C Grammar

This is a small mistake, but takes me two hours to find out, take a look:

if (nbytes = recv(i, buf, sizeof buf, 0) <= 0) {
   ...
}

I find my program always has error and can’t find the reason. This line will make nbytes to be zero and of course this will make error.

The right version:

if ((nbytes = recv(i, buf, sizeof buf, 0)) <= 0) {
    ...
}