C Specification

If the pNext chain of a VkDescriptorSetLayoutSupport structure includes a VkDescriptorSetVariableDescriptorCountLayoutSupport structure, then that structure returns additional information about whether the descriptor set layout is supported.

// Provided by VK_VERSION_1_2
typedef struct VkDescriptorSetVariableDescriptorCountLayoutSupport {
    VkStructureType    sType;
    void*              pNext;
    uint32_t           maxVariableDescriptorCount;
} VkDescriptorSetVariableDescriptorCountLayoutSupport;

or the equivalent

// Provided by VK_EXT_descriptor_indexing
typedef VkDescriptorSetVariableDescriptorCountLayoutSupport VkDescriptorSetVariableDescriptorCountLayoutSupportEXT;


  • sType is a VkStructureType value identifying this structure.

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

  • maxVariableDescriptorCount indicates the maximum number of descriptors supported in the highest numbered binding of the layout, if that binding is variable-sized. If the highest numbered binding of the layout has a descriptor type of VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK then maxVariableDescriptorCount indicates the maximum byte size supported for the binding, if that binding is variable-sized.


If the VkDescriptorSetLayoutCreateInfo structure specified in vkGetDescriptorSetLayoutSupport::pCreateInfo includes a variable-sized descriptor, then supported is determined assuming the requested size of the variable-sized descriptor, and maxVariableDescriptorCount is set to the maximum size of that descriptor that can be successfully created (which is greater than or equal to the requested size passed in). If the VkDescriptorSetLayoutCreateInfo structure does not include a variable-sized descriptor, or if the VkPhysicalDeviceDescriptorIndexingFeatures::descriptorBindingVariableDescriptorCount feature is not enabled, then maxVariableDescriptorCount is set to zero. For the purposes of this command, a variable-sized descriptor binding with a descriptorCount of zero is treated as having a descriptorCount of four if descriptorType is VK_DESCRIPTOR_TYPE_INLINE_UNIFORM_BLOCK, or one otherwise, and thus the binding is not ignored and the maximum descriptor count will be returned. If the layout is not supported, then the value written to maxVariableDescriptorCount is undefined.

Valid Usage (Implicit)
  • VUID-VkDescriptorSetVariableDescriptorCountLayoutSupport-sType-sType

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