Vulkan-Docs/doc/specs/vulkan/chapters/VK_EXT_debug_utils.txt

[[debugging-debug-utils]]
== Debug Utilities

Vulkan provides flexible debugging utilities for debugging an application.

The <<debugging-object-debug-annotation,Object Debug Annotation>> section
describes how to associate either a name or binary data with a specific
Vulkan object.

The <<debugging-queue-labels,Queue Labels>> section describes how to
annotate and group the work submitted to a queue.

The <<debugging-command-buffer-labels,Command Buffer Labels>> section
describes how to associate logical elements of the scene with commands in a
slink:VkCommandBuffer.

The <<debug-messengers,Debug Messengers>> section describes how to create
debug messenger objects associated with an application supplied callback to
capture debug messages from a variety of Vulkan components.

[[debugging-object-debug-annotation]]
=== Object Debug Annotation

It can be useful for an application to provide its own content relative to a
specific Vulkan object.
The following commands allow application developers to associate
user-defined information with Vulkan objects.

[[debugging-object-naming]]
==== Object Naming

An object can be provided a user-defined name by calling
fname:vkSetDebugUtilsObjectNameEXT as defined below.

// refBegin vkSetDebugUtilsObjectNameEXT Give a user-friendly name to an object

include::../api/protos/vkSetDebugUtilsObjectNameEXT.txt[]

  * pname:device is the device that created the object.
  * pname:pNameInfo is a pointer to an instance of the
    slink:VkDebugUtilsObjectNameInfoEXT structure specifying the parameters
    of the name to set on the object.

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

// refEnd vkSetDebugUtilsObjectNameEXT

// refBegin VkDebugUtilsObjectNameInfoEXT Specify parameters of a name to give to an object

The sname:VkDebugUtilsObjectNameInfoEXT structure is defined as:

include::../api/structs/VkDebugUtilsObjectNameInfoEXT.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to an extension-specific structure.
  * pname:objectType is a elink:VkObjectType specifying the type of the
    object to be named.
  * pname:objectHandle is the object to be named.
  * pname:pObjectName is a null-terminated UTF-8 string specifying the name
    to apply to pname:objectHandle.

Applications may: change the name associated with an object simply by
calling fname:vkSetDebugUtilsObjectNameEXT again with a new string.
If pname:pObjectName is an empty string, then any previously set name is
removed.

.Valid Usage
****
  * pname:objectType must: not be ename:VK_OBJECT_TYPE_UNKNOWN
  * pname:objectHandle must: not be dlink:VK_NULL_HANDLE
  * pname:objectHandle must: be a Vulkan object of the type associated with
    pname:objectType as defined in <<debugging-object-types>>.
****

include::../validity/structs/VkDebugUtilsObjectNameInfoEXT.txt[]

// refEnd VkDebugUtilsObjectNameInfoEXT

[[debugging-object-data-association]]
==== Object Data Association

In addition to setting a name for an object, debugging and validation layers
may: have uses for additional binary data on a per-object basis that have no
other place in the Vulkan API.

For example, a sname:VkShaderModule could have additional debugging data
attached to it to aid in offline shader tracing.

Additional data can be attached to an object by calling
fname:vkSetDebugUtilsObjectTagEXT as defined below.

// refBegin vkSetDebugUtilsObjectTagEXT Attach arbitrary data to an object

include::../api/protos/vkSetDebugUtilsObjectTagEXT.txt[]

  * pname:device is the device that created the object.
  * pname:pTagInfo is a pointer to an instance of the
    slink:VkDebugUtilsObjectTagInfoEXT structure specifying the parameters
    of the tag to attach to the object.

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

// refEnd vkSetDebugUtilsObjectTagEXT

// refBegin VkDebugUtilsObjectTagInfoEXT Specify parameters of a tag to attach to an object

The sname:VkDebugUtilsObjectTagInfoEXT structure is defined as:

include::../api/structs/VkDebugUtilsObjectTagInfoEXT.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to an extension-specific structure.
  * pname:objectType is a elink:VkObjectType specifying the type of the
    object to be named.
  * pname:objectHandle is the object to be tagged.
  * pname:tagName is a numerical identifier of the tag.
  * pname:tagSize is the number of bytes of data to attach to the object.
  * pname:pTag is an array of pname:tagSize bytes containing the data to be
    associated with the object.

