https://bugs.winehq.org/show_bug.cgi?id=42882 --- Comment #19 from Gregory McGill <arcadeshopper(a)gmail.com> --- according to the author: Opening a COM port in Windows is pretty standard and I use this in a lot of programs: wsprintf(ComPortName,"\\\\.\\COM%u", ComPort); hSerCom = CreateFile(ComPortName, GENERIC_READ|GENERIC_WRITE, 0, 0, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, 0); If this fails you get some messagebox: Can't open serial port <COM%u:> or: Can't create overlapped handle for <COM%u:> If you don't see this then the CreateFile function succeeded. no error messages in the program -- Do not reply to this email, post in Bugzilla using the above URL to reply. You are receiving this mail because: You are watching all bug changes.