Quelle  clew.c   Sprache: C

//////////////////////////////////////////////////////////////////////////
//  Copyright (c) 2009-2011 Organic Vectory B.V.
//  Written by George van Venrooij
//
//  Distributed under the Boost Software License, Version 1.0.
//  (See accompanying file license.txt)
//////////////////////////////////////////////////////////////////////////

#include "clew/clew.h"

//! \file clew.c
//! \brief OpenCL run-time loader source

#ifndef CLCC_GENERATE_DOCUMENTATION
    #ifdef _WIN32
        #define WIN32_LEAN_AND_MEAN
        #include <windows.h>

        typedef HMODULE             CLCC_DYNLIB_HANDLE;

        #define CLCC_DYNLIB_OPEN    LoadLibrary
        #define CLCC_DYNLIB_CLOSE   FreeLibrary
        #define CLCC_DYNLIB_IMPORT  GetProcAddress
    #else
        #include <dlfcn.h>

        typedef void*                   CLCC_DYNLIB_HANDLE;

        #define CLCC_DYNLIB_OPEN(path)  dlopen(path, RTLD_NOW | RTLD_GLOBAL)
        #define CLCC_DYNLIB_CLOSE       dlclose
        #define CLCC_DYNLIB_IMPORT      dlsym
    #endif
#else
    //typedef implementation_defined  CLCC_DYNLIB_HANDLE;
    //#define CLCC_DYNLIB_OPEN(path)  implementation_defined
    //#define CLCC_DYNLIB_CLOSE       implementation_defined
    //#define CLCC_DYNLIB_IMPORT      implementation_defined
#endif

#include <stdlib.h>

//! \brief module handle
static CLCC_DYNLIB_HANDLE module = NULL;

