READ_REGISTER_BUFFER_UCHAR function (wdm.h)

The READ_REGISTER_BUFFER_UCHAR routine dereferences the supplied pointer, inserts a memory barrier, and reads a set of bytes from the specified register address into a buffer.

Syntax

void READ_REGISTER_BUFFER_UCHAR(
  [in]  volatile UCHAR *Register,
  [out] PUCHAR         Buffer,
  [in]  ULONG          Count
);

Parameters

[in] Register

Pointer to the register, which must be a mapped range in memory space.

[out] Buffer

Pointer to a buffer into which an array of UCHAR values is read.

[in] Count

Specifies the number of bytes to be read into the buffer.

Return value

None

Remarks

This routine inserts a memory barrier into your code. This barrier guarantees that every operation that appears in the source code before the call to this routine will complete before any operation that appears after the call.

For more info about memory barriers, see KeMemoryBarrier.

The size of the buffer must be large enough to contain at least the specified number of bytes.

Callers of READ_REGISTER_BUFFER_UCHAR can be running at any IRQL, assuming the Buffer is resident and the Register is resident, mapped device memory.

Requirements