024 for example, recv() has problem.
strRecv has not got data what is from send() and iRecv not equals 50*1024.
notes: If no select(), only use recv(), that no problem when recv() 50*1024 BYTE
*/
}

[erwin1984]

use: while( .... ) { select( ... ); recv( ... ); } to receive a lot data. because of the large TCP data block will be splitted to small pieces during transfer, the recv()'s size may not equal to send()'s size at one time.

Erwin Yuan

[Mark Salsbery]

As Erwin mentions, you can never assume you'll get all the bytes you request in a single call to recv(). You must keep calling recv() until you get the number of bytes you're expecting. Mark

Mark Salsbery Microsoft MVP - Visual C++ :java: