[wdmaudiodev] Re: Bug in MSVAD sample, or misunderstanding?
- From: "Chris Edgington" <chris.edgington@xxxxxxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Sat, 5 Oct 2002 18:00:08 -0500
I said I think the pointer should be set to NULL. As is it now, we could
call ExFreePool with a pointer to a block of memory that was already
freed. Setting m_pvDmaBuffer to NULL after freeing it would not allow
that to happen.
Maybe I'm misunderstanding what you're saying, I don't see the quote you
refer to in MSDN.
-Chris
> -----Original Message-----
> From: wdmaudiodev-bounce@xxxxxxxxxxxxx
> [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Chun-Yu
> Sent: Saturday, October 05, 2002 5:55 PM
> To: wdmaudiodev@xxxxxxxxxxxxx
> Subject: [wdmaudiodev] Re: Bug in MSVAD sample, or misunderstanding?
>
>
>
> Ah, but from the MSDN Library - "If memblock is NULL, the pointer is
> ignored and free immediately returns."
>
> So it doesn't hurt to call free on a NULL pointer - it just won't do
> anything.
>
> Chun-Yu
>
> On Sat, 5 Oct 2002, Chris Edgington wrote:
>
> >
> > In the msvad sample in the XP DDK, in basedma.cpp, the
> following code
> > exists for the FreeBuffer method:
> >
> > if ( m_pvDmaBuffer )
> > {
> > ExFreePool( m_pvDmaBuffer );
> > m_ulDmaBufferSize = 0;
> > }
> >
> > Am I missing something, or should m_pvDmaBuffer be set to
> NULL after the
> > free? This has the potential of being called to free a NULL pointer,
> > right?
> >
> > Thanks,
> > -Chris
> >
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