C++ - Deaktivieren von VSync unter OpenGL

//Download wglext.h from http://oss.sgi.com/projects/ogl-sample/sdk.html
#include <gl\wglext.h>

PFNWGLSWAPINTERVALEXTPROC wglSwapIntervalEXT = NULL;
PFNWGLGETSWAPINTERVALEXTPROC wglGetSwapIntervalEXT = NULL;


//from NeHe Lesson 45
bool IsExtensionSupported( char* szTargetExtension )
{
    const unsigned char *pszExtensions = NULL;
    const unsigned char *pszStart;
    unsigned char *pszWhere, *pszTerminator;

    // Extension names should not have spaces
    pszWhere = (unsigned char *) strchr( szTargetExtension, ' ' );
    if( pszWhere || *szTargetExtension == '\0' )
        return false;

    // Get Extensions String
    pszExtensions = glGetString( GL_EXTENSIONS );

    // Search The Extensions String For An Exact Copy
    pszStart = pszExtensions;
    for(;;)
    {
        pszWhere = (unsigned char *) strstr( (const char *) pszStart, szTargetExtension );
        if( !pszWhere )
            break;
        pszTerminator = pszWhere + strlen( szTargetExtension );
        if( pszWhere == pszStart || *( pszWhere - 1 ) == ' ' )
            if( *pszTerminator == ' ' || *pszTerminator == '\0' )
                return true;
        pszStart = pszTerminator;
    }
    return false;
}

bool InitVSync()
{
   if (IsExtensionSupported("WGL_EXT_swap_control"))
   {
      wglSwapIntervalEXT = (PFNWGLSWAPINTERVALEXTPROC)
          wglGetProcAddress("wglSwapIntervalEXT");
      wglGetSwapIntervalEXT = (PFNWGLGETSWAPINTERVALEXTPROC)
          wglGetProcAddress("wglGetSwapIntervalEXT");
      return true;
   }
   return false;// WGL_EXT_swap_control not supported
}
bool SetVSync(bool VSync)
{
    if(!wglSwapIntervalEXT) return false;
    wglSwapIntervalEXT(VSync);
    return true;
}
bool GetVSync(bool* VSync)
{
    if(!wglGetSwapIntervalEXT) return false;//VSynce value is not valid...
    *VSync = wglGetSwapIntervalEXT();
    return true;
}