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EXTENSION(3clc) OpenCL Manual EXTENSION(3clc)

NAME

EXTENSION - A #pragma directive to set the behavior for OpenCL extensions.

#pragma OPENCL EXTENSION extension_name : behavior #pragma OPENCL EXTENSION all : behavior

PARAMETERS

extension_name
The name of the extension. The extension_name will have names of the form cl_khr_<name> for an extension approved by the OpenCL working group and will have names of the form cl_<vendor_name>_<name> for vendor extensions. The token all means that the behavior applies to all extensions supported by the compiler. The table below shows the legal values for extension_name:
Extension name Description
cl_khr_int64_base_atomics(3clc) 64-bit integer base atomic operations
cl_khr_int64_extended_atomics(3clc) 64-bit integer extended atomic operations
cl_khr_3d_image_writes(3clc) Writes to 3D image objects
cl_khr_fp16(3clc) Half-precision floating-point
cl_apple_gl_sharing MacOS X OpenGL sharing
cl_khr_gl_sharing(3clc) OpenGL sharing
cl_khr_gl_event(3clc) CL event objects from GL sync objects
cl_khr_d3d10_sharing(3clc) Sharing memory objects wth Direct3D 10
cl_khr_d3d11_sharing(3clc) Sharing memory objects wth Direct3D 11
cl_khr_dx9_media_sharing(3clc) Sharing memory objects wth Direct3D 9
cl_khr_icd(3clc) Access Khronos OpenCL installable client driver loader (ICD Loader.

behavior

One of the following values:
behavior Description
enable Behave as specified by the extension extension_name. Report an error on the #pragma OPENCL EXTENSION if the extension_name is not supported, or if all is specified. 





  

    disable
    Behave (including issuing errors and warnings) as if the extension
      extension_name is not part of the language definition. If
      all is specified, then behavior must revert back to that of the
      non-extended core version of the language being compiled to. Warn on the
      #pragma OPENCL EXTENSION if the extension extension_name is
      not supported.
  












DESCRIPTION

The #pragma OPENCL EXTENSION directive is a simple, low-level mechanism
  to set the behavior for each extension. It does not define policies such as
  which combinations are appropriate; those must be defined elsewhere. The order
  of directives matter in setting the behavior for each extension. Directives
  that occur later override those seen earlier. The all variant sets the
  behavior for all extensions, overriding all previously issued extension
  directives, but only if the behavior is set to disable.

The initial state of the compiler is as if the directive
    #pragma OPENCL EXTENSION all : disable was issued, telling the
    compiler that all error and warning reporting must be done according to this
    specification, ignoring any extensions.


Every extension which affects the OpenCL language semantics,
    syntax or adds built-in functions to the language must create a preprocessor
    #define that matches the extension name string. This #define would be
    available in the language if and only if the extension is supported on a
    given implementation.






NOTES

This document describes the list of optional features supported by OpenCL 1.2.
  Optional extensions may be supported by some OpenCL devices. Optional
  extensions are not required to be supported by a conformant OpenCL
  implementation, but are expected to be widely available; they define
  functionality that is likely to move into the required feature set in a future
  revision of the OpenCL specification

OpenCL extensions approved by the OpenCL working group can be
    promoted to required core features in later revisions of OpenCL. When this
    occurs, the extension specifications are merged into the core specification.
    Functions and enumerants that are part of such promoted extensions will have
    the KHR affix removed. OpenCL implementations of such later revisions must
    also export the name strings of promoted extensions in the
    CL_PLATFORM_EXTENSIONS or CL_DEVICE_EXTENSIONS string, and
    support the KHR-affixed versions of functions and enumerants as a transition
    aid.




Example

An extension which adds the extension string "cl_khr_3d_image_writes"
  should also add a preprocessor #define called cl_khr_3d_image_writes. A
  kernel can now use this preprocessor #define to do something like the
  following:


  

    #ifdef cl_khr_3d_image_writes // do something using the extension #else
      // do something else or #error! #endif
  












SPECIFICATION

OpenCL Specification[1]





AUTHORS

The Khronos Group





COPYRIGHT

Copyright © 2007-2011 The Khronos Group Inc.


Permission is hereby granted, free of charge, to any person obtaining a copy of
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NOTES



  
 1.

  
OpenCL Specification




page 6, section 9.1 - Compiler Directives for Optional
  Extensions







  

    06/18/2014
    The Khronos Group