Copyright © 2015-2020 LunarG, Inc.

Creative Commons


The VK_LAYER_LUNARG_api_dump utility layer prints API calls, parameters, and values to the identified output stream. It has several settings that can be adjusted by either environment variables or by using the vk_layer_settings.txt file.

Enabling the Layer


The API dump layer can be enabled using vkconfig. See the vkconfig documentation for more information.

Desktop (Linux/Windows/MacOS)

You must add the location of the generated VK_LAYER_LUNARG_api.json file and corresponding VkLayer_api_dump library to your VK_LAYER_PATH in order for the Vulkan loader to be able to find the layer.

Then, you must also enable the layer in one of two ways:

Setting the VK_LAYER_PATH


If your source was located in: C:\my_folder\vulkantools and your build folder was build64, then you would add it to the layer path in the following way:

set VK_LAYER_PATH=C:\my_folder\vulkantools\build64\layersvt\Debug;%VK_LAYER_PATH%


If your source was located in: /my_folder/vulkantools and your build folder was build, then you would add it to the layer path in the following way:

export VK_LAYER_PATH=/my_folder/vulkantools/build/layersvt:$VK_LAYER_PATH

Forcing the layer with VK_INSTANCE_LAYERS

To force the layer to be enabled for Vulkan applications, you can set the VK_INSTANCE_LAYERS environment variable in the following way:







You may need to grant permissions to your application to write to system storage, even if it normally does not. This depends on whether or not you modify API Dump to output to a file or just leave it to output to text.

If you're building with Android Studio, you do this by:

If this does not work, you may still require enabling permissions for your application from the settings menu.

Failure to do so will result in your application crashing during vkCreateInstance since the layer will attempt, but fail, to create the capture file.

Globally Enabling the Layer

Use ADB to enable the layer for your project by:

adb shell "setprop debug.vulkan.layers 'VK_LAYER_LUNARG_api_dump'"

When done, disable the layer using:

adb shell "setprop debug.vulkan.layers ''"

API Dump Options

Setting Environment Variable Settings File Value Default Description
Enable File Output None: Implicitly defined when filename defined lunarg_api_dump.file Not Set Force output of API Dump layer to be written to a file instead of stdout.
Output File Name VK_APIDUMP_LOG_FILENAME lunarg_api_dump.log_filename stdout The name (and path) of the output file to save the generated content to.
Detailed Output VK_APIDUMP_DETAILED lunarg_api_dump.detailed true Generate more detailed output of the commands including parameters and values. If false only output function signature.
No Addresses/Handles VK_APIDUMP_NO_ADDR lunarg_api_dump.no_addr false Generate output without addresses or handles (which can vary run to run. Instead use the placeholder value "address".
Flush After Every Command VK_APIDUMP_FLUSH lunarg_api_dump.flush true Flush after every API command's output
Output format VK_APIDUMP_OUTPUT_FORMAT lunarg_api_dump.output_format text Output the API Dump information as a text file (text), an HTML-formated file (html), or a json file (json).
Selective Output Range VK_APIDUMP_OUTPUT_RANGE lunarg_api_dump.output_range 0-0 Only output frames within the specified range. Given by a comma separated list of frames or a range with a start, count, and optional interval separated by dashes. A count of 0 will output every frame after the start of the range. Example: "5-8-2" will output frame 5, continue until frame 13, dumping every other frame. Example: "3,8-2" will output frames 3, 8, and 9.
Show Timestamps VK_APIDUMP_TIMESTAMP lunarg_api_dump.show_timestamp false Show the timestamp of function calls since start in microseconds

Settings Priority

If you have a setting defined in both the Settings File as well as an Environment Variable, the Environment Variable value will always override the Settings File value. This is intended to let you dynamically change settings without having to adjust the Settings File.

Applying Environment Settings on Android

On Android, you must use properties to set the environment variables. The format of the properties to set takes the following form:

debug. + (lower-case environment variable with 'vk_' stripped)

The easiest way to set a property is from the ADB shell:

adb shell "setprop <property_name> '<property_value>'"

For example:

To set the API Dump output log filename, which on desktop uses VK_APIDUMP_LOG_FILENAME set the following property:


Which you can set in the following way:

adb shell "setprop debug.apidump_log_filename '/sdcard/Android/vk_apidump.txt'"

Settings File Specific Settings

At this time, certain settings are only available to be set in the vk_layer_settings.txt file. These are:

Setting Settings File Value Default Description
Indent Size lunarg_api_dump.indent_size 4 Set the indent size for writing out parameters and values for each command. Only valid for text format and stdout writing.
Name Size lunarg_api_dump.name_size 32 Set the max length to assume for written names. This is intended to allow cleaner indenting by reserving space for names shorter than this length. A value of 0 means no additional spacing applied. Only valid when "Use Spaces" is enabled.
Show Shader lunarg_api_dump.show_shader false Output the contents of any shader file loaded.
Show Types lunarg_api_dump.show_types true Output the types for each setting.
Type Size lunarg_api_dump.type_size 0 Set the max length to assume for written types. This is intended to allow cleaner indenting by reserving space for types shorter than this length. A value of 0 means no additional spacing applied. Only valid when "Use Spaces" is enabled.
Use Spaces lunarg_api_dump.use_spaces true Attempt to use additional white space to produce a cleaner/easier-to-read output.
Show Thread And Frame lunarg_api_dump.show_thread_and_frame true Show the thread and frame of each function called.