#import <mach-o/dyld.h>
 #import <stdlib.h>
 #import <string.h>
void *NSGLGetProcAddress(const char *name)
{
    NSSymbol symbol;
    char *symbolName;
    // UNIX Ç…Ç®ÇØÇÈ C ÇÃÉVÉìÉ{ÉãÉ}ÉìÉOÉäÉìÉOãKë•
    // Ç…è]ǡǃÅAÅe_ÅfÇëOÇ…ïtÇØÇ‹Ç∑
    symbolName = malloc (strlen (name) + 2);
    strcpy(symbolName + 1, name);
    symbolName[0] = '_';
    symbol = NULL;
    if (NSIsSymbolNameDefined (symbolName))
        symbol = NSLookupAndBindSymbol (symbolName);
    free (symbolName);
    return symbol ? NSAddressOfSymbol (symbol) : NULL;
}

ÉäÉXÉg 1. NSGLGetProcAddress

 #include <Carbon/Carbon.h>
CFBundleRef gBundleRefOpenGL = NULL;

// -------------------------

OSStatus aglInitEntryPoints (void)
{
    OSStatus err = noErr;
    const Str255 frameworkName = "\pOpenGL.framework";
    FSRefParam fileRefParam;
    FSRef fileRef;
    CFURLRef bundleURLOpenGL;

    memset(&fileRefParam, 0, sizeof(fileRefParam));
    memset(&fileRef, 0, sizeof(fileRef));

    fileRefParam.ioNamePtr  = frameworkName;
    fileRefParam.newRef = &fileRef;

    // ÅuFrameworksÅvÉfÉBÉåÉNÉgÉäÅ^ÉtÉHÉãÉ_
    err = FindFolder (kSystemDomain, kFrameworksFolderType, false,
                      &fileRefParam.ioVRefNum, &fileRefParam.ioDirID);
    if (noErr != err) {
        DebugStr ("\pCould not find frameworks folder");
        return err;
    }
    err = PBMakeFSRefSync (&fileRefParam); // ÉtÉHÉãÉ_ÇéwÇ∑ FSRef ÇçÏê¨Ç∑ÇÈ
    if (noErr != err) {
        DebugStr ("\pCould make FSref to frameworks folder");
        return err;
    }
    // ÉtÉHÉãÉ_ÇéwÇ∑ URL ÇçÏê¨Ç∑ÇÈ
    bundleURLOpenGL = CFURLCreateFromFSRef (kCFAllocatorDefault,
                                            &fileRef);
    if (!bundleURLOpenGL) {
        DebugStr ("\pCould create OpenGL Framework bundle URL");
        return paramErr;
    }
    // GL ÇÃÉoÉìÉhÉãÇéwÇ∑ Ref ÇçÏê¨Ç∑ÇÈ
    gBundleRefOpenGL = CFBundleCreate (kCFAllocatorDefault,
                                       bundleURLOpenGL);
    if (!gBundleRefOpenGL) {
        DebugStr ("\pCould not create OpenGL Framework bundle");
        return paramErr;
    }
    CFRelease (bundleURLOpenGL); // çÏê¨ÇµÇΩÉoÉìÉhÉãÇâï˙Ç∑ÇÈ
    // ÉoÉìÉhÉãÇÃÉRÅ[ÉhÇê≥ǵÇ≠ÉçÅ[ÉhÇ≈Ç´ÇΩÇÁÅAÉtÉ@ÉìÉNÉVÉáÉìÇíTÇ∑
    if (!CFBundleLoadExecutable (gBundleRefOpenGL)) {
        DebugStr ("\pCould not load MachO executable");
        return paramErr;
    }
    return err;
}

// -------------------------

void aglDellocEntryPoints (void)
{
    if (gBundleRefOpenGL != NULL) {
        // ÉoÉìÉhÉãÇÃÉRÅ[ÉhÇÉAÉìÉçÅ[ÉhǵNjÇ∑
        CFBundleUnloadExecutable (gBundleRefOpenGL);
        CFRelease (gBundleRefOpenGL);
        gBundleRefOpenGL = NULL;
    }
}

// -------------------------

void * aglGetProcAddress (char * pszProc)
{
    return CFBundleGetFunctionPointerForName (gBundleRefOpenGL,
                CFStringCreateWithCStringNoCopy (NULL,
                     pszProc, CFStringGetSystemEncoding (), NULL));
}

ÉäÉXÉg 2. aglGetProcAddress

#import "NSGLGetProcAddress.h" // ÉäÉXÉg 1 Ç…Ç®ÇØÇÈ aglGetProcAddress ÉtÉ@Éì
                               // ÉNÉVÉáÉìÇéÊìæÇ∑ÇÈÉwÉbÉ_ÉtÉ@ÉCÉã

static void InitEntryPoints (void);
static void DeallocEntryPoints (void);

