Path: utzoo!news-server.csri.toronto.edu!rpi!uupsi!sunic!liuida!d88ricwe
From: d88ricwe@odalix.ida.liu.se (Rickard Westman)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Intuition beginner's problem
Keywords: multitasking intuition
Message-ID: <1991Mar18.111652.777@ida.liu.se>
Date: 18 Mar 91 11:16:52 GMT
References: <1511@tau.sm.luth.se>
Sender: news@ida.liu.se (News Subsystem)
Distribution: comp
Organization: CIS Dept, Univ of Linkoping, Sweden
Lines: 25

d89-rbn@sm.luth.se (Robert Buren) writes:

>I'm learning how to use multitasking in my programs, but I seem to have
>run into a problem here. I made a very simple program that opens up a
>window and attaches some menus to it, and everything worked just fine.
>The next step was to make an About routine that just opens up another
>window and writes my name in it.. Still no problems. But(!) then I wanted
>the Aboutroutine to run as a childtask. Hello Guru.
> The program works just fine up to this line:

>AboutTask = CreateTask("About",0,AboutCode,5000);

Could it be that you're using the small code/data model with your compiler?
In that case, most references to global data are made through a base register
(usually a4).  This will not be correctly initialized if one of your functions
get called from an interrupt routine or from the scheduler.  

If you are using Manx, the single line

geta4();

added at the very start of your AboutCode() could solve your problem.
Lattice/SAS use something similar, I think.  Check it with the manual.
--
Rickard Westman, University of Linkoping, Sweden