error Incorrect Function

[andyg 101]

Hi there, I'm trying to do overlapped IO on the serial port, but since I changed from non-overlapped the readfile and writefile calls fail with error incorrect function I changed the following

m_ComPortHndl = CreateFile (sComPort,GENERIC_READ|GENERIC_WRITE,0,
NULL,OPEN_EXISTING,
FILE_FLAG_OVERLAPPED,NULL);

i.e. added the file flag overlapped and also added overlapped structures to the read/write calls

ReadFile( m_ComPortHndl, &nData, 1, &dwBytesRead, &ovRead)

any ideas why I might be getting this?? Andy

[andyg 101]

Scratch that it was because I wasn't initialising the overlapped structures to zero OVERLAPPED ov = {0}; Andy