C Specification

If the pNext chain of a VkDescriptorSetAllocateInfo structure includes a VkDescriptorSetVariableDescriptorCountAllocateInfo structure, then that structure includes an array of descriptor counts for variable descriptor count bindings, one for each descriptor set being allocated.

The VkDescriptorSetVariableDescriptorCountAllocateInfo structure is defined as:

// Provided by VK_VERSION_1_2
typedef struct VkDescriptorSetVariableDescriptorCountAllocateInfo {
    VkStructureType    sType;
    const void*        pNext;
    uint32_t           descriptorSetCount;
    const uint32_t*    pDescriptorCounts;
} VkDescriptorSetVariableDescriptorCountAllocateInfo;

or the equivalent

// Provided by VK_EXT_descriptor_indexing
typedef VkDescriptorSetVariableDescriptorCountAllocateInfo VkDescriptorSetVariableDescriptorCountAllocateInfoEXT;


  • sType is the type of this structure.

  • pNext is NULL or a pointer to a structure extending this structure.

  • descriptorSetCount is zero or the number of elements in pDescriptorCounts.

  • pDescriptorCounts is a pointer to an array of descriptor counts, with each member specifying the number of descriptors in a variable descriptor count binding in the corresponding descriptor set being allocated.


If descriptorSetCount is zero or this structure is not included in the pNext chain, then the variable lengths are considered to be zero. Otherwise, pDescriptorCounts[i] is the number of descriptors in the variable count descriptor binding in the corresponding descriptor set layout. If the variable count descriptor binding in the corresponding descriptor set layout has a descriptor type of VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK_EXT then pDescriptorCounts[i] specifies the binding’s capacity in bytes. If VkDescriptorSetAllocateInfo::pSetLayouts[i] does not include a variable count descriptor binding, then pDescriptorCounts[i] is ignored.

Valid Usage
  • If descriptorSetCount is not zero, descriptorSetCount must equal VkDescriptorSetAllocateInfo::descriptorSetCount

  • If VkDescriptorSetAllocateInfo::pSetLayouts[i] has a variable descriptor count binding, then pDescriptorCounts[i] must be less than or equal to the descriptor count specified for that binding when the descriptor set layout was created

Valid Usage (Implicit)

  • If descriptorSetCount is not 0, pDescriptorCounts must be a valid pointer to an array of descriptorSetCount uint32_t values

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 (c) 2014-2020 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0