Path: chuka.playstation.co.uk!news
From: gil@snsys.com (Gil Jaysmith)
Newsgroups: scea.yaroze.programming.codewarrior
Subject: Re: Initializing the heap
Date: Fri, 31 Oct 1997 12:00:45 GMT
Organization: SN Systems
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"Wayne K. Werner" <wkwerner@con2.com> wrote:
>Yeah, but I still find it problematic to init heap in the source. 
>Heap is
>a feature of the language itself.  I think maybe GNU should be
>"upgraded" to 
>handle this issue correctly, and CW shouldn't be "downgraded" to be
>compatible.  Then compiler specific issues of heap inititialization
>would
>be no issues at all.

Everyone seems to enjoy assuming that GNU should be changed to fit in
with someone else's compiler which they happen to be using. Why
exactly is this? (GNU predates CodeWarrior; CodeWarrior could be
considered wrong on that basis for everything different which it
does.) Heap management is a library thing, not a language thing. An
initialisation call is required, and giving control of the heap-init
routine to the programmer could be said to enhance flexibility. The
fact that you didn't realise the difference until it happened isn't
necessarily your fault but certainly isn't the GNU toolchain's fault.
Insisting that GNU should be 'upgraded' so it generates
specifically-named section/segment descriptor variables for 100%
CodeWarrior compatibility comes across as a bit petulant, squire - not
to mention uninformed, since GNU 'ld' supports symbol aliasing so you
can cheerfully create all the descriptor variables you need... ;=)

<calms down>

The startup code for a particular platform invariably has to make
assumptions about what you might want to do yourself and what you
don't want to know about. Correctly initialising the GP register is
not something you'd typically care about, so startup code does that
for you. Initialisation of the heap from the end of your program to
the end of memory is *probably* safe, but dynamic loading of graphics
data circumvents that assumption, so you either need to reserve the
space in BSS or override the InitHeap call yourself. It's too bad that
you have to do this differently depending on the platform, but #ifdef
was invented for situations like this.

- Gil