Managing SD Cards in User-Mode Applications

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The MultiMedia Card Association (MMCA) has defined a set of IOCTLs that allow user-mode applications to control operations on an SD storage stack. The IOCTLs are defined in the sffdisk.h header file provided with the Microsoft Windows SDK.

To use the IOCTLs, application software must get a handle to the volume of the target storage stack, as shown here:

    hVol = CreateFile(szVol,
        GENERIC_READ | GENERIC_WRITE,
        FILE_SHARE_WRITE | FILE_SHARE_DELETE,
        NULL,
        OPEN_EXISTING,
        FILE_ATTRIBUTE_NORMAL,
        NULL
    );
    if (hVol == INVALID_HANDLE_VALUE) {
        return GetLastError();
    }

Parameter szVol points to a NULL-terminated string that references the volume. After opening a handle, application software can send IOCTLs to the SD storage stack by calling DeviceIoControl.