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| From | David Brown <david.brown@hesbynett.no> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: To include or not to include |
| Date | 2016-09-23 12:43 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <ns310l$bj5$1@dont-email.me> (permalink) |
| References | <ns2tkb$p0$1@dont-email.me> |
On 23/09/16 11:45, James Harris wrote: > I often have at the top of a C source file, which I'll call F, an > include for its corresponding header: > > #include "F.h" > > After that come the various includes I need for the .c code that follows. > > In many cases the .c and the .h include some of the same files. They > might both pull in stdio.h or string.h, for example. > > Of course, I could omit from F.c at least some of the headers which F.h > includes. But I tend to take the approach of including in the .c all > those the .c code needs. > > Assuming either approach is just as valid, which is the best style or is > one more idiomatic than the other? > > > As an aside, in F.c I include F.h so that the compiler can check that > function definitions (in F.c) match function declarations (in F.h). So, > if it's relevant, I guess I tend to use includes as a policy rather than > as a mechanism for managing other includes. > I prefer the following rules for includes: 1. F.c should include F.h, to make sure that function definitions in F.c and function declarations in F.h match. 2. I make sure that any functions or file-level variables in F.c are either defined "static" in F.c, or they are declared "extern" in F.h and have matching definitions in F.c. 3. Header F.h should include all the headers it needs in order to be complete. If G.c includes F.h, it should not have to include anything else before or after it. So if F.h declares a function that takes a uint32_t, then F.h must include stdint.h. 4. Headers should have guards so that you can safely include them many times. 5. It should be possible to include the headers in any order (this mostly follows from 3 and 4), both in c and h files. 6. If F.c uses something from G.h, then it should include G.h - even if F.h already includes G.h. This is for clarity and self-documentation in the code. (Since this is not required for the correctness of the code, I guess you can count it as "policy rather than mechanism".) Things can get a lot more complicated with multiple directories, include paths, combined headers, etc. But I think they are good rules to start with.
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To include or not to include James Harris <james.harris.1@gmail.com> - 2016-09-23 10:45 +0100
Re: To include or not to include David Brown <david.brown@hesbynett.no> - 2016-09-23 12:43 +0200
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-23 12:17 +0100
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-23 13:32 +0100
Re: To include or not to include David Brown <david.brown@hesbynett.no> - 2016-09-23 14:57 +0200
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-24 20:34 +0100
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-24 23:55 +0100
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-25 01:43 +0100
Re: To include or not to include Ian Collins <ian-news@hotmail.com> - 2016-09-25 14:38 +1300
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-25 11:42 +0100
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-25 11:58 +0100
Re: To include or not to include James Harris <james.harris.1@gmail.com> - 2016-09-25 14:06 +0100
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-25 15:15 +0100
Re: To include or not to include Reinhardt Behm <rbehm@hushmail.com> - 2016-09-25 23:33 +0800
Re: To include or not to include Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-09-25 10:04 -0600
Re: To include or not to include Reinhardt Behm <rbehm@hushmail.com> - 2016-09-26 00:21 +0800
Re: To include or not to include "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-25 13:17 -0400
Re: To include or not to include James Harris <james.harris.1@gmail.com> - 2016-09-26 00:18 +0100
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-26 17:55 +0100
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-26 20:07 +0100
Re: To include or not to include supercat@casperkitty.com - 2016-09-26 12:13 -0700
Re: To include or not to include James Harris <james.harris.1@gmail.com> - 2016-09-27 01:25 +0100
Re: To include or not to include supercat@casperkitty.com - 2016-09-26 18:05 -0700
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-27 14:27 +0100
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-27 14:49 +0100
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-27 15:15 +0100
Re: To include or not to include Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-27 07:42 -0700
Re: To include or not to include Keith Thompson <kst-u@mib.org> - 2016-09-27 09:30 -0700
Re: To include or not to include Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-27 10:06 -0700
Re: To include or not to include supercat@casperkitty.com - 2016-09-27 08:12 -0700
Re: To include or not to include Tim Rentsch <txr@alumni.caltech.edu> - 2016-09-28 10:46 -0700
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-27 17:55 +0100
Re: To include or not to include supercat@casperkitty.com - 2016-09-27 10:19 -0700
Re: To include or not to include Keith Thompson <kst-u@mib.org> - 2016-09-27 11:42 -0700
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-27 19:57 +0100
Re: To include or not to include Keith Thompson <kst-u@mib.org> - 2016-09-27 12:38 -0700
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-27 21:00 +0100
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-28 01:50 +0100
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-28 10:55 +0100
Re: To include or not to include Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-27 13:33 -0700
Re: To include or not to include Ike Naar <ike@iceland.freeshell.org> - 2016-09-28 19:13 +0000
Re: To include or not to include supercat@casperkitty.com - 2016-09-27 12:38 -0700
Re: To include or not to include James Harris <james.harris.1@gmail.com> - 2016-09-27 20:57 +0100
Re: To include or not to include supercat@casperkitty.com - 2016-09-27 07:25 -0700
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-28 00:28 +0100
Re: To include or not to include supercat@casperkitty.com - 2016-09-30 07:53 -0700
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-30 16:06 +0100
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-27 13:53 +0100
Re: To include or not to include James Harris <james.harris.1@gmail.com> - 2016-09-30 19:46 +0100
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-30 20:27 +0100
Re: To include or not to include Reinhardt Behm <rbehm@hushmail.com> - 2016-09-25 23:27 +0800
Re: To include or not to include Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-25 11:38 -0400
Re: To include or not to include Reinhardt Behm <rbehm@hushmail.com> - 2016-09-25 23:40 +0800
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-25 15:06 +0100
Re: To include or not to include Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-25 11:49 -0400
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-25 18:05 +0100
Re: To include or not to include Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-25 16:42 -0400
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-25 21:53 +0100
Re: To include or not to include Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-25 17:57 -0400
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-25 21:20 +0100
Re: To include or not to include BartC <bc@freeuk.com> - 2016-09-25 21:49 +0100
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-26 00:40 +0100
Re: To include or not to include David Brown <david.brown@hesbynett.no> - 2016-09-23 14:56 +0200
Re: To include or not to include Richard Heathfield <rjh@cpax.org.uk> - 2016-09-23 13:31 +0100
Re: To include or not to include James Harris <james.harris.1@gmail.com> - 2016-09-23 13:52 +0100
Re: To include or not to include Richard Heathfield <rjh@cpax.org.uk> - 2016-09-23 14:35 +0100
Re: To include or not to include Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-23 18:55 +0100
Re: To include or not to include Richard Heathfield <rjh@cpax.org.uk> - 2016-09-23 20:33 +0100
Re: To include or not to include Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-09-23 08:22 -0600
Re: To include or not to include Richard Damon <Richard@Damon-Family.org> - 2016-09-23 11:37 -0400
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