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| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: About -lm switch used for linking math.h |
| Date | 2012-01-27 17:04 -0800 |
| Organization | None to speak of |
| Message-ID | <ln4nvg3adl.fsf@nuthaus.mib.org> (permalink) |
| References | (2 earlier) <jfuq77$qrj$1@dont-email.me> <jfur4p$9t$1@dont-email.me> <jfvbdt$1uc$1@dont-email.me> <lnd3a43c56.fsf@nuthaus.mib.org> <9ogttuF8j1U1@mid.individual.net> |
Ian Collins <ian-news@hotmail.com> writes:
> On 01/28/12 01:26 PM, Keith Thompson wrote:
>> Stephen Sprunk<stephen@sprunk.org> writes:
>> [...]
>>> "_Bool" is a hack around the fact there is no way to introduce a new
>>> basic type in a header file. "bool" is what the standard was really
>>> trying to introduce, but that is a typedef to "_Bool" that one gets by
>>> including<stdbool.h>.
>>
>> "bool" is a macro, not a typedef (I'm not sure why).
>>
>>> I'm not sure why "bool" isn't simply a typedef to some existing integer
>>> type, which was common practice prior to _Bool being added to the
>>> language. Perhaps knowing a variable is boolean allows compilers to
>>> make more aggressive optimizations that would be unsafe for other
>>> integer types.
>>
>> _Bool has some characteristics that no other integer type has. For
>> example, converting any scalar type to _Bool yields 0 or 1.
>
> Isn't that the general case converting any larger scalar type to a
> smaller signed one?
Not at all.
Do you mean "smaller *unsigned* type"? That might have been a way
to approach it; make _Bool unsigned, and require it to have only 1
value bit and (CHAR_BIT * sizeof (_Bool) - 1) padding bits. In fact,
I can't think of a way that the current wording is inconsistent
with that model.
But it still couldn't be a typedef for any pre-existing integer
type, since none of the existing types are permitted to have just
one value bit.
Well, it could have been if they hadn't added the conversion rule,
and the requirement that it has lower rank than any other type.
I suspect C++ compatibility was part of the motivation (not that
C *has* to be compatible with C++, but it probably shouldn't be
gratuitously incompatible).
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Will write code for food.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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About -lm switch used for linking math.h Avinash Sonawane <avinash.sonawane1990@gmail.com> - 2012-01-26 13:59 -0800
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-26 14:15 -0800
Re: About -lm switch used for linking math.h James Kuyper <jameskuyper@verizon.net> - 2012-01-26 17:17 -0500
Re: About -lm switch used for linking math.h Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-26 20:54 -0500
Re: About -lm switch used for linking math.h Kaz Kylheku <kaz@kylheku.com> - 2012-01-27 02:12 +0000
Re: About -lm switch used for linking math.h jacob navia <jacob@spamsink.net> - 2012-01-26 23:29 +0100
Re: About -lm switch used for linking math.h Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-01-26 23:09 -0700
Re: About -lm switch used for linking math.h jacob navia <jacob@spamsink.net> - 2012-01-27 08:37 +0100
Re: About -lm switch used for linking math.h gazelle@shell.xmission.com (Kenny McCormack) - 2012-01-27 09:48 +0000
OT:Re: About -lm switch used for linking math.h Kleuske <kleuske@nowhere.net> - 2012-01-27 10:15 +0000
Re: OT:Re: About -lm switch used for linking math.h gazelle@shell.xmission.com (Kenny McCormack) - 2012-01-27 14:43 +0000
Re: OT:Re: About -lm switch used for linking math.h tom st denis <tom@iahu.ca> - 2012-01-27 07:49 -0800
Re: OT:Re: About -lm switch used for linking math.h gazelle@shell.xmission.com (Kenny McCormack) - 2012-01-27 15:55 +0000
Re: OT:Re: About -lm switch used for linking math.h tom st denis <tom@iahu.ca> - 2012-01-27 10:14 -0800
Re: OT:Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-27 11:23 -0800
Re: OT:Re: About -lm switch used for linking math.h Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-01-27 09:42 -0700
Re: OT:Re: About -lm switch used for linking math.h 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-28 14:08 -0800
Re: OT:Re: About -lm switch used for linking math.h Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-02-14 13:14 +0200
