VkDescriptorPoolCreateFlagBits

Bits which can be set in VkDescriptorPoolCreateInfo::flags, enabling operations on a descriptor pool, are:

typedef enum VkDescriptorPoolCreateFlagBits {
    VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT = 0x00000001,
} VkDescriptorPoolCreateFlagBits;

• VK_DESCRIPTOR_POOL_CREATE_FREE_DESCRIPTOR_SET_BIT specifies that descriptor sets can return their individual allocations to the pool, i.e. all of vkAllocateDescriptorSets, vkFreeDescriptorSets, and vkResetDescriptorPool are allowed. Otherwise, descriptor sets allocated from the pool must not be individually freed back to the pool, i.e. only vkAllocateDescriptorSets and vkResetDescriptorPool are allowed.
• VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT specifies that descriptor sets allocated from this pool can include bindings with the VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT bit set. It is valid to allocate descriptor sets that have bindings that do not set the VK_DESCRIPTOR_BINDING_UPDATE_AFTER_BIND_BIT bit from a pool that has VK_DESCRIPTOR_POOL_CREATE_UPDATE_AFTER_BIND_BIT set.
• VK_DESCRIPTOR_POOL_CREATE_HOST_ONLY_BIT_EXT specifies that this descriptor pool and the descriptor sets allocated from it reside entirely in host memory and cannot be bound. Similar to descriptor sets allocated without this flag, applications can copy-from and copy-to descriptors sets allocated from this descriptor pool. Descriptor sets allocated from this pool are partially exempt from the external synchronization requirement in vkUpdateDescriptorSetWithTemplateKHR and vkUpdateDescriptorSets. Descriptor sets and their descriptors can be updated concurrently in different threads, though the same descriptor must not be updated concurrently by two threads.
• VK_DESCRIPTOR_POOL_CREATE_ALLOW_OVERALLOCATION_SETS_BIT_NV specifies that the implementation should allow the application to allocate more than VkDescriptorPoolCreateInfo::maxSets descriptor set objects from the descriptor pool as available resources allow. The implementation may use the maxSets value to allocate the initial available sets, but using zero is permitted.
• VK_DESCRIPTOR_POOL_CREATE_ALLOW_OVERALLOCATION_POOLS_BIT_NV specifies that the implementation should allow the application to allocate more descriptors from the pool than was specified by the VkDescriptorPoolSize::descriptorCount for any descriptor type as specified by VkDescriptorPoolCreateInfo::poolSizeCount and VkDescriptorPoolCreateInfo::pPoolSizes, as available resources allow. The implementation may use the descriptorCount for each descriptor type to allocate the initial pool, but the application is allowed to set the poolSizeCount to zero, or any of the descriptorCount values in the pPoolSizes array to zero.