There must be something very simple I'm overlooking:

I have an AVStream/BDA property handler for a GET property with a
variable-sized output buffer:

NTSTATUS MyPropertyHandler_Get_ListPIDs(
IN PIRP Irp,
IN PKSPROPERTY Property,
IN PVOID OutputBuffer)

Obviously, I need to know the size of the output buffer to be able to tell
if my data will fit in it (or return STATUS_BUFFER_OVERFLOW if it won't).
But where do I get it from? I suppose I could retrieve the I/O stack
location from the IRP and look at it, but isn't there an "AVStream" or
"BDA" way to do this?

Regards,«
--
Robert Schlabbach
e-mail: robert_s@gmx.net
Berlin, Germany

This is what I use

ULONG ulOutputSize = IoGetCurrentIrpStackLocation(
pIrp )->Parameters.DeviceIoControl.OutputBufferLength;

Although I don't think it is really necessary. The class driver should do
checking for you and the size that it assumes is the one that it gets from
KSPROPERTY_ITEM for the property in question.

For myself I do the checking anyway. Better be safe than sorry, I guess. Old
habits die hard.

-- Max.



"Robert Schlabbach" <robert_s@gmx.net> wrote in message
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