Re: About -lm switch used for linking math.h Rui Maciel <rui.maciel@gmail.com> - 2012-01-27 16:56 +0000
Re: About -lm switch used for linking math.h gazelle@shell.xmission.com (Kenny McCormack) - 2012-01-27 17:34 +0000
Re: About -lm switch used for linking math.h Rui Maciel <rui.maciel@gmail.com> - 2012-01-27 17:50 +0000
Re: About -lm switch used for linking math.h Kaz Kylheku <kaz@kylheku.com> - 2012-01-27 17:58 +0000
Re: About -lm switch used for linking math.h tom st denis <tom@iahu.ca> - 2012-01-27 10:15 -0800
Re: About -lm switch used for linking math.h gazelle@shell.xmission.com (Kenny McCormack) - 2012-01-27 19:25 +0000
Re: About -lm switch used for linking math.h Kleuske <kleuske@nowhere.net> - 2012-01-28 18:09 +0000
Re: About -lm switch used for linking math.h jt@toerring.de (Jens Thoms Toerring) - 2012-01-27 21:32 +0000
Re: About -lm switch used for linking math.h "Wolfgang.Draxinger" <Wolfgang.Draxinger@physik.uni-muenchen.de> - 2012-01-27 12:40 +0100
Re: About -lm switch used for linking math.h "BartC" <bc@freeuk.com> - 2012-01-27 12:48 +0000
Re: About -lm switch used for linking math.h Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-27 14:28 +0000
Re: About -lm switch used for linking math.h Kaz Kylheku <kaz@kylheku.com> - 2012-01-27 17:14 +0000
Re: About -lm switch used for linking math.h gazelle@shell.xmission.com (Kenny McCormack) - 2012-01-27 17:34 +0000
Re: About -lm switch used for linking math.h Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-01-27 10:43 -0700
Re: About -lm switch used for linking math.h Stephen Sprunk <stephen@sprunk.org> - 2012-01-27 12:25 -0600
Re: About -lm switch used for linking math.h "BartC" <bc@freeuk.com> - 2012-01-27 18:41 +0000
Re: About -lm switch used for linking math.h James Kuyper <jameskuyper@verizon.net> - 2012-01-27 13:45 -0500
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-27 11:29 -0800
Re: About -lm switch used for linking math.h Jens Gustedt <jens.gustedt@loria.fr> - 2012-01-27 22:35 +0100
Re: About -lm switch used for linking math.h Stephen Sprunk <stephen@sprunk.org> - 2012-01-27 17:19 -0600
Re: About -lm switch used for linking math.h James Kuyper <jameskuyper@verizon.net> - 2012-01-27 19:22 -0500
Re: About -lm switch used for linking math.h Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-31 23:32 -0800
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-27 16:26 -0800
Re: About -lm switch used for linking math.h Ian Collins <ian-news@hotmail.com> - 2012-01-28 13:30 +1300
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-27 17:04 -0800
Re: About -lm switch used for linking math.h Ian Collins <ian-news@hotmail.com> - 2012-01-28 14:10 +1300
Re: About -lm switch used for linking math.h Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-27 21:06 -0500
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-27 20:09 -0800
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-27 20:15 -0800
Re: About -lm switch used for linking math.h Stephen Sprunk <stephen@sprunk.org> - 2012-01-27 23:03 -0600
Re: About -lm switch used for linking math.h Ian Collins <ian-news@hotmail.com> - 2012-01-28 19:10 +1300
Re: About -lm switch used for linking math.h Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-01-28 04:28 -0800
Re: About -lm switch used for linking math.h Stephen Sprunk <stephen@sprunk.org> - 2012-01-28 15:25 -0600
Re: About -lm switch used for linking math.h Ian Collins <ian-news@hotmail.com> - 2012-01-29 11:39 +1300
Re: About -lm switch used for linking math.h Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-29 09:53 -0800
Re: About -lm switch used for linking math.h Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-02-03 10:39 +0000
Re: About -lm switch used for linking math.h Joshua Maurice <joshuamaurice@gmail.com> - 2012-02-01 16:42 -0800
Re: About -lm switch used for linking math.h jgk@panix.com (Joe keane) - 2012-02-02 01:29 +0000
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-28 15:22 -0800
Re: About -lm switch used for linking math.h Stephen Sprunk <stephen@sprunk.org> - 2012-01-29 16:52 -0600
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-30 02:04 -0800
Re: About -lm switch used for linking math.h Ike Naar <ike@iceland.freeshell.org> - 2012-01-30 10:22 +0000
