Vulkan-Docs/doc/specs/vulkan/man/vkGetPhysicalDeviceMemoryProperties.txt

vkGetPhysicalDeviceMemoryProperties(3)
======================================

Name
----
vkGetPhysicalDeviceMemoryProperties - Reports memory information for the specified physical device.

C Specification
---------------

include::../protos/vkGetPhysicalDeviceMemoryProperties.txt[]

Parameters
----------

pname:physicalDevice::
    A handle to the physical device about which information is to be retrieved.

pname:pMemoryProperties::
    A pointer to a structure that is to receive the memory information.

Description
-----------

fname:vkGetPhysicalDeviceMemoryProperties retrieves information about the memory of the physical
device whose handle is given in pname:physicalDevice. pname:pMemoryProperties should point to an
instance of the sname:VkPhysicalDeviceMemoryProperties structure, into which will be stored the
information about the device. The definition of sname:VkPhysicalDeviceMemoryProperties is as
follows.

include::../structs/VkPhysicalDeviceMemoryProperties.txt[]

* pname:memoryTypeCount will be filled with the number of memory types supported by
the device.

* pname:memoryTypes is an array of ename:VK_MAX_MEMORY_TYPES instances of the
slink:VkMemoryType structures. Upon return from fname:vkGetPhysicalDeviceMemoryProperties,
the first pname:memoryTypeCount elements of pname:memoryTypes will contain valid data.

* pname:memoryHeapCount will be filled with the number of memory heaps supported by
the device.

* pname:memoryHeaps is an array of ename:VK_MAX_MEMORY_HEAPS slink:VkMemoryHeap
structures which describe the heaps available to the device.

The definition of the slink:VkMemoryType structure is as follows:

include::../structs/VkMemoryType.txt[]

* pname:propertyFlags is a bitfield made up from members of the elink:VkMemoryPropertyFlagBits
enumeration, which is described below.

* pname:heapIndex is the index into the ptext:memoryHeaps array returned through this
command from which the memory type will be allocated.

The elink:VkMemoryPropertyFlagBits enumeration, which forms the available bits for use in the
pname:propertyFlags member of the slink:VkMemoryType structure is defined as follows:

include::../enums/VkMemoryPropertyFlagBits.txt[]

* ename:VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT signifies that the memory is the
most efficient type for device access (e.g. local device memory).

* ename:VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT indicates that memory with this property is visible
to the host. That is, a valid host address may be obtained and allocations from this memory
type may be mapped.

* ename:VK_MEMORY_PROPERTY_HOST_COHERENT_BIT indicates that accesses to
mapped memory of this type is coherent with accesses to the same memory
by the device. Such access do not need to be marshalled using calls to
flink:vkFlushMappedMemoryRanges or by unmapping the memory.

* ename:VK_MEMORY_PROPERTY_HOST_CACHED_BIT indicates that data stored in
memory of this type is cached by the host and as such, it is likely that
reads from such regions by the host will be faster than reads from uncached
memory.

* ename:VK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT indicates that allocations from this type of memory
may be made on an as-needed basis. In general, allocations from this type of memory will almost
always succeed and return quickly, but first access to such a region may take longer than expected.

The definition of the slink:VkMemoryHeap structure is as follows:

include::../structs/VkMemoryHeap.txt[]

* pname:size specifies the size in bytes of the memory heap.

* pname:flags is a bitfield made up of the members of the
elink:VkMemoryHeapFlagBits enumeration, the definition of which is:

include::../enums/VkMemoryHeapFlagBits.txt[]

* If the ptext:flags member of slink:VkMemoryHeap contains ename:VK_MEMORY_HEAP_HOST_LOCAL_BIT,
then the memory for that heap is located closer to the host than to the device in NUMA (Non-Unified
Memory Architecture) systems. Even in unified architectures, this flag may indicate that access
to this heap is more efficient from the host than from the device.

include::../validity/protos/vkGetPhysicalDeviceMemoryProperties.txt[]

See Also
--------

flink:vkGetPhysicalDeviceProperties

include::footer.txt[]