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USB Flash memory arrive/remove notification

By gcfreddy
Feb 8, 2006
  1. Hi everybody,

    I'm developing a application to run over Windows XP embedded and have some troubles with
    the usb flash memory handling.

    My application needs to do some job when a USB flash memory is Removed/Inserted in any

    available USB port.

    I am using the Windows Messages WM_DEVICECHANGE with the flags DBT_DEVICEARRIVAL and

    DBT_DEVICEREMOVECOMPLETE. It works very well after the the usb flash memory has been used in

    the computer where the application run.

    But, When the application is running and a flash memory is inserted by first time in the

    computer, Windows sends the WM_DEVICECHANGE-DBT_DEVICEARRIVAL followed by a WM_DEVICECHANGE

    -DBT_DEVICEREMOVECOMPLETE and other WM_DEVICECHANGE-DBT_DEVICEARRIVAL. In this case, the

    behavior of the application is apparently wrong because it process the Device Remove message

    and the flash memory is still inserted in the USB Port.

    Is there any diference between the WM_DEVICECHANGE-DBT_DEVICEARRIVAL message sent by Windows

    the first time that a flash memory is inserted in a computer?

    Does anyone know how to identify this first WM_DEVICECHANGE-DBT_DEVICEARRIVAL?

    I have another issue, sometimes take few seconds to detect the WM_DEVICECHANGE-

    DBT_DEVICEARRIVAL or WM_DEVICECHANGE-DBT_DEVICEREMOVECOMPLETE. is this a isolated issue or

    any of you have seen something like that?

    Thanks for any help
     
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