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-30 02:36 -0800
Re: About -lm switch used for linking math.h Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-02-14 13:33 +0200
Re: About -lm switch used for linking math.h Ike Naar <ike@iceland.freeshell.org> - 2012-02-14 23:48 +0000
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-02-14 16:35 -0800
Re: About -lm switch used for linking math.h Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-02-22 02:44 +0200
Re: About -lm switch used for linking math.h Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-01-30 04:30 -0800
Re: About -lm switch used for linking math.h Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-30 14:36 +0000
Re: About -lm switch used for linking math.h Tim Rentsch <txr@alumni.caltech.edu> - 2012-01-31 23:50 -0800
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-28 15:29 -0800
Re: About -lm switch used for linking math.h Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-01-29 09:11 -0800
Re: About -lm switch used for linking math.h "BartC" <bc@freeuk.com> - 2012-01-29 17:49 +0000
Re: About -lm switch used for linking math.h Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-01-29 10:07 -0800
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-29 14:24 -0800
Re: About -lm switch used for linking math.h Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-29 09:43 -0800
Re: About -lm switch used for linking math.h Keith Thompson <kst-u@mib.org> - 2012-01-27 16:54 -0800
Re: About -lm switch used for linking math.h Kaz Kylheku <kaz@kylheku.com> - 2012-01-28 01:09 +0000
Re: About -lm switch used for linking math.h Ian Collins <ian-news@hotmail.com> - 2012-01-28 14:20 +1300
Re: About -lm switch used for linking math.h Azazel <azazel@remove.azazel.net> - 2012-01-30 17:40 -0600
Re: About -lm switch used for linking math.h Kaz Kylheku <kaz@kylheku.com> - 2012-01-31 00:05 +0000
Re: About -lm switch used for linking math.h jgk@panix.com (Joe keane) - 2012-01-27 20:03 +0000
Re: About -lm switch used for linking math.h Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-01-27 12:26 -0800
Re: About -lm switch used for linking math.h Ian Collins <ian-news@hotmail.com> - 2012-01-28 10:24 +1300
Re: About -lm switch used for linking math.h "BartC" <bc@freeuk.com> - 2012-01-27 21:32 +0000
Re: About -lm switch used for linking math.h James Kuyper <jameskuyper@verizon.net> - 2012-01-27 16:39 -0500
Re: About -lm switch used for linking math.h Robert Wessel <robertwessel2@yahoo.com> - 2012-01-27 23:24 -0600
Re: About -lm switch used for linking math.h Ian Collins <ian-news@hotmail.com> - 2012-01-28 20:38 +1300
Re: About -lm switch used for linking math.h Robert Wessel <robertwessel2@yahoo.com> - 2012-01-28 02:17 -0600
Re: About -lm switch used for linking math.h Richard Damon <news.x.richarddamon@xoxy.net> - 2012-01-28 14:07 -0500
Re: About -lm switch used for linking math.h Robert Wessel <robertwessel2@yahoo.com> - 2012-01-28 15:07 -0600
Re: About -lm switch used for linking math.h jgk@panix.com (Joe keane) - 2012-01-28 21:09 +0000
Re: About -lm switch used for linking math.h Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-01-27 21:39 -0700
Re: About -lm switch used for linking math.h Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-28 11:21 +0000
Re: About -lm switch used for linking math.h Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-01-28 17:51 -0700
Re: About -lm switch used for linking math.h Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-29 02:03 +0000
Re: About -lm switch used for linking math.h Kaz Kylheku <kaz@kylheku.com> - 2012-01-28 18:58 +0000
Re: About -lm switch used for linking math.h jacob navia <jacob@spamsink.net> - 2012-01-28 20:48 +0100
Re: About -lm switch used for linking math.h Robert Wessel <robertwessel2@yahoo.com> - 2012-01-28 22:54 -0600
Re: About -lm switch used for linking math.h jgk@panix.com (Joe keane) - 2012-01-29 21:42 +0000
Re: About -lm switch used for linking math.h Robert Wessel <robertwessel2@yahoo.com> - 2012-01-30 00:14 -0600
Re: About -lm switch used for linking math.h Stephen Sprunk <stephen@sprunk.org> - 2012-01-27 11:12 -0600
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