Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!apple!amdahl!kevin
From: kevin@uts.amdahl.com (Kevin Clague)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Programming multiple Menu Selections
Message-ID: <172S26aXLs10100WHNE@amdahl.uts.amdahl.com>
Date: 10 Apr 89 13:22:15 GMT
References: <2124@pur-phy>
Reply-To: kevin@amdahl.uts.amdahl.com (Kevin Clague)
Organization: Amdahl Corporation,  Sunnyvale, CA 94086
Lines: 55

In article <2124@pur-phy> murphy@newton.physics.purdue.edu (William J. Murphy) writes:
>
>I have been trying to figure out why I have a bug in a program of mine
>which uses/supports multiple menu selections.  I have 2 menus, one with one
>item, the other with two items. The FIRST time that I select Menu1 Item1,or
>Menu2 Item2,
>I get locked into a loop with number = 0.  The FIRST time that I select Menu2
>Item1, everything from then on works fine.
>
>I have isolated the problem as what is being returned by the function
>number = ItemAddress(main_menu[0], number)->NextSelect;
>
>number is intially given a value from
>message = (struct IntuiMessage *)GetMsg(window->UserPort);
>class   = message->Class;
>code    = message->Code;
>switch(class)
>{
>    case MENUPICK:
>        handle_main_menu(code);
>	break;
>}
>
>handle_main_menu(number)
>
>From what I have discerned from Mortimore, if number is not a valid 
>menuNumber then ItemAddress will return a NULL.  Is it correct to trap
>for this potential error condition?  Maybe something like this?
>
>if ((number = ItemAddress(main_menu[0], number)-NextSelect) == NULL)
Could this be your problem?         ^^^

  What you want to do is pass it the addess of your menu chains, not
the contents of the first menu item.  Otherwise you seem to be on the
right track.

>    number = MENUNULL;
>
>I use (number != MENUNULL) as a conditional test in a while loop.
>
>Finally, I guess I am asking how do others support multiple menu selections
>and is what I am doing flawed.
>Bill Murphy

  I've used the same method with good success.

Kevin
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