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Fix features.h for -Wundef (bug 19212)
- From: Joseph Myers <joseph at codesourcery dot com>
- To: <libc-alpha at sourceware dot org>
- Date: Thu, 5 Nov 2015 18:25:19 +0000
- Subject: Fix features.h for -Wundef (bug 19212)
- Authentication-results: sourceware.org; auth=none
features.h is not clean with -Wundef (for the installed header, of
course this only appears with -Wsystem-headers). In ISO C standards
modes, you get a series of warnings / errors relating to
_POSIX_C_SOURCE and _XOPEN_SOURCE not being defined when tested in
#if; this shows up if adding a testcase that builds in a strict C
standards mode and uses #undef _GNU_SOURCE to avoid the default
_GNU_SOURCE from libc-symbols.h. This patch changes the relevant #if
conditionals to avoid these warnings / errors.
Tested for x86_64 and x86 (testsuite, and that installed shared
libraries are unchanged by the patch).
2015-11-05 Joseph Myers <joseph@codesourcery.com>
[BZ #19212]
* include/features.h [(_XOPEN_SOURCE - 0) >= 500]: Change
conditional to [defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >=
500].
[_POSIX_C_SOURCE >= 1]: Change conditional to [defined
_POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1].
[(_POSIX_C_SOURCE - 0) >= 199309L]: Change conditional to [defined
_POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199309L].
[(_POSIX_C_SOURCE - 0) >= 199506L]: Change conditional to [defined
_POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199506L].
[(_POSIX_C_SOURCE - 0) >= 200112L]: Change conditional to [defined
_POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200112L].
[(_POSIX_C_SOURCE - 0) >= 200809L]: Change conditional to [defined
_POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200809L].
diff --git a/include/features.h b/include/features.h
index bb80610..774afdd 100644
--- a/include/features.h
+++ b/include/features.h
@@ -224,8 +224,9 @@
# undef _POSIX_C_SOURCE
# define _POSIX_C_SOURCE 200809L
#endif
-#if ((!defined __STRICT_ANSI__ || (_XOPEN_SOURCE - 0) >= 500) && \
- !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
+#if ((!defined __STRICT_ANSI__ \
+ || (defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >= 500)) \
+ && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
# define _POSIX_SOURCE 1
# if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
# define _POSIX_C_SOURCE 2
@@ -239,7 +240,9 @@
# define __USE_POSIX_IMPLICITLY 1
#endif
-#if defined _POSIX_SOURCE || _POSIX_C_SOURCE >= 1 || defined _XOPEN_SOURCE
+#if (defined _POSIX_SOURCE \
+ || (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1) \
+ || defined _XOPEN_SOURCE)
# define __USE_POSIX 1
#endif
@@ -247,15 +250,15 @@
# define __USE_POSIX2 1
#endif
-#if (_POSIX_C_SOURCE - 0) >= 199309L
+#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199309L
# define __USE_POSIX199309 1
#endif
-#if (_POSIX_C_SOURCE - 0) >= 199506L
+#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199506L
# define __USE_POSIX199506 1
#endif
-#if (_POSIX_C_SOURCE - 0) >= 200112L
+#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200112L
# define __USE_XOPEN2K 1
# undef __USE_ISOC95
# define __USE_ISOC95 1
@@ -263,7 +266,7 @@
# define __USE_ISOC99 1
#endif
-#if (_POSIX_C_SOURCE - 0) >= 200809L
+#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200809L
# define __USE_XOPEN2K8 1
# undef _ATFILE_SOURCE
# define _ATFILE_SOURCE 1
--
Joseph S. Myers
joseph@codesourcery.com