vkEnumeratePhysicalDevices

To retrieve a list of physical device objects representing the physical devices installed in the system, call:

VkResult vkEnumeratePhysicalDevices(
    VkInstance instance,
    uint32_t* pPhysicalDeviceCount,
    VkPhysicalDevice* pPhysicalDevices);

• instance is a handle to a Vulkan instance previously created with vkCreateInstance.
• pPhysicalDeviceCount is a pointer to an integer related to the number of physical devices available or queried, as described below.
• pPhysicalDevices is either NULL or a pointer to an array of VkPhysicalDevice handles.

If pPhysicalDevices is NULL, then the number of physical devices available is returned in pPhysicalDeviceCount. Otherwise, pPhysicalDeviceCount must point to a variable set by the application to the number of elements in the pPhysicalDevices array, and on return the variable is overwritten with the number of handles actually written to pPhysicalDevices. If pPhysicalDeviceCount is less than the number of physical devices available, at most pPhysicalDeviceCount structures will be written, and VK_INCOMPLETE will be returned instead of VK_SUCCESS, to indicate that not all the available physical devices were returned.