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