//  Variables holding function entry points
#ifndef CLCC_GENERATE_DOCUMENTATION
PFNCLGETPLATFORMIDS                 __clewGetPlatformIDs                = NULL;
PFNCLGETPLATFORMINFO                __clewGetPlatformInfo               = NULL;
PFNCLGETDEVICEIDS                   __clewGetDeviceIDs                  = NULL;
PFNCLGETDEVICEINFO                  __clewGetDeviceInfo                 = NULL;
PFNCLCREATECONTEXT                  __clewCreateContext                 = NULL;
PFNCLCREATECONTEXTFROMTYPE          __clewCreateContextFromType         = NULL;
PFNCLRETAINCONTEXT                  __clewRetainContext                 = NULL;
PFNCLRELEASECONTEXT                 __clewReleaseContext                = NULL;
PFNCLGETCONTEXTINFO                 __clewGetContextInfo                = NULL;
PFNCLCREATECOMMANDQUEUE             __clewCreateCommandQueue            = NULL;
PFNCLRETAINCOMMANDQUEUE             __clewRetainCommandQueue            = NULL;
PFNCLRELEASECOMMANDQUEUE            __clewReleaseCommandQueue           = NULL;
PFNCLGETCOMMANDQUEUEINFO            __clewGetCommandQueueInfo           = NULL;
PFNCLSETCOMMANDQUEUEPROPERTY        __clewSetCommandQueueProperty       = NULL;
PFNCLCREATEBUFFER                   __clewCreateBuffer                  = NULL;
PFNCLCREATEIMAGE2D                  __clewCreateImage2D                 = NULL;
PFNCLCREATEIMAGE3D                  __clewCreateImage3D                 = NULL;
PFNCLRETAINMEMOBJECT                __clewRetainMemObject               = NULL;
PFNCLRELEASEMEMOBJECT               __clewReleaseMemObject              = NULL;
PFNCLGETSUPPORTEDIMAGEFORMATS       __clewGetSupportedImageFormats      = NULL;
PFNCLGETMEMOBJECTINFO               __clewGetMemObjectInfo              = NULL;
PFNCLGETIMAGEINFO                   __clewGetImageInfo                  = NULL;
PFNCLCREATESAMPLER                  __clewCreateSampler                 = NULL;
PFNCLRETAINSAMPLER                  __clewRetainSampler                 = NULL;
PFNCLRELEASESAMPLER                 __clewReleaseSampler                = NULL;
PFNCLGETSAMPLERINFO                 __clewGetSamplerInfo                = NULL;
PFNCLCREATEPROGRAMWITHSOURCE        __clewCreateProgramWithSource       = NULL;
PFNCLCREATEPROGRAMWITHBINARY        __clewCreateProgramWithBinary       = NULL;
PFNCLRETAINPROGRAM                  __clewRetainProgram                 = NULL;
PFNCLRELEASEPROGRAM                 __clewReleaseProgram                = NULL;
PFNCLBUILDPROGRAM                   __clewBuildProgram                  = NULL;
PFNCLUNLOADCOMPILER                 __clewUnloadCompiler                = NULL;
PFNCLGETPROGRAMINFO                 __clewGetProgramInfo                = NULL;
PFNCLGETPROGRAMBUILDINFO            __clewGetProgramBuildInfo           = NULL;
PFNCLCREATEKERNEL                   __clewCreateKernel                  = NULL;
PFNCLCREATEKERNELSINPROGRAM         __clewCreateKernelsInProgram        = NULL;
PFNCLRETAINKERNEL                   __clewRetainKernel                  = NULL;
PFNCLRELEASEKERNEL                  __clewReleaseKernel                 = NULL;
PFNCLSETKERNELARG                   __clewSetKernelArg                  = NULL;
PFNCLGETKERNELINFO                  __clewGetKernelInfo                 = NULL;
PFNCLGETKERNELWORKGROUPINFO         __clewGetKernelWorkGroupInfo        = NULL;
PFNCLWAITFOREVENTS                  __clewWaitForEvents                 = NULL;
PFNCLGETEVENTINFO                   __clewGetEventInfo                  = NULL;
PFNCLRETAINEVENT                    __clewRetainEvent                   = NULL;
PFNCLRELEASEEVENT                   __clewReleaseEvent                  = NULL;
PFNCLGETEVENTPROFILINGINFO          __clewGetEventProfilingInfo         = NULL;
PFNCLFLUSH                          __clewFlush                         = NULL;
PFNCLFINISH                         __clewFinish                        = NULL;
PFNCLENQUEUEREADBUFFER              __clewEnqueueReadBuffer             = NULL;
PFNCLENQUEUEWRITEBUFFER             __clewEnqueueWriteBuffer            = NULL;
PFNCLENQUEUECOPYBUFFER              __clewEnqueueCopyBuffer             = NULL;
PFNCLENQUEUEREADIMAGE               __clewEnqueueReadImage              = NULL;
PFNCLENQUEUEWRITEIMAGE              __clewEnqueueWriteImage             = NULL;
PFNCLENQUEUECOPYIMAGE               __clewEnqueueCopyImage              = NULL;
PFNCLENQUEUECOPYIMAGETOBUFFER       __clewEnqueueCopyImageToBuffer      = NULL;
PFNCLENQUEUECOPYBUFFERTOIMAGE       __clewEnqueueCopyBufferToImage      = NULL;
PFNCLENQUEUEMAPBUFFER               __clewEnqueueMapBuffer              = NULL;
PFNCLENQUEUEMAPIMAGE                __clewEnqueueMapImage               = NULL;
PFNCLENQUEUEUNMAPMEMOBJECT          __clewEnqueueUnmapMemObject         = NULL;
PFNCLENQUEUENDRANGEKERNEL           __clewEnqueueNDRangeKernel          = NULL;
PFNCLENQUEUETASK                    __clewEnqueueTask                   = NULL;
PFNCLENQUEUENATIVEKERNEL            __clewEnqueueNativeKernel           = NULL;
PFNCLENQUEUEMARKER                  __clewEnqueueMarker                 = NULL;
PFNCLENQUEUEWAITFOREVENTS           __clewEnqueueWaitForEvents          = NULL;
PFNCLENQUEUEBARRIER                 __clewEnqueueBarrier                = NULL;
PFNCLGETEXTENSIONFUNCTIONADDRESS    __clewGetExtensionFunctionAddress   = NULL;
#endif  //  CLCC_GENERATE_DOCUMENTATION


