WdfMemoryCopyFromBuffer function (wdfmemory.h)

Article
02/22/2024

[Applies to KMDF and UMDF]

The WdfMemoryCopyFromBuffer method copies the contents of a specified source buffer into a specified memory object's buffer.

Syntax

NTSTATUS WdfMemoryCopyFromBuffer(
  [in] WDFMEMORY DestinationMemory,
  [in] size_t    DestinationOffset,
  [in] PVOID     Buffer,
  [in] size_t    NumBytesToCopyFrom
);

Parameters

[in] DestinationMemory

A handle to a framework memory object that represents the destination buffer.

[in] DestinationOffset

An offset, in bytes, from the beginning of the destination buffer. The copy operation begins at the specified offset in the destination buffer.

[in] Buffer

A pointer to a source buffer.

[in] NumBytesToCopyFrom

The number of bytes to copy from the source buffer to the destination buffer. This value must not be greater than the size of the source buffer.

Return value

WdfMemoryCopyFromBuffer returns STATUS_SUCCESS if the operation succeeds. Otherwise, this method might return one of the following values:

Return code	Description
STATUS_INVALID_PARAMETER	An invalid parameter was detected.
STATUS_INVALID_BUFFER_SIZE	The byte offset that the DestinationOffset parameter specified was too large.
STATUS_BUFFER_TOO_SMALL	The size of the destination buffer that the DestinationOffset parameter specified, starting at the destination offset, was greater than the NumBytesToCopyFrom parameter.

This method also might return other NTSTATUS values.

A bug check occurs if the driver supplies an invalid object handle.

Remarks

The framework verifies that the destination buffer is large enough to receive the amount of data that the NumBytesToCopyFrom parameter specifies.

For more information about framework memory objects, see Using Memory Buffers.

If the source or destination buffer was allocated from the pageable memory pool, the WdfMemoryCopyFromBuffer method must be called at IRQL <= APC_LEVEL. Otherwise, the method can be called at any IRQL.

Examples

The following code example obtains a handle to the framework memory object that represents an I/O request's output buffer, and then it copies the contents of another buffer into the I/O request's output buffer.

WDFMEMORY  memoryBuffer;
NTSTATUS  status;

status = WdfRequestRetrieveOutputMemory(
                                        Request,
                                        &memoryBuffer
                                        );
if (!NT_SUCCESS(status)) {
    goto Error;
}
status = WdfMemoryCopyFromBuffer(
                                 memoryBuffer,
                                 0,
                                 deviceContext->Buffer,
                                 Length
                                 );
if (!NT_SUCCESS(status)) {
    goto Error;
}

Requirements

Requirement	Value
Target Platform	Universal
Minimum KMDF version	1.0
Minimum UMDF version	2.0
Header	wdfmemory.h (include Wdf.h)
Library	Wdf01000.sys (KMDF); WUDFx02000.dll (UMDF)
IRQL	Any level (see Remarks section)
DDI compliance rules	BufAfterReqCompletedIntIoctlA(kmdf), BufAfterReqCompletedIoctlA(kmdf), BufAfterReqCompletedReadA(kmdf), BufAfterReqCompletedWriteA(kmdf), DriverCreate(kmdf), MemAfterReqCompletedIntIoctlA(kmdf), MemAfterReqCompletedIoctlA(kmdf), MemAfterReqCompletedReadA(kmdf), MemAfterReqCompletedWriteA(kmdf)