vkEnumerateInstanceExtensions

vkEnumerateInstanceExtensionProperties is a Vulkan API function used to query the set of available Vulkan instance extensions. It may return global extensions or extensions provided by a specific layer, enabling applications to discover optional features that can be enabled during instance creation.

The function signature is vkEnumerateInstanceExtensionProperties(const char* pLayerName, uint32_t* pPropertyCount, VkExtensionProperties* pProperties). The pLayerName parameter selects the layer for which extensions are returned; if NULL, the call queries global instance extensions. pPropertyCount on input specifies the size of the pProperties array, and on output returns the number of available extension properties. If pProperties is NULL, the function only returns the total number of extensions in pPropertyCount. If pLayerName is non-NULL and the named layer is not present, VK_ERROR_LAYER_NOT_PRESENT may be returned.

VkExtensionProperties is the structure that describes an extension, containing the extensionName (null-terminated string) and specVersion. The typical usage pattern is a two-step process: first call with pProperties set to NULL to obtain the count of available extensions, then allocate an array of VkExtensionProperties of that size and call again to fill the array. If the provided array is insufficient to hold all results, VK_INCOMPLETE may be returned, and pPropertyCount will hold the total number of extensions.

This function is commonly invoked during application initialization to determine which instance extensions to enable when creating a Vulkan instance. It complements similar enumeration functions for instance layers and device extensions.