//! \brief Unloads OpenCL dynamic library, should not be called directly
static void clewExit(void)
{
    if (module != NULL)
    {
        //  Ignore errors
        CLCC_DYNLIB_CLOSE(module);
        module = NULL;
    }
}

#define CLEW_CHECK_FUNCTION(f)              \
    if ((f) == NULL)                        \
    {                                       \
        CLCC_DYNLIB_CLOSE(module);          \
        module = NULL;                      \
        return CLEW_ERROR_IMPORT_FAILED;    \
    }                                       \

//! \param path path to dynamic library to load
//! \return CLEW_ERROR_OPEN_FAILED if the library could not be opened
//! CLEW_ERROR_ATEXIT_FAILED if atexit(clewExit) failed
//! CLEW_SUCCESS when the library was successfully loaded
int clewInit(const char* path)
{
    int error = 0;

    //  Check if already initialized
    if (module != NULL)
    {
        return CLEW_SUCCESS;
    }

    //  Load library
    module = CLCC_DYNLIB_OPEN(path);

    //  Check for errors
    if (module == NULL)
    {
        return CLEW_ERROR_OPEN_FAILED;
    }

    //  Set unloading
    error = atexit(clewExit);

    if (error)
    {
        //  Failure queueing atexit, shutdown with error
        CLCC_DYNLIB_CLOSE(module);
        module = NULL;

