Date: Fri, 12 Feb 2016 19:36:41 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Bruce Evans <brde@optusnet.com.au> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r295561 - in head: include sys/mips/include sys/powerpc/include sys/sparc64/include sys/sys sys/x86/include Message-ID: <20160212173641.GV91220@kib.kiev.ua> In-Reply-To: <20160213021939.S1340@besplex.bde.org> References: <201602120738.u1C7cKpq093956@repo.freebsd.org> <20160212232717.P894@besplex.bde.org> <20160212143630.GS91220@kib.kiev.ua> <20160213021939.S1340@besplex.bde.org>
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On Sat, Feb 13, 2016 at 03:56:42AM +1100, Bruce Evans wrote: > Our Standard C namespace is a subset of the POSIX namespace. Most > Standard C headers are (were) careful about this. There aren't many > Standard C headers or versions of Standard C or large variations in the > versions, so this is relatively easy to do. > > We also attempt to use POSIX visibility ifdefs. This is not done so > carefully, and has more bugs due to more variations. But <signal.h> > does it fairly carefully. It has ifdefs for XSI, POSIX >= 2001, > any-POSIX (this is now very broken by unconditional declarations for > pthreads), POSIX >= 1995 (realtime POSIX stuff which I think was > standardized in POSIX.4 (.1b?) a couple of years before 1995, but we > don't have ifdefs for that), POSIX >= 2008 (psignal). That is just > in the top-level header. Almost half of that is only under XSI or > BSD, and it is quite likely that some newer or older POSIX or XSI > things are under the wrong ifdefed but are usually visible because > everything is visible by default. sys/signal.h has ifdefs for > POSIX >= 1993, more-delicate version ifdefs for XSI and POSIX <= 2001. > Most of the POSIX >= 1993 ifdefs are for realtime POSIX stuff. An > enormous number of definitions for things like trap codes for FP errors > are misplaced under the POSIX >= 1993 || XSI ifdef. These weren't in > POSIX.1-2006. This contrasts with the fine-grained ifdefs for signal > numbers. > > I find the ifdefs useful for seeing when POSIX introduced a feature > but not for actual use to compile under an old standard. So you are about the ANSI C & non-POSIX compilation environment ? Do you mean the following: diff --git a/include/signal.h b/include/signal.h index 33be55c..31cded7 100644 --- a/include/signal.h +++ b/include/signal.h @@ -36,8 +36,10 @@ #include <sys/cdefs.h> #include <sys/_types.h> #include <sys/signal.h> +#if __POSIX_VISIBLE || __XSI_VISIBLE #include <machine/ucontext.h> #include <sys/_ucontext.h> +#endif #if __BSD_VISIBLE /* I can change #if __POSIX_VISIBLE to some version cap, if you prefer.
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