Article View: comp.std.c
Article #5676Re: Re: __STDC__, _POSIX_SOURCE, etc.
From: Doug Gwyn
Date: Wed, 25 Jan 1989 21:03
Date: Wed, 25 Jan 1989 21:03
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In article <12040009@hpfcdc.HP.COM> rml@hpfcdc.HP.COM (Bob Lenk) writes: >The stated benefit is that the program does not have to be modified to >#define _POSIX_SOURCE, since _POSIX_VERSION is defined by the >implementation. In practice this does not seem to be a real benefit, >since it applies only to programs that already #include <unistd.h> >before #including any other header (or at least any ANSI C related >header); I doubt this covers any large number of existing programs. >Any other program requires a source change, which seems like no benefit >over adding #define _POSIX_SOURCE. I believe the reasoning was that technically <unistd.h> was going to have to be included by almost any 1003.1-conformant application, and that the automatic approach that takes care of the additional name- space-in-standard-header issue would be less trouble than requiring yet a second edit to the application as apparently required by the _POSIX_SOURCE invention. I will admit that finding "#define _POSIX_SOURCE" as the first line of a source file might serve as a useful indication that somebody has "POSIXized" the source. If it is generally going to be the case that the POSIX compilation environment predefines _POSIX_SOURCE then that is not a good argument. I like the suggestion that 1003.1 publish a clarification of this whole business. If there are some non-required but generally agreed techniques for the definition and use of these symbols, perhaps it would be appropriate to try to steer vendors along the same path also.
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!lll-winken!ncis.llnl.gov!helios.ee.lbl.gov!pasteur!ames!haven!adm!smoke!gwyn From: gwyn@smoke.BRL.MIL (Doug Gwyn ) Newsgroups: comp.std.c Subject: Re: Re: __STDC__, _POSIX_SOURCE, etc. Message-ID: <9500@smoke.BRL.MIL> Date: 25 Jan 89 21:03:39 GMT References: <9458@smoke.BRL.MIL> <12040009@hpfcdc.HP.COM> Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) Organization: Ballistic Research Lab (BRL), APG, MD. Lines: 26