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From: dgary@ecsvax.UUCP
Newsgroups: net.lang
Subject: Re: (Re:)* Modula-2, exceptions, C
Message-ID: <2871@ecsvax.UUCP>
Date: Mon, 9-Jul-84 17:07:32 EDT
Article-I.D.: ecsvax.2871
Posted: Mon Jul  9 17:07:32 1984
Date-Received: Wed, 11-Jul-84 03:39:18 EDT
References: yale-com.4096
Lines: 20

>From: leichter@yale-comix.UUCP (Jerry Leichter) Fri Jun 29 10:48:05 1984
>... there IS a valid argument to be made that requiring an & at the point
>of call has the salutory effect that it is possible to determine BY LOOKING AT
>THE CALLING CODE ONLY, what values may potentially be affected by the call.
>Think about it:  In C the ONLY things that can directly change the value of
>a variable are =, op=, ++, and --, and the only thing that can cause a value
>to be change indirectly is &.

Actually, arrays are effectively passed by reference in C, since what
is value-copied is a constant pointer.  A stylistic device (making
the first letter of an array name capital?) could serve to make this
clear, perhaps.  Nevertheless, your point is a good one.  In Pascal,
only the subroutine shows whether values are passed by reference or
by value.  In PL/I and FORTRAN only the caller determines this.  In
C it is usually clear from looking at either what is being passed.

D Gary Grady
Duke University Computation Center, Durham, NC  27706
(919) 684-4146
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