MmGetMdlByteCount macro (wdm.h)

The MmGetMdlByteCount macro returns the length, in bytes, of the buffer described by the specified MDL.

Syntax

C++

ULONG MmGetMdlByteCount(
  [in] PMDL Mdl
);

Mdl

A pointer to an MDL structure that describes the layout of a virtual memory buffer in physical memory. For more information, see Using MDLs.

MmGetMdlByteCount returns the length, in bytes, of the buffer described by Mdl.

Macro definition:

C++

#define MmGetMdlByteCount(Mdl)  ((Mdl)->ByteCount)

Callers of MmGetMdlByteCount can be running at any IRQL. Usually, callers are running at IRQL <= DISPATCH_LEVEL.

Requirement	Value
Target Platform	Desktop
Header	wdm.h (include Wdm.h, Ntddk.h, Ntifs.h)
IRQL	Any level (see Remarks section)
DDI compliance rules	MdlAfterReqCompletedIntIoctlA(kmdf), MdlAfterReqCompletedIoctlA(kmdf), MdlAfterReqCompletedReadA(kmdf), MdlAfterReqCompletedWriteA(kmdf)