# VkMemoryUnmapFlagBits(3) Manual Page

## Name

VkMemoryUnmapFlagBits - Bitmask specifying additional parameters of a memory unmap

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## C Specification

Bits which can be set in VkMemoryUnmapInfo::`flags`, specifying additional properties of a memory unmap, are:

    // Provided by VK_VERSION_1_4
    typedef enum VkMemoryUnmapFlagBits {
      // Provided by VK_EXT_map_memory_placed
        VK_MEMORY_UNMAP_RESERVE_BIT_EXT = 0x00000001,
    } VkMemoryUnmapFlagBits;

or the equivalent

    // Provided by VK_KHR_map_memory2
    typedef VkMemoryUnmapFlagBits VkMemoryUnmapFlagBitsKHR;

## Description

- `VK_MEMORY_UNMAP_RESERVE_BIT_EXT` requests that virtual address range currently occupied by the memory map remain reserved after the vkUnmapMemory2 call completes. Future system memory map operations or calls to vkMapMemory or vkMapMemory2 will not return addresses in that range unless the range has since been unreserved by the client or the mapping is explicitly placed in that range by calling vkMapMemory2 with `VK_MEMORY_MAP_PLACED_BIT_EXT`, or doing the system memory map equivalent. When `VK_MEMORY_UNMAP_RESERVE_BIT_EXT` is set, the memory unmap operation may fail, in which case the memory object will remain host mapped and vkUnmapMemory2 will return `VK_ERROR_MEMORY_MAP_FAILED`.

## See Also

VK_KHR_map_memory2, VK_VERSION_1_4, VkMemoryUnmapFlags

## 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

Copyright 2014-2025 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0