buffered and neither io

NTDEV
1

Hi,
I’ve created a simple monolithic(non_layered
driver) which doesn’t do much. I’ve set the the
deviceobject flags to DO_BUFFERED_IO. yet when
processing IRP_MJ_READ, the only accessing the memory
is UserBuffer (and it works). The
AssoiatedIrp.Systembuffer has not been set.

I understood that neither io was an option but did not
know it was mandatory under certain situations. Can
anyone confirm this ?

Rajeev

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2

“Rajeev Rao” wrote in message news:xxxxx@ntdev…
> processing IRP_MJ_READ, the only accessing the memory
> is UserBuffer (and it works). The
> AssoiatedIrp.Systembuffer has not been set.
>

Neither I/O is never required.

The only time irp->AssociatedIrp.SystemBuffer is set to NULL, is when the
length of the usre buffer is specified as zero. In this case, just complete
the I/O request with success, setting IoStatus.Information to zero.

Peter
OSR