Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uunet!munnari.oz.au!murtoa.cs.mu.oz.au!ditmela!yarra!bohra!ejp
From: ejp@bohra.cpg.oz (Esmond Pitt)
Newsgroups: comp.lang.c
Subject: Re: did old compilers give warning on &struct?
Keywords: & struct passing
Message-ID: <112@bohra.cpg.oz>
Date: 13 Nov 89 00:49:38 GMT
References: <465@siswat.UUCP>
Reply-To: ejp@bohra.cpg.oz (Esmond Pitt)
Organization: Computer Power Group, Melb, Australia
Lines: 26

In article <465@siswat.UUCP> buck@siswat.UUCP (A. Lester Buck) writes:
>In a recent discussion with a co-worker, he claimed that several (many?)
>early C compilers, before the support of structure passing, would give a
>warning if there was an & before a structure in a function call, similar to
>the (correct) warning for an & before an array.  He claims he and many
>others wrote a lot of code that removed the & to shut up the warnings, but
>were then caught when a later version of these compilers started supporting
>structure passing.
>
>I have _never_ heard of or used such a brain-dead compiler.  Did such
>compilers exist, and can I run into large pieces of code that don't have &
>before struct parameters passed by reference?

Before structure name arguments => pass by reference was supported,
structure name arguments were passed _by_value_. Therefore your
co-worker seems to have it back to front: as the programmer at that
time probably intended a pass-by reference rather than stacking some
potentially huge structure, there may have been C compilers which
complained if the & was _missing_. Indeed the compiler may not have
supported passing aggregates by value. (I have never seen either
behaviour.)


-- 
Esmond Pitt, Computer Power Group
ejp@bohra.cpg.oz