Winsock2's select() on fd 0 (stdin) fails

Question

Using Winsock2 the code sequence below returns -1 (failure) for select().

#include 
#include 

        

Answer 1

This is expected behavior. As mentioned all over the documentation, winsock's select function only works on sockets, and stdin is not a socket.

If you had called WSAGetLastError, you undoubtedly would have found that the cause was

WSAENOTSOCK One of the descriptor sets contains an entry that is not a socket.

Try WSAEventSelect and WaitForMultipleObjectsEx; the latter can also wait on normal file handles as well as OVERLAPPED event objects from outstanding read operations on normal file handles.