VkDescriptorPoolCreateInfo(3)

# VkDescriptorPoolCreateInfo(3) Manual Page

## Name

VkDescriptorPoolCreateInfo - Structure specifying parameters of a newly created descriptor pool

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## C Specification

Additional information about the pool is passed in a `VkDescriptorPoolCreateInfo` structure:

    typedef struct VkDescriptorPoolCreateInfo {
        VkStructureType                sType;
        const void*                    pNext;
        VkDescriptorPoolCreateFlags    flags;
        uint32_t                       maxSets;
        uint32_t                       poolSizeCount;
        const VkDescriptorPoolSize*    pPoolSizes;
    } VkDescriptorPoolCreateInfo;

## Members

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to an extension-specific structure.

- `flags` is a bitmask of VkDescriptorPoolCreateFlagBits specifying certain supported operations on the pool.

- `maxSets` is the maximum number of descriptor sets that can be allocated from the pool.

- `poolSizeCount` is the number of elements in `pPoolSizes`.

- `pPoolSizes` is a pointer to an array of VkDescriptorPoolSize structures, each containing a descriptor type and number of descriptors of that type to be allocated in the pool.

## Description

If multiple `VkDescriptorPoolSize` structures appear in the `pPoolSizes` array then the pool will be created with enough storage for the total number of descriptors of each type.

Fragmentation of a descriptor pool is possible and may lead to descriptor set allocation failures. A failure due to fragmentation is defined as failing a descriptor set allocation despite the sum of all outstanding descriptor set allocations from the pool plus the requested allocation requiring no more than the total number of descriptors requested at pool creation. Implementations provide certain guarantees of when fragmentation must not cause allocation failure, as described below.

If a descriptor pool has not had any descriptor sets freed since it was created or most recently reset then fragmentation must not cause an allocation failure (note that this is always the case for a pool created without the `VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT` bit set). Additionally, if all sets allocated from the pool since it was created or most recently reset use the same number of descriptors (of each type) and the requested allocation also uses that same number of descriptors (of each type), then fragmentation must not cause an allocation failure.

If an allocation failure occurs due to fragmentation, an application can create an additional descriptor pool to perform further descriptor set allocations.

If `flags` has the `VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT` bit set, descriptor pool creation may fail with the error `VK_ERROR_FRAGMENTATION` if the total number of descriptors across all pools (including this one) created with this bit set exceeds `maxUpdateAfterBindDescriptorsInAllPools`, or if fragmentation of the underlying hardware resources occurs.

Valid Usage

- `maxSets` must be greater than `0`

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_DESCRIPTOR_POOL_CREATE_INFO`

- `pNext` must be `NULL` or a pointer to a valid instance of VkDescriptorPoolInlineUniformBlockCreateInfoEXT

- The `sType` value of each struct in the `pNext` chain must be unique

- `flags` must be a valid combination of VkDescriptorPoolCreateFlagBits values

- `pPoolSizes` must be a valid pointer to an array of `poolSizeCount` valid VkDescriptorPoolSize structures

- `poolSizeCount` must be greater than `0`

## See Also

VkDescriptorPoolCreateFlags, VkDescriptorPoolSize, VkStructureType, vkCreateDescriptorPool

## 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 (c) 2014-2020 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.