Re: POSIX_C_SOURCE

From: Matthew Dillon (dillon_at_apollo.backplane.com)
Date: 08/30/03

  • Next message: Erik Trulsson: "Re: POSIX_C_SOURCE" 
    Date: Sat, 30 Aug 2003 10:30:01 -0700 (PDT)
To: Erik Trulsson <ertr1013@student.uu.se>

        This is precisely what I did a few days ago in DragonFly. The warnings
        were getting annoying.

                                            -Matt
                                            Matthew Dillon
                                            <dillon@backplane.com>

    :
    :On Sat, Aug 30, 2003 at 12:49:15PM -0400, Garrett Wollman wrote:
    :> In article <20030830161813.GA28890@twisted.net> you write:
    :>
    :> >Any chance that someone will finally commit the fixes to prevent the
    :> >POSIX_C_SOURCE warnings from showing up? I saw a number of posts on this
    :> >topic, but it still seems like it's not "officially committed"
    :>
    :> >/usr/include/sys/cdefs.h:273: warning: `_POSIX_C_SOURCE' is not defined
    :> >/usr/include/sys/cdefs.h:279: warning: `_POSIX_C_SOURCE' is not defined
    :>
    :> The warnings are wrong,[1] so you should probably ask the GCC people
    :> about that.
    :
    :The warnings are not wrong (see below), but anyway, since -stable uses
    :the "ancient" GCC 2.95.4, the GCC people are not likely to
    :give a damn in either case. They usually don't care about the older
    :releases.
    :
    :>
    :> -GAWollman
    :>
    :> [1] That is to say, any identifier used in a preprocessor expression
    :> (after macro expansion) is defined to have a value of zero, and GCC
    :> should not be complaining about this.
    :
    :The code is correct, which is why GCC only gives a warning and not an
    :error. Code looking like that are usually an indication of a
    :programmer error though, so GCC is perfectly right in warning about
    :it. This is similar to the compiler warning about unused variables,
    :which isn't a bug either but often indicates a programmer mistake.
    :
    :To make gcc shut up, you can apply the following patch to cdefs.h
    :which makes the warnings go away, without changing the semantics of the
    :include file in any way.
    :
    :
    :Index: cdefs.h
    :===================================================================
    :RCS file: /ncvs/src/sys/sys/cdefs.h,v
    :retrieving revision 1.28.2.8
    :diff -u -r1.28.2.8 cdefs.h
    :--- cdefs.h 18 Sep 2002 04:05:13 -0000 1.28.2.8
    :+++ cdefs.h 29 Jan 2003 21:23:30 -0000
    :@@ -269,6 +269,8 @@
    : * Our macros begin with two underscores to avoid namespace screwage.
    : */
    :
    :+#ifdef _POSIX_C_SOURCE
    :+
    : /* Deal with IEEE Std. 1003.1-1990, in which _POSIX_C_SOURCE == 1. */
    : #if _POSIX_C_SOURCE == 1
    : #undef _POSIX_C_SOURCE /* Probably illegal, but beyond caring now. */
    :@@ -280,6 +282,8 @@
    : #undef _POSIX_C_SOURCE
    : #define _POSIX_C_SOURCE 199209
    : #endif
    :+
    :+#endif /* _POSIX_C_SOURCE */
    :
    : /* Deal with various X/Open Portability Guides and Single UNIX Spec. */
    : #ifdef _XOPEN_SOURCE
    :
    :
    :
    :
    :--
    :<Insert your favourite quote here.>
    :Erik Trulsson
    :ertr1013@student.uu.se
    :_______________________________________________
    :freebsd-stable@freebsd.org mailing list
    :http://lists.freebsd.org/mailman/listinfo/freebsd-stable
    :To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org"
    :

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  • Next message: Erik Trulsson: "Re: POSIX_C_SOURCE"

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