When sending in Multicast IP mode over an ATM or Ethernet network via an UDP socket of type SOCKET, sendto() sometimes returns the WSA error 997 ("Overlapped I/O operation is in progress"), whether or not the socket is set to blocking or non blocking mode. Errors frequency seems to follow sendto() frequency.
What is the meaning of this error, and is there a workaround?
OS used: NT 4.0 + service pack 4. Winsock v 2.0