/*

    File:       IconUtilCheck.c

    Contains:   According to the Tech Note OV - 16, "Inside Macintosh: More Macintosh 

                Toolbox, page 5-7, specifies that the gestaltIconUtilitiesAttr - 'icon'

                gestalt selector can be used to determine whether the icon utilities

                are present under System 7.x.   Note that this selector is included in

                the GestaltEqu files.  It turns out that this selector is not

                implemented until System Software v7.1.2.  To check for the existence of

                these utilities, use the TrapAvailable code to check for the 

                _IconDispatch, (0xABC9) trap.  The TrapAvailable code is presented in

                Inside Macintosh VI 3-8, and as sample code in many of the snippets

                on the Developer CD."

                This snippet shows how to determine whether the Icon Utilities

                are available.

    Written by: Virginia (Ginny) McCulloh   

    Copyright:  Copyright © 1995-1999 by Apple Computer, Inc., All Rights Reserved.

                You may incorporate this Apple sample source code into your program(s) without

                restriction. This Apple sample source code has been provided "AS IS" and the

                responsibility for its operation is yours. You are not permitted to redistribute

                this Apple sample source code as "Apple sample source code" after having made

                changes. If you're going to re-distribute the source, we require that you make

                it clear in the source that the code was descended from Apple sample source

                code, but that you've made changes.

    Change History (most recent first):

                8/6/1999    Karl Groethe    Updated for Metrowerks Codewarror Pro 2.1

*/

#include <stdio.h>

#include <Types.h>

#include <OSUtils.h>

#include <GestaltEqu.h>

#ifndef __TRAPS__

#include <Traps.h>

#endif

#define TrapMask        0x0800

Boolean TrapAvailable(short theTrap);

short NumToolboxTraps(void);

TrapType GetTrapType(short theTrap);

short NumToolboxTraps(void)

{

    if (NGetTrapAddress(_InitGraf, ToolTrap) == NGetTrapAddress(0xAA6E,ToolTrap))

        return 0x0200;

    else

        return 0x0400;

}

TrapType GetTrapType(short theTrap)

{

    if ((theTrap & TrapMask) > 0)

        return ToolTrap;

    else

        return OSTrap;

}

Boolean TrapAvailable(short theTrap)

{

    TrapType tType;

    Boolean isAvail;

    tType = GetTrapType(theTrap);

    if (tType == ToolTrap)

        {

            theTrap &= 0x07FF;

            if (theTrap >= NumToolboxTraps())

                theTrap = _Unimplemented;

        }

    isAvail = NGetTrapAddress(theTrap, tType) != NGetTrapAddress(_Unimplemented, ToolTrap);

    return isAvail;

}

void main(void)

{

    printf("Testing for presence of Icon Utilities\n");

    if (TrapAvailable(_IconDispatch))

        printf("Icon Utilities are available\n");

    else

        printf("Icon Utilities are not available\n");

}