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Re: Online RISC OS colour converter

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<6b45a6aa-08ca-4cbc-b2c9-15746c3012aa@u26g2000vby.googlegroups.com>,
   Gerph <gerph@gerph.org> wrote:
> Amusingly (to me) 'Use TaskWindow' isn't actually on the list, despite it
> being a general encompassment of 3 or 4 of the things on the list. ISTR
> the former has pathological cases which can occur more the more you use
> it, which corrupt the memory that is used for its buffers (RMA in the
> failing versions, IIRC). The latter has race conditions aplenty, which
> affect multiple other OS components. Worst case is that you stiff the
> machine completely when you trigger it. Next worst is that you trigger a
> repeating exception error box. It is increasingly likely the higher the
> load on the OS, which is (generally) the times at which you wish to use it.

Yes. I did a classic cock-up one time in writing a command line program
which processed a sprite file in some way. The processing involved
redirecting output to a sprite, doing something and restoring output. This
is fine if you run it in a command window or some other single-tasking
context.

As soon as you run it in a Task Window, there's the risk that it pre-empts
away from you in the middle of the process and things get rather confused
because output is still redirected into the sprite...

In the end, I had to bodge a work-around which checks to see if the program
is running in a Task Windows (SWI TaskWindow_TaskInfo) and if it is, push
something onto the SVC stack before the sprite manipulation and pop it
afterwards (the Task Window won't pre-empt when the SVC stack is non-empty).

As you say: Tra-la-la-la.

Ta,

Steve

-- 
Steve Revill @ Home
Note: All opinions expressed herein are my own.

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Online RISC OS colour converter chrisbazley@bigfoot.com - 2011-04-22 18:12 -0700
  Re: Online RISC OS colour converter Gerph <gerph@gerph.org> - 2011-04-23 08:40 -0700
    Re: Online RISC OS colour converter chrisbazley@bigfoot.com - 2011-04-24 06:28 -0700
      Re: Online RISC OS colour converter Alan Wrigley <spamhater@keepyourfilthyspamtoyourself.co.uk> - 2011-04-24 16:21 +0100
        Re: Online RISC OS colour converter Alan Wrigley <spamhater@keepyourfilthyspamtoyourself.co.uk> - 2011-04-24 16:26 +0100
      Re: Online RISC OS colour converter Gerph <gerph@gerph.org> - 2011-04-26 13:44 -0700
        Re: Online RISC OS colour converter "Ste (news)" <steve@revi11.plus.com> - 2011-04-27 14:00 +0100
          Re: Online RISC OS colour converter Gerph <gerph@gerph.org> - 2011-04-30 05:25 -0700
          Re: Online RISC OS colour converter Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2011-04-28 13:07 +0200
            Re: Online RISC OS colour converter chrisbazley@bigfoot.com - 2011-04-28 12:28 -0700
              Re: Online RISC OS colour converter "Ste (news)" <steve@revi11.plus.com> - 2011-05-03 12:06 +0100
  Re: Online RISC OS colour converter jgharston <jgh@arcade.demon.co.uk> - 2011-05-02 15:48 -0700
    Re: Online RISC OS colour converter chrisbazley@bigfoot.com - 2011-05-02 16:29 -0700

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