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ZeroDeviceMemory function

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The ZeroDeviceMemory function sets the contents of a buffer to zeros without interference from compiler optimizations in situations where the developer needs to additionally be sure that alignment faults will not be generated when accessing device memory.

Important

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Parameters

Param Destination [out]

A pointer to the starting address of the block of memory to fill with zeros.

Param Length [in]

The size of the block of memory to fill with zeros, in bytes.

Syntax

volatile void*
  ZeroDeviceMemory (
    _Out_writes_bytes_all_(Length) volatile void* Destination,
    SIZE_T Length
  );

Remarks

This API is a convenience wrapper around FillDeviceMemory. See the remarks of FillDeviceMemory for more information.

Note

This function works on all versions of Windows, not just the latest. You need to consume the latest SDK to get the function declaration from the winbase.h header. You also need the library (volatileaccessu.lib) from the latest SDK. However, the resulting binary will run fine on older versions of Windows.

Example

// In this scenario we are setting data on memory mapped
// as "device memory" (i.e. memory not backed by RAM) to the value zero. On
// some platforms like ARM64, device memory cannot tolerate
// memory accesses that are not naturally aligned (i.e. a 4-byte
// load must be 4-byte aligned). Functions like memset, FillMemory,
// and even FillVolatileMemory may perform unaligned memory accesses
// because it is typically faster to do this.
// To ensure only naturally aligned accesses happen, use FillDeviceMemory.
//
// ZeroDeviceMemory is an wrapper around FillDeviceMemory that sets the memory
// to zero.

ZeroDeviceMemory(DeviceMemoryBuffer, 100);

Requirements

Minimum supported client: Windows 11 Insider Preview Build TBD

Header: winbase.h (include Winbase.h)

Kernel-mode library: volatileaccessk.lib

User-mode library: volatileaccessu.lib

See also