Re: Unexpected Access Violation when calling WriteFile()

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#13237

From: Remy Lebeau (TeamB)
Date: Tue, 21 Oct 2003 17:40

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"Fernando" <frr@easyjob.net> wrote in message
news:7bhapvkde568fjnf10ruf9t114kirltdr5@4ax.com...

>     LPDWORD bytesWritten;

That is wrong.  Anything in the Win32 API that starts with "LP" is a pointer
(formerly known as "long pointer", hense "LP").  So, essentially what is
happening is that you are declaring an uninitialized pointer and then
passing it to WriteFile() to fill in, but you did not allocate any actual
storage space for the value, thus the AV.  You need to change the
declaration to not use a pointer, and then use the '&' address operator when
passing it to WriteFile(), ie:

    bool writeToFile( HANDLE aFileHandle, void * data,  DWORD numOfBytes )
    {
        DWORD bytesWritten;
        return ::WriteFile( aFileHandle, data, numOfBytes, &bytesWritten,
NULL );
    }


Gambit

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Subject: Re: Unexpected Access Violation when calling WriteFile()
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