The pname:tagName parameter gives a name or identifier to the type of data
being tagged.
This can be used by debugging layers to easily filter for only data that can
be used by that implementation.

.Valid Usage
****
  * pname:objectType must: not be ename:VK_OBJECT_TYPE_UNKNOWN
  * pname:objectHandle must: not be dlink:VK_NULL_HANDLE
  * pname:objectHandle must: be a Vulkan object of the type associated with
    pname:objectType as defined in <<debugging-object-types>>.
****

include::../validity/structs/VkDebugUtilsObjectTagInfoEXT.txt[]

// refEnd VkDebugUtilsObjectTagInfoEXT


[[debugging-queue-labels]]
=== Queue Labels

All Vulkan work must be submitted using queues.
It is possible for an application to use multiple queues, each containing
multiple command buffers, when performing work.
It can be useful to identify which queue, or even where in a queue,
something has occurred.

To begin identifying a region using a debug label inside a queue, you may
use the flink:vkQueueBeginDebugUtilsLabelEXT command.

Then, when the region of interest has passed, you may end the label region
using flink:vkQueueEndDebugUtilsLabelEXT.

Additionally, a single debug label may be inserted at any time using
flink:vkQueueInsertDebugUtilsLabelEXT.

// refBegin vkQueueBeginDebugUtilsLabelEXT Open a queue debug label region

A queue debug label region is opened by calling:

include::../api/protos/vkQueueBeginDebugUtilsLabelEXT.txt[]

  * pname:queue is the queue in which to start a debug label region.
  * pname:pLabelInfo is a pointer to an instance of the
    slink:VkDebugUtilsLabelEXT structure specifying the parameters of the
    label region to open.

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

// refEnd vkQueueBeginDebugUtilsLabelEXT

// refBegin VkDebugUtilsLabelEXT Specify parameters of a label region

The sname:VkDebugUtilsLabelEXT structure is defined as:

include::../api/structs/VkDebugUtilsLabelEXT.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to an extension-specific structure.
  * pname:pLabelName is a pointer to a null-terminated UTF-8 string that
    contains the name of the label.
  * pname:color is an optional RGBA color value that can be associated with
    the label.
    A particular implementation may: choose to ignore this color value.
    The values contain RGBA values in order, in the range 0.0 to 1.0.
    If all elements in pname:color are set to 0.0 then it is ignored.

include::../validity/structs/VkDebugUtilsLabelEXT.txt[]

// refEnd VkDebugUtilsLabelEXT

// refBegin vkQueueEndDebugUtilsLabelEXT Close a queue debug label region

A queue debug label region is closed by calling:

include::../api/protos/vkQueueEndDebugUtilsLabelEXT.txt[]

  * pname:queue is the queue in which a debug label region should be closed.

The calls to flink:vkQueueBeginDebugUtilsLabelEXT and
flink:vkQueueEndDebugUtilsLabelEXT must: be matched and balanced.

.Valid Usage
****
  * There must: be an outstanding fname:vkQueueBeginDebugUtilsLabelEXT
    command prior to the fname:vkQueueEndDebugUtilsLabelEXT on the queue
****

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

// refEnd vkQueueEndDebugUtilsLabelEXT

// refBegin vkQueueInsertDebugUtilsLabelEXT Insert a label into a queue

A single label can be inserted into a queue by calling:

include::../api/protos/vkQueueInsertDebugUtilsLabelEXT.txt[]

  * pname:queue is the queue into which a debug label will be inserted.
  * pname:pLabelInfo is a pointer to an instance of the
    slink:VkDebugUtilsLabelEXT structure specifying the parameters of the
    label to insert.

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

// refEnd vkQueueInsertDebugUtilsLabelEXT


[[debugging-command-buffer-labels]]
=== Command Buffer Labels

Typical Vulkan applications will submit many command buffers in each frame,
with each command buffer containing a large number of individual commands.
Being able to logically annotate regions of command buffers that belong
together as well as hierarchically subdivide the frame is important to a
developer's ability to navigate the commands viewed holistically.

