Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: setjmp/longjmp question
Message-ID: <1989Mar3.162617.16755@utzoo.uucp>
Organization: U of Toronto Zoology
References: <8514@polyslo.CalPoly.EDU> <1989Feb26.012335.12938@utzoo.uucp> <419@chem.ucsd.EDU>
Date: Fri, 3 Mar 89 16:26:17 GMT

In article <419@chem.ucsd.EDU> tps@chem.ucsd.edu (Tom Stockfisch) writes:
>>>Would longjmp() clober all local variables...
>
>>It could.
>
>Even if the local variable is an array?

Yes.  Absolutely no promises are made about the fate of local variables,
in the absence of "volatile".  Don't forget that there are machines in
which registers are addressable, and on those machines it is possible
(although perhaps seldom sensible) to put (small) arrays in registers.
Also, it isn't necessarily true that arrays *must* be in addressable
storage.  In the general case, with pointers being passed around with
wild abandon, they have to be.  But many functions use arrays in much
more disciplined ways, such that the compiler can completely understand
what is going on.  In such cases, a clever compiler might be able to
put arrays into things like Cray vector registers.
-- 
The Earth is our mother;       |     Henry Spencer at U of Toronto Zoology
our nine months are up.        | uunet!attcan!utzoo!henry henry@zoo.toronto.edu