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From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: net.lang.c
Subject: Re: *p++ = *p results?
Message-ID: <2034@brl-smoke.ARPA>
Date: Mon, 24-Mar-86 01:12:59 EST
Article-I.D.: brl-smok.2034
Posted: Mon Mar 24 01:12:59 1986
Date-Received: Wed, 26-Mar-86 04:27:58 EST
References: <312@imagen.UUCP>
Reply-To: gwyn@brl.ARPA
Distribution: net
Organization: Ballistic Research Lab (BRL)
Lines: 15

In article <312@imagen.UUCP> kevin@imagen.UUCP (Kevin L. Malloy) writes:
>In the statement *p++ = *p; what will be the result?  Will p be equal
>to itself or will p be equal to the next value it is pointing to?
>In other words should p be incremented after it is evaluated or should
>p be incremented after the assignment operation is finished?-- 

Obviously `p' equals itself!  I will assume you mean "does `p'
point to the next value after the one `p' initially pointed to?"

The technically correct answer is, `p' must be incremented
by the time the next "sequence point" (defined by X3J11) is
reached.  My copy of the draft standard is not at hand at the
moment, but I believe there is no sequence point until after
the assignment.  That would mean that either result is legal;
in other words, don't write code like this.