To identify the beginning of a debug label region in a command buffer,
flink:vkCmdBeginDebugUtilsLabelEXT can: be used as defined below.

To indicate the end of a debug label region in a command buffer,
flink:vkCmdEndDebugUtilsLabelEXT can: be used.

To insert a single command buffer debug label inside of a command buffer,
flink:vkCmdInsertDebugUtilsLabelEXT can: be used as defined below.

// refBegin vkCmdBeginDebugUtilsLabelEXT Open a command buffer debug label region

A command buffer debug label region can be opened by calling:

include::../api/protos/vkCmdBeginDebugUtilsLabelEXT.txt[]

  * pname:commandBuffer is the command buffer into which the command is
    recorded.
  * pname:pLabelInfo is a pointer to an instance of the
    slink:VkDebugUtilsLabelEXT structure specifying the parameters of the
    label region to open.

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

// refEnd vkCmdBeginDebugUtilsLabelEXT

// refBegin vkCmdEndDebugUtilsLabelEXT Close a command buffer label region

A command buffer label region can be closed by calling:

include::../api/protos/vkCmdEndDebugUtilsLabelEXT.txt[]

  * pname:commandBuffer is the command buffer into which the command is
    recorded.

An application may: open a debug label region in one command buffer and
close it in another, or otherwise split debug label regions across multiple
command buffers or multiple queue submissions.
When viewed from the linear series of submissions to a single queue, the
calls to flink:vkCmdBeginDebugUtilsLabelEXT and
flink:vkCmdEndDebugUtilsLabelEXT must: be matched and balanced.

.Valid Usage
****
  * There must: be an outstanding fname:vkCmdBeginDebugUtilsLabelEXT command
    prior to the fname:vkCmdEndDebugUtilsLabelEXT on the queue that
    pname:commandBuffer is submitted to
  * If pname:commandBuffer is a secondary command buffer, there must: be an
    outstanding fname:vkCmdBeginDebugUtilsLabelEXT command recorded to
    pname:commandBuffer that has not previously been ended by a call to
    fname:vkCmdEndDebugUtilsLabelEXT.
****

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

// refEnd vkCmdEndDebugUtilsLabelEXT

// refBegin vkCmdInsertDebugUtilsLabelEXT Insert a label into a command buffer

A single debug label can be inserted into a command buffer by calling:

include::../api/protos/vkCmdInsertDebugUtilsLabelEXT.txt[]

  * pname:commandBuffer is the command buffer into which the command is
    recorded.
  * pname:pInfo is a pointer to an instance of the
    slink:VkDebugUtilsLabelEXT structure specifying the parameters of the
    label to insert.

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

// refEnd vkCmdInsertDebugUtilsLabelEXT


[[debugging-debug-messengers]]
=== Debug Messengers

Vulkan allows an application to register multiple callbacks with any Vulkan
component wishing to report debug information.
Some callbacks may log the information to a file, others may cause a debug
break point or other application defined behavior.
A primary producer of callback messages are the validation layers.
An application can: register callbacks even when no validation layers are
enabled, but they will only be called for the Vulkan loader and, if
implemented, other layer and driver events.

// refBegin VkDebugUtilsMessengerEXT Opaque handle to a debug messenger object

A sname:VkDebugUtilsMessengerEXT is a messenger object which handles passing
along debug messages to a provided debug callback.

include::../api/handles/VkDebugUtilsMessengerEXT.txt[]

The debug messenger will provide detailed feedback on the application's use
of Vulkan when events of interest occur.
When an event of interest does occur, the debug messenger will submit a
debug message to the debug callback that was provided during its creation.
Additionally, the debug messenger is responsible with filtering out debug
messages that the callback isn't interested in and will only provide desired
debug messages.

