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[PATCH] manual: Update _DEFAULT_SOURCE.
- From: Rical Jasan <ricaljasan at pacific dot net>
- To: libc-alpha <libc-alpha at sourceware dot org>
- Cc: Joseph Myers <joseph at codesourcery dot com>, Michael Kerrisk <mtk dot manpages at gmail dot com>, Zack Weinberg <zackw at panix dot com>, Carlos O'Donell <carlos at redhat dot com>
- Date: Mon, 19 Feb 2018 04:45:31 -0800
- Subject: [PATCH] manual: Update _DEFAULT_SOURCE.
- Authentication-results: sourceware.org; auth=none
The description of the interplay between feature test macros and
compiler options in the description of _DEFAULT_SOURCE is a little
confusing, and dated, so clarify the situation, and don't assume a
specific value for _DEFAULT_SOURCE.
Also, _DEFAULT_SOURCE is supposed to be defined if none of the C/POSIX
feature test macros are defined, but the condition was lacking a test
for _ISOC11_SOURCE, so that is also addressed.
* include/features.h: Add _ISOC11_SOURCE to test for whether
to define _DEFAULT_SOURCE.
* manual/creature.texi (_DEFAULT_SOURCE): Improve
documentation.
---
include/features.h | 2 +-
manual/creature.texi | 21 ++++++++++++++-------
2 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/include/features.h b/include/features.h
index 137a90b405..d22c32eee6 100644
--- a/include/features.h
+++ b/include/features.h
@@ -214,7 +214,7 @@
define _DEFAULT_SOURCE. */
#if (defined _DEFAULT_SOURCE \
|| (!defined __STRICT_ANSI__ \
- && !defined _ISOC99_SOURCE \
+ && !defined _ISOC99_SOURCE && !defined _ISOC11_SOURCE \
&& !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE \
&& !defined _XOPEN_SOURCE))
# undef _DEFAULT_SOURCE
diff --git a/manual/creature.texi b/manual/creature.texi
index fe7a7790a2..8876b2ab77 100644
--- a/manual/creature.texi
+++ b/manual/creature.texi
@@ -221,13 +221,20 @@ precedence.
If you define this macro, most features are included apart from
X/Open, LFS and GNU extensions: the effect is to enable features from
the 2008 edition of POSIX, as well as certain BSD and SVID features
-without a separate feature test macro to control them. Defining this
-macro, on its own and without using compiler options such as
-@option{-ansi} or @option{-std=c99}, has the same effect as not
-defining any feature test macros; defining it together with other
-feature test macros, or when options such as @option{-ansi} are used,
-enables those features even when the other options would otherwise
-cause them to be disabled.
+without a separate feature test macro to control them.
+
+Be aware that compiler options also affect included features:
+
+@itemize
+@item
+If you use a strict conformance option, features beyond those from the
+compiler's language version will be disabled, though feature test
+macros may be used to enable them.
+
+@item
+Features enabled by compiler options are not overridden by feature
+test macros.
+@end itemize
@end defvr
@defvr Macro _ATFILE_SOURCE
--
2.16.1