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| From | Dr Nick <nospam-4@temporary-address.org.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Baby X |
| References | (7 earlier) <d846d0c0-f489-4f17-b144-a0a2594081fc@googlegroups.com> <ku38so$dv0$7@dont-email.me> <21e20dde-9921-4f9e-8e4c-5ed3a3667bee@googlegroups.com> <ku3hqb$f7b$1@speranza.aioe.org> <lnk3juo9g8.fsf@nuthaus.mib.org> |
| Date | 2013-08-10 20:11 +0100 |
| Message-ID | <874naxz7h3.fsf@temporary-address.org.uk> (permalink) |
Keith Thompson <kst-u@mib.org> writes:
> glen herrmannsfeldt <gah@ugcs.caltech.edu> writes:
> [...]
>> Note that before ANSI there was no void, and it was usual for
>> functions to return int, and no return statement. I believe it
>> returns zero in that case.
>
> Falling off the end of a non-void function causes it to return an
> undefined result to the caller. If the caller attempts to use that
> value, the behavior is undefined.
>
> For backward compatibility, this:
>
> int func(void) {
> /* do something */
> }
>
> /* ... */
>
> func();
>
> is well defined, since the undefined result is not used.
>
> C99 added a special case for main() that makes reaching the closing }
> equivalent to "return 0;". That doesn't affect functions other than
> main().
This presumably makes this (typed into this message) abomination legal:
int func(int parm) {
if(parm > 0) {
printf("I'm positive about things\n");
return -parm;
}
printf("I'm not very positive you know\n");
}
int main(void) {
int x = 27;
...
code to get a value in q
...
if(q > 0)
x = func(y);
else
func(y);
/* x is 27 if q was negative or zero, otherwise it's -q */
....
}
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar
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Re: Baby X "BartC" <bc@freeuk.com> - 2013-08-04 10:29 +0100
Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-04 02:53 -0700
Re: Baby X Keith Thompson <kst-u@mib.org> - 2013-08-04 14:34 -0700
Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-05 04:36 -0700
Re: Baby X Keith Thompson <kst-u@mib.org> - 2013-08-05 08:04 -0700
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Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-06 04:38 -0700
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Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-06 15:17 -0700
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Re: Baby X Ian Collins <ian-news@hotmail.com> - 2013-08-07 13:45 +1200
Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-07 03:22 -0700
Re: Baby X James Kuyper <jameskuyper@verizon.net> - 2013-08-07 06:36 -0400
Re: Baby X Dr Nick <nospam-4@temporary-address.org.uk> - 2013-08-10 20:04 +0100
Re: Baby X Kelsey Bjarnason <kbjarnason@gmail.com> - 2013-08-09 17:28 +0000
Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-09 12:43 -0700
Re: Baby X glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-08-09 20:01 +0000
[OT] Re: Baby X Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-08-09 16:30 -0400
Re: Baby X Keith Thompson <kst-u@mib.org> - 2013-08-09 14:12 -0700
Re: Baby X Dr Nick <nospam-4@temporary-address.org.uk> - 2013-08-10 20:11 +0100
Re: Baby X Robert Wessel <robertwessel2@yahoo.com> - 2013-08-10 14:41 -0500
Re: Baby X James Kuyper <jameskuyper@verizon.net> - 2013-08-10 21:34 -0400
Re: Baby X Dr Nick <nospam-4@temporary-address.org.uk> - 2013-08-11 11:02 +0100
Re: Baby X James Kuyper <jameskuyper@verizon.net> - 2013-08-11 12:54 -0400
Re: Baby X Richard Damon <Richard@Damon-Family.org> - 2013-08-11 13:51 -0400
Re: Baby X James Kuyper <jameskuyper@verizon.net> - 2013-08-11 14:10 -0400
Re: Baby X Richard Damon <Richard@Damon-Family.org> - 2013-08-11 14:43 -0400
Re: Baby X Keith Thompson <kst-u@mib.org> - 2013-08-11 14:03 -0700
Re: Baby X Richard Damon <Richard@Damon-Family.org> - 2013-08-11 17:57 -0400
Re: Baby X Keith Thompson <kst-u@mib.org> - 2013-08-11 18:37 -0700
Re: Baby X glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2013-08-12 04:12 +0000
Re: Baby X Dr Nick <nospam-4@temporary-address.org.uk> - 2013-08-12 07:42 +0100
Re: Baby X Keith Thompson <kst-u@mib.org> - 2013-08-12 09:10 -0700
Re: Baby X Philip Lantz <prl@canterey.us> - 2013-08-17 22:31 -0700
Re: Baby X James Kuyper <jameskuyper@verizon.net> - 2013-08-18 14:50 -0400
Re: Baby X Ike Naar <ike@iceland.freeshell.org> - 2013-08-18 20:15 +0000
Re: Baby X James Kuyper <jameskuyper@verizon.net> - 2013-08-18 16:30 -0400
Re: Baby X Ike Naar <ike@iceland.freeshell.org> - 2013-08-18 21:03 +0000
Re: Baby X Ian Collins <ian-news@hotmail.com> - 2013-08-20 13:09 +1200
Re: Baby X Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2013-08-20 12:24 +0300
Re: Baby X Ben Bacarisse <ben.usenet@bsb.me.uk> - 2013-08-20 13:11 +0100
Re: Baby X Keith Thompson <kst-u@mib.org> - 2013-08-20 08:33 -0700
Re: Baby X Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2013-08-23 11:32 +0300
Re: Baby X Ian Collins <ian-news@hotmail.com> - 2013-08-21 08:01 +1200
Re: Baby X Keith Thompson <kst-u@mib.org> - 2013-08-11 13:57 -0700
Re: Baby X James Kuyper <jameskuyper@verizon.net> - 2013-08-10 21:29 -0400
Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-10 22:04 -0700
Re: Baby X Ike Naar <ike@iceland.freeshell.org> - 2013-08-09 20:16 +0000
Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-09 15:29 -0700
Re: Baby X Ike Naar <ike@iceland.freeshell.org> - 2013-08-10 05:45 +0000
Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-10 03:18 -0700
Re: Baby X Ike Naar <ike@iceland.freeshell.org> - 2013-08-10 17:02 +0000
Re: Baby X Ike Naar <ike@ukato.freeshell.org> - 2013-08-06 21:00 +0000
Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-06 15:07 -0700
Re: Baby X Ian Collins <ian-news@hotmail.com> - 2013-08-05 09:42 +1200
Re: Baby X Roberto Waltman <usenet@rwaltman.com> - 2013-08-04 14:46 -0400
Re: Baby X falk@rahul.net (Edward A. Falk) - 2013-08-15 03:02 +0000
Re: Baby X falk@rahul.net (Edward A. Falk) - 2013-08-15 03:23 +0000
Re: Baby X Malcolm McLean <malcolm.mclean5@btinternet.com> - 2013-08-15 06:09 -0700
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