READ_REGISTER_UCHAR function (wdm.h)

The READ_REGISTER_UCHAR routine dereferences the supplied pointer, inserts a memory barrier, and reads a byte from the specified register address.

Syntax

UCHAR READ_REGISTER_UCHAR(
  [in] volatile UCHAR *Register
);

Parameters

[in] Register

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

Return value

READ_REGISTER_UCHAR returns the byte read from the specified register address.

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.

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

Requirements

Requirement	Value
Minimum supported client	Available starting with Windows 2000.
Target Platform	Universal
Header	wdm.h (include Wdm.h, Ntddk.h, Ntifs.h, Ioaccess.h, Miniport.h, Wudfwdm.h)
Library	NtosKrnl.lib
DLL	NtosKrnl.exe
IRQL	Any level (see Remarks section)