        return CLEW_ERROR_ATEXIT_FAILED;
    }

    //  Determine function entry-points
    CLEW_CHECK_FUNCTION(__clewGetPlatformIDs                = (PFNCLGETPLATFORMIDS              )CLCC_DYNLIB_IMPORT(module, "clGetPlatformIDs"));
    CLEW_CHECK_FUNCTION(__clewGetPlatformInfo               = (PFNCLGETPLATFORMINFO             )CLCC_DYNLIB_IMPORT(module, "clGetPlatformInfo"));
    CLEW_CHECK_FUNCTION(__clewGetDeviceIDs                  = (PFNCLGETDEVICEIDS                )CLCC_DYNLIB_IMPORT(module, "clGetDeviceIDs"));
    CLEW_CHECK_FUNCTION(__clewGetDeviceInfo                 = (PFNCLGETDEVICEINFO               )CLCC_DYNLIB_IMPORT(module, "clGetDeviceInfo"));
    CLEW_CHECK_FUNCTION(__clewCreateContext                 = (PFNCLCREATECONTEXT               )CLCC_DYNLIB_IMPORT(module, "clCreateContext"));
    CLEW_CHECK_FUNCTION(__clewCreateContextFromType         = (PFNCLCREATECONTEXTFROMTYPE       )CLCC_DYNLIB_IMPORT(module, "clCreateContextFromType"));
    CLEW_CHECK_FUNCTION(__clewRetainContext                 = (PFNCLRETAINCONTEXT               )CLCC_DYNLIB_IMPORT(module, "clRetainContext"));
    CLEW_CHECK_FUNCTION(__clewReleaseContext                = (PFNCLRELEASECONTEXT              )CLCC_DYNLIB_IMPORT(module, "clReleaseContext"));
    CLEW_CHECK_FUNCTION(__clewGetContextInfo                = (PFNCLGETCONTEXTINFO              )CLCC_DYNLIB_IMPORT(module, "clGetContextInfo"));
    CLEW_CHECK_FUNCTION(__clewCreateCommandQueue            = (PFNCLCREATECOMMANDQUEUE          )CLCC_DYNLIB_IMPORT(module, "clCreateCommandQueue"));
    CLEW_CHECK_FUNCTION(__clewRetainCommandQueue            = (PFNCLRETAINCOMMANDQUEUE          )CLCC_DYNLIB_IMPORT(module, "clRetainCommandQueue"));
    CLEW_CHECK_FUNCTION(__clewReleaseCommandQueue           = (PFNCLRELEASECOMMANDQUEUE         )CLCC_DYNLIB_IMPORT(module, "clReleaseCommandQueue"));
    CLEW_CHECK_FUNCTION(__clewGetCommandQueueInfo           = (PFNCLGETCOMMANDQUEUEINFO         )CLCC_DYNLIB_IMPORT(module, "clGetCommandQueueInfo"));
    CLEW_CHECK_FUNCTION(__clewSetCommandQueueProperty       = (PFNCLSETCOMMANDQUEUEPROPERTY     )CLCC_DYNLIB_IMPORT(module, "clSetCommandQueueProperty"));
    CLEW_CHECK_FUNCTION(__clewCreateBuffer                  = (PFNCLCREATEBUFFER                )CLCC_DYNLIB_IMPORT(module, "clCreateBuffer"));
    CLEW_CHECK_FUNCTION(__clewCreateImage2D                 = (PFNCLCREATEIMAGE2D               )CLCC_DYNLIB_IMPORT(module, "clCreateImage2D"));
    CLEW_CHECK_FUNCTION(__clewCreateImage3D                 = (PFNCLCREATEIMAGE3D               )CLCC_DYNLIB_IMPORT(module, "clCreateImage3D"));
    CLEW_CHECK_FUNCTION(__clewRetainMemObject               = (PFNCLRETAINMEMOBJECT             )CLCC_DYNLIB_IMPORT(module, "clRetainMemObject"));
    CLEW_CHECK_FUNCTION(__clewReleaseMemObject              = (PFNCLRELEASEMEMOBJECT            )CLCC_DYNLIB_IMPORT(module, "clReleaseMemObject"));
    CLEW_CHECK_FUNCTION(__clewGetSupportedImageFormats      = (PFNCLGETSUPPORTEDIMAGEFORMATS    )CLCC_DYNLIB_IMPORT(module, "clGetSupportedImageFormats"));
    CLEW_CHECK_FUNCTION(__clewGetMemObjectInfo              = (PFNCLGETMEMOBJECTINFO            )CLCC_DYNLIB_IMPORT(module, "clGetMemObjectInfo"));
    CLEW_CHECK_FUNCTION(__clewGetImageInfo                  = (PFNCLGETIMAGEINFO                )CLCC_DYNLIB_IMPORT(module, "clGetImageInfo"));