// ÉtÉ@ÉìÉNÉVÉáÉìÉ|ÉCÉìÉ^Ç typedef Ç≈íËã`Ç∑ÇÈ
    typedef void (*glBlendColorProcPtr)(GLclampf red,
                                        GLclampf green,
                                        GLclampf blue,
                                        GLclampf alpha);
    typedef void (*glBlendEquationProcPtr)(GLenum mode);
    typedef void (*glDrawRangeElementsProcPtr)(GLenum mode,
                                               GLuint start,
                                               GLuint end,
                                               GLsizei count,
                                               GLenum type,
                                               const GLvoid *indices);

// ÉtÉ@ÉìÉNÉVÉáÉìÉ|ÉCÉìÉ^êÈåæ
// íçà”ÅFÉtÉ@ÉìÉNÉVÉáÉìñºÇǪÇÃÇ‹Ç‹égópǵǻǢDZÇΔ
// pfXXX ÇÕÅAÅuÉtÉ@ÉìÉNÉVÉáÉìÇ÷ÇÃÉ|ÉCÉìÉ^ÅvÇ
// Çï\Ç∑è»ó™å`ÇΔǵǃëIÇÒÇæ
    glBlendColorProcPtr pfglBlendColor = NULL;
    glBlendEquationProcPtr pfglBlendEquation = NULL;
    glDrawRangeElementsProcPtr pfglDrawRangeElements  = NULL;

// ==========================

static void InitEntryPoints (void)
{
    pfglBlendColor = (glBlendColorProcPtr)
                         NSGLGetProcAddress ("glBlendColor");
    pfglBlendEquation = (glBlendEquationProcPtr)
                            NSGLGetProcAddress ("glBlendEquation");
    pfglDrawRangeElements = (glDrawRangeElementsProcPtr)
                                NSGLGetProcAddress ("glDrawRangeElements");
}

// -------------------------

static void DeallocEntryPoints (void)
{
    pfglBlendColor = NULL;
    pfglBlendEquation = NULL;
    pfglDrawRangeElements = NULL;;
}

ÉäÉXÉg 3. NSGLGetProcAddress ÇÃégópó·

#include "aglGetProcAddress.h" // ÉäÉXÉg 2 Ç…Ç®ÇØÇÈ aglGetProcAddress Ét
                               // É@ÉìÉNÉVÉáÉìÇéÊìæÇ∑ÇÈÉwÉbÉ_ÉtÉ@ÉCÉã

static OSStatus InitEntryPoints (void);
static void DeallocEntryPoints (void);

// ÉtÉ@ÉìÉNÉVÉáÉìÉ|ÉCÉìÉ^Ç typedef Ç≈íËã`Ç∑ÇÈ
    typedef void (*glBlendColorProcPtr)(GLclampf red,
                                        GLclampf green,
                                        GLclampf blue,
                                        GLclampf alpha);
    typedef void (*glBlendEquationProcPtr)(GLenum mode);
    typedef void (*glDrawRangeElementsProcPtr)(GLenum mode,
                                               GLuint start,
                                               GLuint end,
                                               GLsizei count,
                                               GLenum type,
                                               const GLvoid *indices);

// ÉtÉ@ÉìÉNÉVÉáÉìÉ|ÉCÉìÉ^êÈåæ
// íçà”ÅFÉtÉ@ÉìÉNÉVÉáÉìñºÇǪÇÃÇ‹Ç‹égópǵǻǢDZÇΔ
// pfXXX ÇÕÅAÅuÉtÉ@ÉìÉNÉVÉáÉìÇ÷ÇÃÉ|ÉCÉìÉ^ÅvÇ
// ï\Ç∑è»ó™å`ÇΔǵǃëIÇÒÇæ
    glBlendColorProcPtr pfglBlendColor = NULL;
    glBlendEquationProcPtr pfglBlendEquation = NULL;
    glDrawRangeElementsProcPtr pfglDrawRangeElements  = NULL;

// ==========================

static OSStatus InitEntryPoints (void)
{
    OSStatus err = aglInitEntryPoints (); // ÉoÉìÉhÉãÇÃèâä˙âª
    if (noErr == err) {
        pfglBlendColor = (glBlendColorProcPtr)
                            aglGetProcAddress ("glBlendColor");
        pfglBlendEquation = (glBlendEquationProcPtr)
                                aglGetProcAddress ("glBlendEquation");
        pfglDrawRangeElements = (glDrawRangeElementsProcPtr)
                                    aglGetProcAddress ("glDrawRangeElements");
    }
    return err;
}

// -------------------------

static void DeallocEntryPoints (void)
{
    pfglBlendColor = NULL;
    pfglBlendEquation = NULL;
    pfglDrawRangeElements = NULL;;
    aglDellocEntryPoints (); // ÉoÉìÉhÉãÇÃîjä¸
}

ÉäÉXÉg 4. aglGetProcAddress ÇÃégópó·