Errno 35 (EAGAIN) returned on recv call

Question

I have a socket which waits for recv and then after receiving data, sends data forward for processing. However, then it again goes for recv, and this time it receives nothing returns -1 and when printed the errno it prints 35 (which is EAGAIN).

This happens only on MAC OS Lion operating system, for other OS this runs perfectly fine

do{
 rc = recv(i, buffer, sizeof(buffer), 0);
 if (rc < 0){
      printf("err code %d", errno); 
 }
 if(rc == 0){ 
      //Code for processing the data in buffer 
      break; 
 } 
      ....
}while(1);

EDIT: Corrected indentation and errno

Answer 1

You either set the socket to non-blocking mode or enabled the receive timeout. Here's from recv(2) on a mac:

The calls fail if:

[EAGAIN] The socket is marked non-blocking, and the receive operation would block, or a receive timeout had been set, and the timeout expired before data were received.

Edit 0:

Hmm, apologies for quoting again. This time from intro(2):

11 EDEADLK Resource deadlock avoided. An attempt was made to lock a system resource that would have resulted in a deadlock situation.

...

35 EAGAIN Resource temporarily unavailable. This is a temporary condition and later calls to the same routine may complete normally.

Just use strerror(3) to figure out the actual issue.