    CLEW_CHECK_FUNCTION(__clewCreateSampler                 = (PFNCLCREATESAMPLER               )CLCC_DYNLIB_IMPORT(module, "clCreateSampler"));
    CLEW_CHECK_FUNCTION(__clewRetainSampler                 = (PFNCLRETAINSAMPLER               )CLCC_DYNLIB_IMPORT(module, "clRetainSampler"));
    CLEW_CHECK_FUNCTION(__clewReleaseSampler                = (PFNCLRELEASESAMPLER              )CLCC_DYNLIB_IMPORT(module, "clReleaseSampler"));
    CLEW_CHECK_FUNCTION(__clewGetSamplerInfo                = (PFNCLGETSAMPLERINFO              )CLCC_DYNLIB_IMPORT(module, "clGetSamplerInfo"));
    CLEW_CHECK_FUNCTION(__clewCreateProgramWithSource       = (PFNCLCREATEPROGRAMWITHSOURCE     )CLCC_DYNLIB_IMPORT(module, "clCreateProgramWithSource"));
    CLEW_CHECK_FUNCTION(__clewCreateProgramWithBinary       = (PFNCLCREATEPROGRAMWITHBINARY     )CLCC_DYNLIB_IMPORT(module, "clCreateProgramWithBinary"));
    CLEW_CHECK_FUNCTION(__clewRetainProgram                 = (PFNCLRETAINPROGRAM               )CLCC_DYNLIB_IMPORT(module, "clRetainProgram"));
    CLEW_CHECK_FUNCTION(__clewReleaseProgram                = (PFNCLRELEASEPROGRAM              )CLCC_DYNLIB_IMPORT(module, "clReleaseProgram"));
    CLEW_CHECK_FUNCTION(__clewBuildProgram                  = (PFNCLBUILDPROGRAM                )CLCC_DYNLIB_IMPORT(module, "clBuildProgram"));
    CLEW_CHECK_FUNCTION(__clewUnloadCompiler                = (PFNCLUNLOADCOMPILER              )CLCC_DYNLIB_IMPORT(module, "clUnloadCompiler"));
    CLEW_CHECK_FUNCTION(__clewGetProgramInfo                = (PFNCLGETPROGRAMINFO              )CLCC_DYNLIB_IMPORT(module, "clGetProgramInfo"));
    CLEW_CHECK_FUNCTION(__clewGetProgramBuildInfo           = (PFNCLGETPROGRAMBUILDINFO         )CLCC_DYNLIB_IMPORT(module, "clGetProgramBuildInfo"));
    CLEW_CHECK_FUNCTION(__clewCreateKernel                  = (PFNCLCREATEKERNEL                )CLCC_DYNLIB_IMPORT(module, "clCreateKernel"));
    CLEW_CHECK_FUNCTION(__clewCreateKernelsInProgram        = (PFNCLCREATEKERNELSINPROGRAM      )CLCC_DYNLIB_IMPORT(module, "clCreateKernelsInProgram"));
    CLEW_CHECK_FUNCTION(__clewRetainKernel                  = (PFNCLRETAINKERNEL                )CLCC_DYNLIB_IMPORT(module, "clRetainKernel"));
    CLEW_CHECK_FUNCTION(__clewReleaseKernel                 = (PFNCLRELEASEKERNEL               )CLCC_DYNLIB_IMPORT(module, "clReleaseKernel"));
    CLEW_CHECK_FUNCTION(__clewSetKernelArg                  = (PFNCLSETKERNELARG                )CLCC_DYNLIB_IMPORT(module, "clSetKernelArg"));
    CLEW_CHECK_FUNCTION(__clewGetKernelInfo                 = (PFNCLGETKERNELINFO               )CLCC_DYNLIB_IMPORT(module, "clGetKernelInfo"));
    CLEW_CHECK_FUNCTION(__clewGetKernelWorkGroupInfo        = (PFNCLGETKERNELWORKGROUPINFO      )CLCC_DYNLIB_IMPORT(module, "clGetKernelWorkGroupInfo"));
    CLEW_CHECK_FUNCTION(__clewWaitForEvents                 = (PFNCLWAITFOREVENTS               )CLCC_DYNLIB_IMPORT(module, "clWaitForEvents"));
    CLEW_CHECK_FUNCTION(__clewGetEventInfo                  = (PFNCLGETEVENTINFO                )CLCC_DYNLIB_IMPORT(module, "clGetEventInfo"));
    CLEW_CHECK_FUNCTION(__clewRetainEvent                   = (PFNCLRETAINEVENT                 )CLCC_DYNLIB_IMPORT(module, "clRetainEvent"));
