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Re: what is the best way

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Les Cargill <lcargill99@comcast.com> writes:
[...]
> - Have this basic structure:
>
> thing.h:
>
> #ifndef _THING_H_
> #define _THING_H_ 1
> ...
> #endif
>
> guarding all header files.
[...]

Identifiers starting with an underscore and an uppercase letter
(or with two underscores) are reserved to the implementation for
any use; in other words, you should never use such identifiers in
your own code.

Just use this:

#ifndef THING_H
#define THING_H
...
#endif /* THING_H */

(or some scheme that maps reasonably well from file names to
identifiers without stepping on anything that's reserved).

Note that identifiers starting with E and either a digit or an
uppercase letter may be used for implementation-defined macros
in <errno.h>, so a header name that happens to start with E might
cause problems.  One way to avoid that is:

#ifndef H_THING
#define H_THING
...
#endif /* H_THING */

It's not terribly likely that an implementation is going to use
_THING_H_ or EXTRA_FOO for its own purposes, so you can very likely
get away with using such identifiers yourself, but if you avoid
reserved identifiers you have one less thing to worry about.

-- 
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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what is the best way Andre <pas.mois@ailleur.be> - 2012-11-27 16:19 +0100
  Re: what is the best way Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-27 15:35 +0000
  Re: what is the best way Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-27 08:59 -0800
  Re: what is the best way James Kuyper <jameskuyper@verizon.net> - 2012-11-27 13:14 -0500
    Re: what is the best way Ian Collins <ian-news@hotmail.com> - 2012-11-28 08:43 +1300
      Re: what is the best way James Kuyper <jameskuyper@verizon.net> - 2012-11-27 15:02 -0500
        Re: what is the best way Ian Collins <ian-news@hotmail.com> - 2012-11-28 09:29 +1300
  Re: what is the best way Les Cargill <lcargill99@comcast.com> - 2012-11-27 12:48 -0600
    Re: what is the best way Ian Collins <ian-news@hotmail.com> - 2012-11-28 08:56 +1300
      Re: what is the best way Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-11-27 22:19 +0000
        Re: what is the best way Les Cargill <lcargill99@comcast.com> - 2012-11-27 18:21 -0600
          Re: what is the best way Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-28 05:08 -0800
            Re: what is the best way Les Cargill <lcargill99@comcast.com> - 2012-11-28 12:43 -0600
      Re: what is the best way Les Cargill <lcargill99@comcast.com> - 2012-11-27 18:15 -0600
        Re: what is the best way Ian Collins <ian-news@hotmail.com> - 2012-11-28 14:21 +1300
          Re: what is the best way Les Cargill <lcargill99@comcast.com> - 2012-11-27 20:06 -0600
            Re: what is the best way Ian Collins <ian-news@hotmail.com> - 2012-11-28 15:21 +1300
              Re: what is the best way Les Cargill <lcargill99@comcast.com> - 2012-11-27 20:31 -0600
              Re: what is the best way glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-28 04:00 +0000
              Re: what is the best way Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-28 05:17 -0800
                Re: what is the best way Ian Collins <ian-news@hotmail.com> - 2012-11-29 08:30 +1300
                Re: what is the best way Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-29 05:47 -0800
                Re: what is the best way Ian Collins <ian-news@hotmail.com> - 2012-11-30 07:37 +1300
                Re: what is the best way Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-11-29 11:35 -0800
    Re: what is the best way Keith Thompson <kst-u@mib.org> - 2012-11-27 17:25 -0800
      Re: what is the best way Les Cargill <lcargill99@comcast.com> - 2012-11-27 20:15 -0600
      Re: what is the best way pete <pfiland@mindspring.com> - 2012-11-27 23:48 -0500
    Re: what is the best way Sergio Durigan Junior <sergiodj@riseup.net> - 2012-11-28 03:06 -0200
      Re: what is the best way pete <pfiland@mindspring.com> - 2012-11-28 01:35 -0500
  Re: what is the best way pete <pfiland@mindspring.com> - 2012-11-28 00:13 -0500

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