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| From | James Kuyper <jameskuyper@verizon.net> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: About -lm switch used for linking math.h |
| Date | 2012-01-26 17:17 -0500 |
| Organization | A noiseless patient Spider |
| Message-ID | <jfsjdl$1s8$1@dont-email.me> (permalink) |
| References | <33220336.277.1327615195035.JavaMail.geo-discussion-forums@prnc5> |
On 01/26/2012 04:59 PM, Avinash Sonawane wrote: > Sir, > I am using gcc 4.6.1. > I have few questions regarding -lm switch. Please kindly guide me for the same. > > 1) Why I need to use -lm flag for math.h even if I had declared the > #include <math.h> in the code? #include <math.h> tells the compiler which library header to insert into your program when compiling. -lm tells the linker which library to search when linking your compiled program. A compiler could connect the two, but most of the ones I'm familiar with don't. > 2) If it's all about linking the library then why I don't have to do > the same thing with stdio.h too? By convention dating back to the early days of C, most of the C standard library is often stored in one library file, except for the part described by <math.h>, which is stored in a different one. This approach became conventional because, especially at that time, most programs made no use of the math library, and adding all of those functions to the linker's search would significantly slowed down linkage. This is far less of an issue now than it used to be, but some habits, once started, are hard to change. > 3) Or we have to add the -l'library' switch for every library excluding stdio.h? No. > 4) In case if the -l'library' switch is used for some specific > libraries only then please direct me to the complete list of such > libraries. Any such list could, in principle, be different for different compilers, and there's no way it could be complete - there's millions of libraries out there. The best you can hope for is a list of C standard library parts. However, for most systems I've familiar with, <math.h> is the only part of the C standard library that has it's own separate library file.
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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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