    CLEW_CHECK_FUNCTION(__clewReleaseEvent                  = (PFNCLRELEASEEVENT                )CLCC_DYNLIB_IMPORT(module, "clReleaseEvent"));
    CLEW_CHECK_FUNCTION(__clewGetEventProfilingInfo         = (PFNCLGETEVENTPROFILINGINFO       )CLCC_DYNLIB_IMPORT(module, "clGetEventProfilingInfo"));
    CLEW_CHECK_FUNCTION(__clewFlush                         = (PFNCLFLUSH                       )CLCC_DYNLIB_IMPORT(module, "clFlush"));
    CLEW_CHECK_FUNCTION(__clewFinish                        = (PFNCLFINISH                      )CLCC_DYNLIB_IMPORT(module, "clFinish"));
    CLEW_CHECK_FUNCTION(__clewEnqueueReadBuffer             = (PFNCLENQUEUEREADBUFFER           )CLCC_DYNLIB_IMPORT(module, "clEnqueueReadBuffer"));
    CLEW_CHECK_FUNCTION(__clewEnqueueWriteBuffer            = (PFNCLENQUEUEWRITEBUFFER          )CLCC_DYNLIB_IMPORT(module, "clEnqueueWriteBuffer"));
    CLEW_CHECK_FUNCTION(__clewEnqueueCopyBuffer             = (PFNCLENQUEUECOPYBUFFER           )CLCC_DYNLIB_IMPORT(module, "clEnqueueCopyBuffer"));
    CLEW_CHECK_FUNCTION(__clewEnqueueReadImage              = (PFNCLENQUEUEREADIMAGE            )CLCC_DYNLIB_IMPORT(module, "clEnqueueReadImage"));
    CLEW_CHECK_FUNCTION(__clewEnqueueWriteImage             = (PFNCLENQUEUEWRITEIMAGE           )CLCC_DYNLIB_IMPORT(module, "clEnqueueWriteImage"));
    CLEW_CHECK_FUNCTION(__clewEnqueueCopyImage              = (PFNCLENQUEUECOPYIMAGE            )CLCC_DYNLIB_IMPORT(module, "clEnqueueCopyImage"));
    CLEW_CHECK_FUNCTION(__clewEnqueueCopyImageToBuffer      = (PFNCLENQUEUECOPYIMAGETOBUFFER    )CLCC_DYNLIB_IMPORT(module, "clEnqueueCopyImageToBuffer"));
    CLEW_CHECK_FUNCTION(__clewEnqueueCopyBufferToImage      = (PFNCLENQUEUECOPYBUFFERTOIMAGE    )CLCC_DYNLIB_IMPORT(module, "clEnqueueCopyBufferToImage"));
    CLEW_CHECK_FUNCTION(__clewEnqueueMapBuffer              = (PFNCLENQUEUEMAPBUFFER            )CLCC_DYNLIB_IMPORT(module, "clEnqueueMapBuffer"));
    CLEW_CHECK_FUNCTION(__clewEnqueueMapImage               = (PFNCLENQUEUEMAPIMAGE             )CLCC_DYNLIB_IMPORT(module, "clEnqueueMapImage"));
    CLEW_CHECK_FUNCTION(__clewEnqueueUnmapMemObject         = (PFNCLENQUEUEUNMAPMEMOBJECT       )CLCC_DYNLIB_IMPORT(module, "clEnqueueUnmapMemObject"));
    CLEW_CHECK_FUNCTION(__clewEnqueueNDRangeKernel          = (PFNCLENQUEUENDRANGEKERNEL        )CLCC_DYNLIB_IMPORT(module, "clEnqueueNDRangeKernel"));
    CLEW_CHECK_FUNCTION(__clewEnqueueTask                   = (PFNCLENQUEUETASK                 )CLCC_DYNLIB_IMPORT(module, "clEnqueueTask"));
    CLEW_CHECK_FUNCTION(__clewEnqueueNativeKernel           = (PFNCLENQUEUENATIVEKERNEL         )CLCC_DYNLIB_IMPORT(module, "clEnqueueNativeKernel"));
    CLEW_CHECK_FUNCTION(__clewEnqueueMarker                 = (PFNCLENQUEUEMARKER               )CLCC_DYNLIB_IMPORT(module, "clEnqueueMarker"));
    CLEW_CHECK_FUNCTION(__clewEnqueueWaitForEvents          = (PFNCLENQUEUEWAITFOREVENTS        )CLCC_DYNLIB_IMPORT(module, "clEnqueueWaitForEvents"));
    CLEW_CHECK_FUNCTION(__clewEnqueueBarrier                = (PFNCLENQUEUEBARRIER              )CLCC_DYNLIB_IMPORT(module, "clEnqueueBarrier"));
    CLEW_CHECK_FUNCTION(__clewGetExtensionFunctionAddress   = (PFNCLGETEXTENSIONFUNCTIONADDRESS )CLCC_DYNLIB_IMPORT(module, "clGetExtensionFunctionAddress"));

