At the first time I tried to use GetStdHandle but IOCP was not created. So I tried to use CreateFile to supply FILE_FLAG_OVERLAPPED for the console handle. Finally I concluded that IOCP cannot be used for console I/O.

Though I supply non-zero value for the completion key ( the 3rd arg. ), the result is the same. And I couldn't find restrictions for the value of the completion key mentioned in MSDN. And supplying INVALID_HANDLE_VALUE for the 1st arg is not compatible for NT 3.5 or below.

In the following short program, CreateIoCompletionPort fails and GetLastError says invalid handle was supplied. Return values from CreateFile is not INVALID_HANDLE_VALUE so I guess that IOCP doesn't accept handles for consoles. I just want to confirm that it is true or I made a mistake in this program. I intended to receive console inputs via IOCP. #include #include int main( void ) { HANDLE stdin_handle, iocp, stdout_handle; stdin_handle = CreateFile( "CON", GENERIC_READ, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL ); stdout_handle = CreateFile( "CON", GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL ); iocp = CreateIoCompletionPort( stdin_handle, NULL, 0, 1 ); if( iocp ) { CloseHandle( iocp ); puts( "O.K." ); } else { printf( "Error = %lu, stdin=%p, stdout=%p invalid_handle=%p\n", GetLastError(), stdin_handle, stdout_handle, INVALID_HANDLE_VALUE ); } return 0; } -- modified at 4:02 Tuesday 10th January, 2006