COM port CreateFile -> Close Handle Works great, unless the USB device is unplugged,

This is a discussion on COM port CreateFile -> Close Handle Works great, unless the USB device is unplugged, within the Windows Programming forums, part of the Platform Specific Boards category; COM port CreateFile -> Close Handle Works great, unless the USB device is unplugged, then it can not be reopened ...

  1. #1
    Registered User
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    Feb 2009
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    3

    COM port CreateFile -> Close Handle Works great, unless the USB device is unplugged,

    COM port CreateFile -> Close Handle Works great, unless the USB device is unplugged, then it can not be reopened without restarted computer

    If usb device is ever unplugged, i get a return of a ERROR_FILE_NOT_FOUND from Create handle, and cannot continue unless the computer is restarted

    this happens when I am connected to the device and when I am not connected, just if it is unplugged and replugged in

    (this works awesome, and can continue to create and close, until the device is unplugged from the computer and plugged back in)
    Code:
    hcomms[hcommcount-1] = CreateFile(com, 
     GENERIC_READ | GENERIC_WRITE,
     0,
     0,
     OPEN_EXISTING,
     FILE_ATTRIBUTE_NORMAL /*| FILE_FLAG_OVERLAPPED*/,
     0);
    
     if ( hcomms[hcommcount-1] == INVALID_HANDLE_VALUE)
     {
     DWORD error = GetLastError();
     return -1;
     }
    
    
    if (!CloseHandle(hcomms[cindx]))
     {
     errorCode = GetLastError();
     }

  2. #2
    Registered User Codeplug's Avatar
    Join Date
    Mar 2003
    Posts
    4,650
    Does any known-to-work software reproduce the issue? Like hyperterminal etc...

    If it only occurs when you're running your code - then your code is probably at fault. Otherwise it would be a buggy driver.

    gg

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