Mine

#ifdef WIN32
void SetSocketNonBlocking(int socket)
{
    ULONG NonBlock = 1;
     if (ioctlsocket(socket, FIONBIO, &NonBlock) == SOCKET_ERROR)
     {
          printf("ioctlsocket() failed (socket cannot set to non-blocking)\n");
          return;
     }
}
#else
void SetSocketNonBlocking(int socket)
{
    ULONG NonBlock = 1;
     if (fcntl(socket, 4, 0x4000)) == SOCKET_ERROR)
     {
          printf("fcntl() failed (socket cannot set to non-blocking)\n");
          return;
     }
}
#endif