2 Dec
2010
2 Dec
'10
1:19 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Philip Pemberton
Sent: Thursday, December 02, 2010 1:12 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Excessive optimization (was Re: what was VMS/OpenVMS
written in?)
On Thu, 2010-12-02 at 13:32 -0700, Richard wrote:
This discussion puts me in mind of a series of columns in "C Users Journal"
about the draft ANSI standard and how it changed behaviors exhibited by some well-known
compilers at the time. The "quiet changes" were the worst: those that caused
working programs to fail if recompiled, but generated no warning. In developing the
standard, some things came down to judgement calls, since you could demonstrate successful
implementations that were on either side of the question! -- Ian
In article <AANLkTi=9NwjfxZvaz2H-btkzt8q-
c9ErbpNYW+hMfMe=(a)mail.gmail.com>gt;,
Ethan Dicks <ethan.dicks at gmail.com>
writes:
Oh, it's valid. A C for() loop has the following syntax:
for (initialiser, condition, loop)
Initialiser is run once before the first loop.
Condition is validated at the beginning of the loop. If it is TRUE,
then
the loop carries on regardless. If the condition is omitted, it is
assumed to be TRUE.
Loop is executed once for each time the loop completes, at the end of
the loop.
So this:
for (i=0; i<10; i++) {
printf("foo %d\n", i);
}
Is equivalent to:
i=0;
while (i<10) {
printf("foo %d\n", i);
i++;
}
Kernighan & Ritchie "The C Programming Language", Second Edition
"Revised for ANSI C". Page 60, section 3.5, paragraph 4, last line. I'd
reference the ANSI standard, but K&R seemed just as good (and more
accessible) 8^)
for (;;)
;
I don't see how this is an infinite loop requiring reset of the
processor to escape since the condition clause is empty. In fact,
since the condition clause is empty, I'm not even sure its
syntactically valid, but C is strange enough that it may be
syntactically valid but not intuititve.