// refEnd VkDebugUtilsMessengerEXT

// refBegin vkCreateDebugUtilsMessengerEXT Create a debug messenger object

A debug messenger triggers a debug callback with a debug message when an
event of interest occurs.
To create a debug messenger which will trigger a debug callback, call:

include::../api/protos/vkCreateDebugUtilsMessengerEXT.txt[]

  * pname:instance the instance the messenger will be used with.
  * pname:pCreateInfo points to a slink:VkDebugUtilsMessengerCreateInfoEXT
    structure which contains the callback pointer as well as defines the
    conditions under which this messenger will trigger the callback.
  * pname:pAllocator controls host memory allocation as described in the
    <<memory-allocation, Memory Allocation>> chapter.
  * pname:pMessenger is a pointer to record the
    sname:VkDebugUtilsMessengerEXT object created.

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

// refEnd VkDebugUtilsMessengerEXT

// refBegin VkDebugUtilsMessengerCreateInfoEXT Structure specifying parameters of a newly created debug messenger

The definition of sname:VkDebugUtilsMessengerCreateInfoEXT is:

include::../api/structs/VkDebugUtilsMessengerCreateInfoEXT.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to an extension-specific structure.
  * pname:flags is 0 and reserved for future use.
  * pname:messageSeverity is a bitmask of
    elink:VkDebugUtilsMessageSeverityFlagBitsEXT specifying which severity
    of event(s) will cause this callback to be called.
  * pname:messageTypes is a bitmask of
    elink:VkDebugUtilsMessageTypeFlagBitsEXT specifying which type of
    event(s) will cause this callback to be called.
  * pname:pfnUserCallback is the application callback function to call.
  * pname:pUserData is user data to be passed to the callback.

For each sname:VkDebugUtilsMessengerEXT that is created the
sname:VkDebugUtilsMessengerCreateInfoEXT::pname:messageSeverity and
sname:VkDebugUtilsMessengerCreateInfoEXT::pname:messageTypes determine when
that sname:VkDebugUtilsMessengerCreateInfoEXT::pname:pfnUserCallback is
called.
The process to determine if the user's pfnUserCallback is triggered when an
event occurs is as follows:

 . The implementation will perform a bitwise AND of the event's
   elink:VkDebugUtilsMessageSeverityFlagBitsEXT with the
   pname:messageSeverity provided during creation of the
   slink:VkDebugUtilsMessengerEXT object.
 .. If the value is 0, the message is skipped.
 . The implementation will perform bitwise AND of the event's
   elink:VkDebugUtilsMessageTypeFlagBitsEXT with the pname:messageType
   provided during the creation of the slink:VkDebugUtilsMessengerEXT
   object.
 .. If the value is 0, the message is skipped.
 . The callback will trigger a debug message for the current event

The callback will come directly from the component that detected the event,
unless some other layer intercepts the calls for its own purposes (filter
them in a different way, log to a system error log, etc.).

An application can: receive multiple callbacks if multiple
sname:VkDebugUtilsMessengerEXT objects are created.
A callback will always be executed in the same thread as the originating
Vulkan call.

A callback can: be called from multiple threads simultaneously (if the
application is making Vulkan calls from multiple threads).

.Valid Usage
****
  * pname:pfnUserCallback must: be a valid
    tlink:PFN_vkDebugUtilsMessengerCallbackEXT
****

include::../validity/structs/VkDebugUtilsMessengerCreateInfoEXT.txt[]

// refEnd VkDebugUtilsMessengerCreateInfoEXT

// refBegin VkDebugUtilsMessageSeverityFlagBitsEXT Bitmask specifying which severities of events cause a debug messenger callback

Bits which can: be set in
slink:VkDebugUtilsMessengerCreateInfoEXT::pname:messageSeverity, specifying
event severities which cause a debug messenger to call the callback, are:

include::../api/enums/VkDebugUtilsMessageSeverityFlagBitsEXT.txt[]

  * ename:VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXT specifies the most
    verbose output indicating all diagnostic messages from the Vulkan
    loader, layers, and drivers should be captured.
  * ename:VK_DEBUG_UTILS_MESSAGE_SEVERITY_INFO_BIT_EXT specifies an
    informational message such as resource details that may be handy when
    debugging an application.
  * ename:VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT specifies use of
    Vulkan that may: expose an app bug.
    Such cases may not be immediately harmful, such as a fragment shader
    outputting to a location with no attachment.
    Other cases may: point to behavior that is almost certainly bad when
    unintended such as using an image whose memory has not been filled.
    In general if you see a warning but you know that the behavior is
    intended/desired, then simply ignore the warning.
  * ename:VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT specifies that an
    error that may cause undefined results, including an application crash.

