C Specification

To flush ranges of non-coherent memory from the host caches, call:

// Provided by VK_VERSION_1_0
VkResult vkFlushMappedMemoryRanges(
    VkDevice                                    device,
    uint32_t                                    memoryRangeCount,
    const VkMappedMemoryRange*                  pMemoryRanges);


  • device is the logical device that owns the memory ranges.

  • memoryRangeCount is the length of the pMemoryRanges array.

  • pMemoryRanges is a pointer to an array of VkMappedMemoryRange structures describing the memory ranges to flush.


vkFlushMappedMemoryRanges guarantees that host writes to the memory ranges described by pMemoryRanges are made available to the host memory domain, such that they can be made available to the device memory domain via memory domain operations using the VK_ACCESS_HOST_WRITE_BIT access type.

Within each range described by pMemoryRanges, each set of nonCoherentAtomSize bytes in that range is flushed if any byte in that set has been written by the host since it was first host mapped, or the last time it was flushed. If pMemoryRanges includes sets of nonCoherentAtomSize bytes where no bytes have been written by the host, those bytes must not be flushed.

Unmapping non-coherent memory does not implicitly flush the host mapped memory, and host writes that have not been flushed may not ever be visible to the device. However, implementations must ensure that writes that have not been flushed do not become visible to any other memory.


The above guarantee avoids a potential memory corruption in scenarios where host writes to a mapped memory object have not been flushed before the memory is unmapped (or freed), and the virtual address range is subsequently reused for a different mapping (or memory allocation).

If VkPhysicalDeviceVulkanSC10Properties::deviceNoDynamicHostAllocations is VK_TRUE, vkFlushMappedMemoryRanges must not return VK_ERROR_OUT_OF_HOST_MEMORY.

Valid Usage (Implicit)
  • VUID-vkFlushMappedMemoryRanges-device-parameter
    device must be a valid VkDevice handle

  • VUID-vkFlushMappedMemoryRanges-pMemoryRanges-parameter
    pMemoryRanges must be a valid pointer to an array of memoryRangeCount valid VkMappedMemoryRange structures

  • VUID-vkFlushMappedMemoryRanges-memoryRangeCount-arraylength
    memoryRangeCount must be greater than 0

Return Codes
On success, this command returns

On failure, this command returns


See Also

Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

Copyright 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0