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From: pete@topaz.berkeley.edu
Newsgroups: net.micro.amiga
Subject: Re: beta 4 (& re-entrant code)
Message-ID: <1103@jade.BERKELEY.EDU>
Date: Sun, 17-Aug-86 03:36:21 EDT
Article-I.D.: jade.1103
Posted: Sun Aug 17 03:36:21 1986
Date-Received: Mon, 18-Aug-86 00:40:21 EDT
References: <661@usc-oberon.UUCP> <1468@amiga.amiga.UUCP> <870@tekigm.UUCP>
Sender: usenet@jade.BERKELEY.EDU
Reply-To: pete@topaz.berkeley.edu.UUCP (Pete Goodeve)
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Organization: University of California, Berkeley
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In article <870@tekigm.UUCP> phils@tekigm.UUCP (Phil Staub) writes:
>In article <1468.....> neil@rocky.UUCP (Neil Katin) writes:
>>
>>HOWEVER, your code needs to be fully reentrant to live on this list.
>>Neither lattice C nor emacs are reentrant.  It turns out that all BCPL
>>programs are.  C programs can be written so that they are reentrant,
>>but they typically are not.
>>
>
>Question:
>
>I am interested to know what it is about the lattice C compiler that
>generates non-reentrant code. I am not familiar with this compiler,
>but (at least according to my understanding) any code which does not utilize
>static or extern variables (i.e., only uses automatics or registers) should
>be re-entrant in C. I also know that with some compilers, functions which
>return structures do so in a non-reentrant way. Are these the only
>non-reentrancies to which you refer, or is there a gap in my understanding
>about reentrancy, or is there something else about Lattice which is
>non-reentrant.
>
>Thanks


The only thing that is really non-reentrant about (any) C on the Amiga is
the way start-up is handled.  Certain static locations -- defined at the
assembly level -- are filled with items like the top and base of the stack,
pointer to the command line, and so on.

If you try to enter the same loaded segment of code (with the same static
data area) a second time, you're bound to screw things up.

The answer has to be to write an alternative startup.obj that puts the data
somewhere that's exclusive to that process.  I'm working on't....

						Pete G.