// refEnd VkDebugUtilsMessageSeverityFlagBitsEXT

[NOTE]
.Note
====
The values of ename:VkDebugUtilsMessageSeverityFlagBitsEXT are sorted based
on severity.
The higher the flag value, the more severe the message.
This allows for simple boolean operation comparisons when looking at
ename:VkDebugUtilsMessageSeverityFlagBitsEXT values.

For example:

[source,c++]
----------------------------------------
    if (messageSeverity >= VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT) {
        // Do something for warnings and errors
    }
----------------------------------------

In addition, space has been left between the enums to allow for later
addition of new severities in between the existing values.
====

// refBegin VkDebugUtilsMessageTypeFlagBitsEXT Bitmask specifying which types of events cause a debug messenger callback

Bits which can: be set in
slink:VkDebugUtilsMessengerCreateInfoEXT::pname:messageTypes, specifying
event types which cause a debug messenger to call the callback, are:

include::../api/enums/VkDebugUtilsMessageTypeFlagBitsEXT.txt[]

  * ename:VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT specifies that some
    general event has occurred.
    This is typically a non-specification, non-performance event.
  * ename:VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT specifies that
    something has occurred during validation against the Vulkan
    specification that may indicate invalid behavior.
  * ename:VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT specifies a
    potentially non-optimal use of Vulkan, e.g. using
    flink:vkCmdClearColorImage when setting
    slink:VkAttachmentDescription::pname:loadOp to
    ename:VK_ATTACHMENT_LOAD_OP_CLEAR would have worked.

// refEnd VkDebugUtilsMessageTypeFlagBitsEXT

// refBegin PFN_vkDebugUtilsMessengerCallbackEXT Application-defined debug messenger callback function

The prototype for the
slink:VkDebugUtilsMessengerCreateInfoEXT::pname:pfnUserCallback function
implemented by the application is:

include::../api/funcpointers/PFN_vkDebugUtilsMessengerCallbackEXT.txt[]

  * pname:messageSeverity indicates the
    elink:VkDebugUtilsMessageSeverityFlagBitsEXT that triggered this
    callback.
  * pname:messageTypes indicates the
    elink:VkDebugUtilsMessageTypeFlagBitsEXT that triggered this callback.
  * pname:pCallbackData contains all the callback related data in the
    slink:VkDebugUtilsMessengerCallbackDataEXT structure.
  * pname:pUserData is the user data provided when the
    slink:VkDebugUtilsMessengerEXT was created.

The callback must: not call flink:vkDestroyDebugUtilsMessengerEXT.

The callback returns a basetype:VkBool32, which is interpreted in a
layer-specified manner.
The application should: always return ename:VK_FALSE.
The ename:VK_TRUE value is reserved for use in layer development.

// refEnd PFN_vkDebugUtilsMessengerCallbackEXT

// refBegin VkDebugUtilsMessengerCallbackDataEXT Structure specifying parameters returned to the callback

The definition of sname:VkDebugUtilsMessengerCallbackDataEXT is:

include::../api/structs/VkDebugUtilsMessengerCallbackDataEXT.txt[]

  * pname:sType is the type of this structure.
  * pname:pNext is `NULL` or a pointer to an extension-specific structure.
  * pname:flags is 0 and reserved for future use.
  * pname:pMessageIdName is a null-terminated string that identifies the the
    particular message ID that is associated with the provided message.
    If the message corresponds to a validation layer message, then this
    string may contain the portion of the Vulkan specification that is
    believed to have been violated.
  * pname:messageIdNumber is the ID number of the triggering message.
    If the message corresponds to a validation layer message, then this
    number is related to the internal number associated with the message
    being triggered.
  * pname:pMessage is a null-terminated string detailing the trigger
    conditions.
  * pname:queueLabelCount is a count of items contained in the
    pname:pQueueLabels array.
  * pname:pQueueLabels is NULL or a pointer to an array of
    slink:VkDebugUtilsLabelEXT active in the current sname:VkQueue at the
    time the callback was triggered.
    Refer to <<debugging-queue-labels,Queue Labels>> for more information.
  * pname:cmdBufLabelCount is a count of items contained in the
    pname:pCmdBufLabels array.
  * pname:pCmdBufLabels is NULL or a pointer to an array of
    slink:VkDebugUtilsLabelEXT active in the current sname:VkCommandBuffer
    at the time the callback was triggered.
    Refer to <<debugging-command-buffer-labels, Command Buffer Labels>> for
    more information.
  * pname:objectCount is a count of items contained in the pname:pObjects
    array.
  * pname:pObjects is a pointer to an array of
    slink:VkDebugUtilsObjectNameInfoEXT objects related to the detected
    issue.
    The array is roughly in order or importance, but the 0th element is
    always guaranteed to be the most important object for this message.

