NAME

       clGetExtensionFunctionAddressForPlatform - Returns the address of the extension function named by
       funcname for a given platform.

       void* clGetExtensionFunctionAddressForPlatform(cl_platform_id platform, const char *funcname);

PARAMETERS

        funcname
           Name of an extension function.

DESCRIPTION

       The function clGetExtensionFunctionAddressForPlatform returns the address of the extension function named
       by funcname for a given platform. The pointer returned should be cast to a function pointer type matching
       the extension function's definition defined in the appropriate extension specification and header file.

       A return value of NULL indicates that the specified function does not exist for the implementation or
       platform is not a valid platform. A non-NULL return value for clGetExtensionFunctionAddressForPlatform
       does not guarantee that an extension function is actually supported by the platform. The application must
       also make a corresponding query using clGetPlatformInfo(3clc) (platform, CL_PLATFORM_EXTENSIONS, ... ) or
       clGetDeviceInfo(3clc) (device,CL_DEVICE_EXTENSIONS, ... ) to determine if an extension is supported by
       the OpenCL implementation.

       clGetExtensionFunctionAddressForPlatform may not be queried for core (non-extension) functions in OpenCL.
       For functions that are queryable with clGetExtensionFunctionAddressForPlatform, implementations may
       choose to also export those functions statically from the object libraries implementing those functions.
       However, portable applications cannot rely on this behavior.

       Function pointer typedefs must be declared for all extensions that add API entrypoints. These typedefs
       are a required part of the extension interface, to be provided in an appropriate header (such as cl_ext.h
       if the extension is an OpenCL extension, or cl_gl_ext.h if the extension is an OpenCL/OpenGL sharing
       extension).

NOTES

       Since there is no way to qualify the query with a device, the function pointer returned must work for all
       implementations of that extension on different devices for a platform. The behavior of calling a device
       extension function on a device not supporting that extension is undefined.

   Example
       The following convention must be followed for all extensions affecting the host API, where TAG can be
       KHR, EXT or vendor-specific:

       #ifndef extension_name #define extension_name       1

       // all data typedefs, token #defines, prototypes, and //
       function pointer typedefs for this extension

       // function pointer typedefs must use the // following
       naming convention typedef CL_API_ENTRY return type
       (CL_API_CALL *clextension_func_nameTAG_fn)(...);

       #endif // extension_name

       Consider, for example, the cl_khr_gl_sharing(3clc) extension. This extension would add the following to
       cl_gl_ext.h::

       #ifndef cl_khr_gl_sharing #define cl_khr_gl_sharing
       1

       // all data typedefs, token #defines, prototypes, and //
       function pointer typedefs for this extension #define
       CL_INVALID_GL_SHAREGROUP_REFERENCE_KHR -1000 #define
       CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KHR   0x2006 #define
       CL_DEVICES_FOR_GL_CONTEXT_KHR          0x2007 #define
       CL_GL_CONTEXT_KHR                      0x2008 #define
       CL_EGL_DISPLAY_KHR                     0x2009 #define
       CL_GLX_DISPLAY_KHR                     0x200A #define
       CL_WGL_HDC_KHR                         0x200B #define
       CL_CGL_SHAREGROUP_KHR                  0x200C

       // function pointer typedefs must use the // following
       naming convention typedef CL_API_ENTRY cl_int
       (CL_API_CALL *clGetGLContextInfoKHR_fn)( const
       cl_context_properties * /* properties */,
       cl_gl_context_info /* param_name */, size_t /*
       param_value_size */, void * /* param_value */, size_t *
       /*param_value_size_ret*/); #endif // cl_khr_gl_sharing

SPECIFICATION

       OpenCL Specification[1]

SEE ALSO

       EXTENSION(3clc)

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 this software and/or
       associated documentation files (the "Materials"), to deal in the Materials without restriction, including
       without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
       copies of the Materials, and to permit persons to whom the Materials are furnished to do so, subject to
       the condition that this copyright notice and permission notice shall be included in all copies or
       substantial portions of the Materials.

NOTES

        1. OpenCL Specification
           page 7, section 9.2 - Getting OpenCL API Extension Function Pointers