VKGETINSTANCEPROCADD(3)

NAME
vkGetInstanceProcAddr - Return a function pointer for a command

C SPECIFICATION

Vulkan commands are not necessarily exposed statically on a platform. Function pointers for all Vulkan commands can be obtained with the command:

    PFN_vkVoidFunction vkGetInstanceProcAddr(
        VkInstance                                  instance,
        const char*                                 pName);

PARAMETERS

    • instance is the instance that the function pointer will be compatible with, or NULL for commands not dependent on any instance.

    • pName is the name of the command to obtain.

DESCRIPTION

vkGetInstanceProcAddr itself is obtained in a platform- and loader- specific manner. Typically, the loader library will export this command as a function symbol, so applications can link against the loader library, or load it dynamically and look up the symbol using platform-specific APIs. Loaders are encouraged to export function symbols for all other core Vulkan commands as well; if this is done, then applications that use only the core Vulkan commands have no need to use vkGetInstanceProcAddr.

The table below defines the various use cases for vkGetInstanceProcAddr and expected return value ("fp" is function pointer) for each case.

The returned function pointer is of type PFN_vkVoidFunction, and must be cast to the type of the command being queried.

Table 1. vkGetInstanceProcAddr behavior
instance | pName | return value
* | NULL | undefined
invalid instance | * | undefined
NULL | vkEnumerateInstanceExtensionProperties | fp
NULL | vkEnumerateInstanceLayerProperties | fp
NULL | vkCreateInstance | fp
NULL | * (any pName not covered above) | NULL
instance | core Vulkan command | fp1
instance | enabled instance extension commands for instance | fp1
instance | available device extension2 commands for instance | fp1
instance | * (any pName not covered above) | NULL

1
    The returned function pointer must only be called with a dispatchable object (the first parameter) that is instance or a child of instance. e.g. VkInstance, VkPhysicalDevice, VkDevice, VkQueue, or VkCommandBuffer.

2
    An “available extension” is an extension function supported by any of the loader, driver or layer.
Valid Usage (Implicit)

    • If instance is not NULL, instance must be a valid VkInstance handle

    • pName must be a null-terminated string

SEE ALSO

PFN_vkVoidFunction, VkInstance

DOCUMENT NOTES

For more information, see the Vulkan Specification at URL

https://www.khronos.org/registry/vulkan/specs/1.0/xhtml/vkspec.html#vkGetInstanceProcAddr

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification,not directly.

COPYRIGHT

Copyright (c) 2014-2016 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.

AUTHOR

Khronos Group
    Author.