Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!munnari.oz.au!diemen!ecc.tased.oz.au!ecc_jim
From: ecc_jim@ecc.tased.oz.au
Newsgroups: comp.sys.acorn
Subject: Re: How to create menus in C
Message-ID: <1991Jan31.091559.238@ecc.tased.oz.au>
Date: 30 Jan 91 23:15:59 GMT
References: <740@.econ.vu.nl>
Lines: 59

In article <740@.econ.vu.nl>, walther@econ.vu.nl (Walther Schoonenberg/10000) writes:
> 
> Hello all of you,
> 
> I've got a little RISCOS_LIB C problem. I don't know how to make a
> nested menu structure in C. If you do, for instance, the following:
> 
>   menu temp[5];
> 
>   temp[0] = menu_new("Main menu",">Info,Why,Quit");
>   temp[1] = menu_new("Why","Can't,I,Do,This?");
>   menu_submenu(temp[0],2,temp[1]);
>   temp[2] = menu_new("I","Do,This?");
>   menu_submenu(temp[1],2,temp[2]);
>   temp[3] = menu_new("Do","This?");
>   menu_submenu(temp[1],3,temp[3]);
> 
>   return temp[0];
> 
> In this example I want to create this menu structure:
> 
> 
> Main Menu   first level  second level
> ---------
> Info  ->    InfoProg box
> Why   ->    Why
> Quit        ---
>             Can't
>             I       ->  I
>                         --
>                         Do
>                         This?
>             Do      ->  Do
>             This?       --
>                         This?
> 
> 
> This doesn't work. The temp[[3] submenu disappears completely, without
> any warning or error message. Why? Maybe this is not a 'strict hierarchy'
> about which the manual talks. But what is a strict hierarchy exactly and
> if it is not possible to use menu_submenu to create the above menu
> structure, how could you make such a menu structure ?
> 
> Any help greatly appreciated.
> 
> Walther Schoonenberg


From the small piece of code that you have submitted, I am guessing that you
have placed all the above in a function - including the declaration of temp.

This means the local array temp[5] is being returned to the free memory pool at
the end of the function with only the value of temp[0] being passed back to the
calling function. Try making all your menu handles reside in static variables.

Jim Palfreyman

Elizabeth Computer Centre, Tasmania, Australia
e-mail: ecc_jim@ecc.tased.oz.au