    return CLEW_SUCCESS;
}

//! \param error CL error code
//! \return a string representation of the error code
const char* clewErrorString(cl_int error)
{
    static const char* strings[] =
    {
        // Error Codes
          "CL_SUCCESS"                                  //   0
        , "CL_DEVICE_NOT_FOUND"                         //  -1
        , "CL_DEVICE_NOT_AVAILABLE"                     //  -2
        , "CL_COMPILER_NOT_AVAILABLE"                   //  -3
        , "CL_MEM_OBJECT_ALLOCATION_FAILURE"            //  -4
        , "CL_OUT_OF_RESOURCES"                         //  -5
        , "CL_OUT_OF_HOST_MEMORY"                       //  -6
        , "CL_PROFILING_INFO_NOT_AVAILABLE"             //  -7
        , "CL_MEM_COPY_OVERLAP"                         //  -8
        , "CL_IMAGE_FORMAT_MISMATCH"                    //  -9
        , "CL_IMAGE_FORMAT_NOT_SUPPORTED"               //  -10
        , "CL_BUILD_PROGRAM_FAILURE"                    //  -11
        , "CL_MAP_FAILURE"                              //  -12

        , ""    //  -13
        , ""    //  -14
        , ""    //  -15
        , ""    //  -16
        , ""    //  -17
        , ""    //  -18
        , ""    //  -19

        , ""    //  -20
        , ""    //  -21
        , ""    //  -22
        , ""    //  -23
        , ""    //  -24
        , ""    //  -25
        , ""    //  -26
        , ""    //  -27
        , ""    //  -28
        , ""    //  -29

        , "CL_INVALID_VALUE"                            //  -30
        , "CL_INVALID_DEVICE_TYPE"                      //  -31
        , "CL_INVALID_PLATFORM"                         //  -32
        , "CL_INVALID_DEVICE"                           //  -33
        , "CL_INVALID_CONTEXT"                          //  -34
        , "CL_INVALID_QUEUE_PROPERTIES"                 //  -35
        , "CL_INVALID_COMMAND_QUEUE"                    //  -36
        , "CL_INVALID_HOST_PTR"                         //  -37
        , "CL_INVALID_MEM_OBJECT"                       //  -38
        , "CL_INVALID_IMAGE_FORMAT_DESCRIPTOR"          //  -39
        , "CL_INVALID_IMAGE_SIZE"                       //  -40
        , "CL_INVALID_SAMPLER"                          //  -41
        , "CL_INVALID_BINARY"                           //  -42
        , "CL_INVALID_BUILD_OPTIONS"                    //  -43
        , "CL_INVALID_PROGRAM"                          //  -44
        , "CL_INVALID_PROGRAM_EXECUTABLE"               //  -45
        , "CL_INVALID_KERNEL_NAME"                      //  -46
        , "CL_INVALID_KERNEL_DEFINITION"                //  -47
        , "CL_INVALID_KERNEL"                           //  -48
        , "CL_INVALID_ARG_INDEX"                        //  -49
        , "CL_INVALID_ARG_VALUE"                        //  -50
        , "CL_INVALID_ARG_SIZE"                         //  -51
        , "CL_INVALID_KERNEL_ARGS"                      //  -52
        , "CL_INVALID_WORK_DIMENSION"                   //  -53
        , "CL_INVALID_WORK_GROUP_SIZE"                  //  -54
        , "CL_INVALID_WORK_ITEM_SIZE"                   //  -55
        , "CL_INVALID_GLOBAL_OFFSET"                    //  -56
        , "CL_INVALID_EVENT_WAIT_LIST"                  //  -57
        , "CL_INVALID_EVENT"                            //  -58
        , "CL_INVALID_OPERATION"                        //  -59
        , "CL_INVALID_GL_OBJECT"                        //  -60
        , "CL_INVALID_BUFFER_SIZE"                      //  -61
        , "CL_INVALID_MIP_LEVEL"                        //  -62
        , "CL_INVALID_GLOBAL_WORK_SIZE"                 //  -63
    };

    if  (   (error > 0)
        ||  (error < -63)
        )
    {
        return "unknown error code (no OpenCL driver?)";
    }

    return strings[-error];
}