[NOTE]
.Note
====
This structure should only be considered valid during the lifetime of the
triggered callback.
====

Since adding queue and command buffer labels behaves like pushing and
popping onto a stack, the order of both pname:pQueueLabels and
pname:pCmdBufLabels is based on the order the labels were defined.
The result is that the first label in either pname:pQueueLabels or
pname:pCmdBufLabels will be the first defined (and therefore the oldest)
while the last label in each list will be the most recent.

[NOTE]
.Note
====
pname:pQueueLabels will only be non-NULL if one of the objects in
pname:pObjects can be related directly to a defined sname:VkQueue which has
had one or more labels associated with it.

Likewise, pname:pCmdBufLabels will only be non-NULL if one of the objects in
pname:pObjects can be related directly to a defined sname:VkCommandBuffer
which has had one or more labels associated with it.
Additionally, while command buffer labels allow for beginning and ending
across different command buffers, the debug messaging framework cannot:
guarantee that labels in pname:pCmdBufLables will contain those defined
outside of the associated command buffer.
This is partially due to the fact that the association of one command buffer
with another may not have been defined at the time the debug message is
triggered.
====

include::../validity/structs/VkDebugUtilsMessengerCallbackDataEXT.txt[]

// refEnd VkDebugUtilsMessengerCallbackDataEXT

// refBegin vkSubmitDebugUtilsMessageEXT Inject a message into a debug stream

There may be times that a user wishes to intentionally submit a debug
message.
To do this, call:

include::../api/protos/vkSubmitDebugUtilsMessageEXT.txt[]

  * pname:instance is the debug stream's sname:VkInstance.
  * pname:messageSeverity is the
    elink:VkDebugUtilsMessageSeverityFlagBitsEXT severity of this
    event/message.
  * pname:messageTypes is a bitmask of
    elink:VkDebugUtilsMessageTypeFlagBitsEXT specifying which type of
    event(s) to identify with this message.
  * pname:pCallbackData contains all the callback related data in the
    slink:VkDebugUtilsMessengerCallbackDataEXT structure.

The call will propagate through the layers and generate callback(s) as
indicated by the message's flags.
The parameters are passed on to the callback in addition to the
pname:pUserData value that was defined at the time the messenger was
registered.

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

// refEnd vkSubmitDebugUtilsMessageEXT

// refBegin vkDestroyDebugUtilsMessengerEXT Destroy a debug messenger object

To destroy a sname:VkDebugUtilsMessengerEXT object, call:

include::../api/protos/vkDestroyDebugUtilsMessengerEXT.txt[]

 * pname:instance the instance where the callback was created.
 * pname:messenger the sname:VkDebugUtilsMessengerEXT object to destroy.
   pname:messenger is an externally synchronized object and must: not be
   used on more than one thread at a time.
   This means that fname:vkDestroyDebugUtilsMessengerEXT must: not be called
   when a callback is active.
 * pname:pAllocator controls host memory allocation as described in the
   <<memory-allocation, Memory Allocation>> chapter.

.Valid Usage
****
  * If sname:VkAllocationCallbacks were provided when pname:messenger was
    created, a compatible set of callbacks must: be provided here
  * If no sname:VkAllocationCallbacks were provided when pname:messenger was
    created, pname:pAllocator must: be `NULL`
****

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

// refEnd vkDestroyDebugUtilsMessengerEXT