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GNU C Library master sources branch master updated. glibc-2.24-456-gc030737
- From: zack at sourceware dot org
- To: glibc-cvs at sourceware dot org
- Date: 8 Dec 2016 20:47:38 -0000
- Subject: GNU C Library master sources branch master updated. glibc-2.24-456-gc030737
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http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=c03073774f915fe7841c2b551fe304544143470f
commit c03073774f915fe7841c2b551fe304544143470f
Author: Zack Weinberg <zackw@panix.com>
Date: Tue Dec 6 10:14:42 2016 -0500
Make _REENTRANT and _THREAD_SAFE aliases for _POSIX_C_SOURCE=199506L.
For many years, the only effect of these macros has been to make
unistd.h declare getlogin_r. _POSIX_C_SOURCE >= 199506L also causes
this function to be declared. However, people who don't carefully
read all the headers might be confused into thinking they need to
define _REENTRANT for any threaded code (as was indeed the case a long
time ago).
Therefore, remove __USE_REENTRANT, and make _REENTRANT and _THREAD_SAFE
into synonyms for _POSIX_C_SOURCE=199506L. This will only affect
programs that don't select a higher conformance level some other way.
For instance, -std=c89 -D_REENTRANT will see a change in visible
declarations, but -std=c99 -D_POSIX_C_SOURCE=200809L -D_REENTRANT won't,
and -D_REENTRANT all by itself also won't, because _DEFAULT_SOURCE
implies _POSIX_C_SOURCE > 199506.
* include/features.h: Remove __USE_REENTRANT. Treat _REENTRANT
and _THREAD_SAFE the same as _POSIX_C_SOURCE=199506L, if a higher
POSIX conformance level has not been selected by other macros.
* NEWS, manual/creature.texi: Document this change.
* posix/unistd.h, posix/bits/unistd.h: Don't check __USE_REENTRANT.
* include/libc-symbols.h: Don't define _REENTRANT.
* scripts/check-installed-headers.sh: Don't undefine _REENTRANT.
diff --git a/NEWS b/NEWS
index 922a500..4fe8886 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,19 @@ Version 2.25
from that TS. Note that most features from that TS are not supported by
the GNU C Library.
+* The nonstandard feature selection macros _REENTRANT and _THREAD_SAFE are
+ now treated as compatibility synonyms for _POSIX_C_SOURCE=199506L.
+ Since the GNU C Library defaults to a much newer revision of POSIX, this
+ will only affect programs that specifically request an old conformance
+ mode. For instance, a program compiled with -std=c89 -D_REENTRANT will
+ see a change in the visible declarations, but a program compiled with
+ just -D_REENTRANT, or -std=c99 -D_POSIX_C_SOURCE=200809L -D_REENTRANT,
+ will not.
+
+ Some C libraries once required _REENTRANT and/or _THREAD_SAFE to be
+ defined by all multithreaded code, but glibc has not required this for
+ many years.
+
* The inclusion of <sys/sysmacros.h> by <sys/types.h> is deprecated. This
means that in a future release, the macros â??majorâ??, â??minorâ??, and â??makedevâ??
will only be available from <sys/sysmacros.h>.
diff --git a/include/features.h b/include/features.h
index 650d4c5..4d8bda1 100644
--- a/include/features.h
+++ b/include/features.h
@@ -24,10 +24,13 @@
__STRICT_ANSI__ ISO Standard C.
_ISOC99_SOURCE Extensions to ISO C89 from ISO C99.
_ISOC11_SOURCE Extensions to ISO C99 from ISO C11.
- __STDC_WANT_LIB_EXT2__ Extensions to ISO C99 from TR 27431-2:2010.
- __STDC_WANT_IEC_60559_BFP_EXT__ Extensions to ISO C11 from TS 18661-1:2014.
- __STDC_WANT_IEC_60559_FUNCS_EXT__ Extensions to ISO C11 from
- TS 18661-4:2015.
+ __STDC_WANT_LIB_EXT2__
+ Extensions to ISO C99 from TR 27431-2:2010.
+ __STDC_WANT_IEC_60559_BFP_EXT__
+ Extensions to ISO C11 from TS 18661-1:2014.
+ __STDC_WANT_IEC_60559_FUNCS_EXT__
+ Extensions to ISO C11 from TS 18661-4:2015.
+
_POSIX_SOURCE IEEE Std 1003.1.
_POSIX_C_SOURCE If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
if >=199309L, add IEEE Std 1003.1b-1993;
@@ -45,10 +48,12 @@
_GNU_SOURCE All of the above, plus GNU extensions.
_DEFAULT_SOURCE The default set of features (taking precedence over
__STRICT_ANSI__).
- _REENTRANT Select additionally reentrant object.
- _THREAD_SAFE Same as _REENTRANT, often used by other systems.
- _FORTIFY_SOURCE If set to numeric value > 0 additional security
- measures are defined, according to level.
+
+ _FORTIFY_SOURCE Add security hardening to many library functions.
+ Set to 1 or 2; 2 performs stricter checks than 1.
+
+ _REENTRANT, _THREAD_SAFE
+ Obsolete; equivalent to _POSIX_C_SOURCE=199506L.
The `-ansi' switch to the GNU C compiler, and standards conformance
options such as `-std=c99', define __STRICT_ANSI__. If none of
@@ -86,7 +91,6 @@
__USE_MISC Define things from 4.3BSD or System V Unix.
__USE_ATFILE Define *at interfaces and AT_* constants for them.
__USE_GNU Define GNU extensions.
- __USE_REENTRANT Define reentrant/thread-safe *_r functions.
__USE_FORTIFY_LEVEL Additional security measures used, according to level.
The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
@@ -130,7 +134,6 @@
#undef __USE_MISC
#undef __USE_ATFILE
#undef __USE_GNU
-#undef __USE_REENTRANT
#undef __USE_FORTIFY_LEVEL
#undef __KERNEL_STRICT_NAMES
@@ -253,6 +256,7 @@
# undef _POSIX_C_SOURCE
# define _POSIX_C_SOURCE 200809L
#endif
+
#if ((!defined __STRICT_ANSI__ \
|| (defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >= 500)) \
&& !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
@@ -269,6 +273,19 @@
# define __USE_POSIX_IMPLICITLY 1
#endif
+/* Some C libraries once required _REENTRANT and/or _THREAD_SAFE to be
+ defined in all multithreaded code. GNU libc has not required this
+ for many years. We now treat them as compatibility synonyms for
+ _POSIX_C_SOURCE=199506L, which is the earliest level of POSIX with
+ comprehensive support for multithreaded code. Using them never
+ lowers the selected level of POSIX conformance, only raises it. */
+#if ((!defined _POSIX_C_SOURCE || (_POSIX_C_SOURCE - 0) < 199506L) \
+ && (defined _REENTRANT || defined _THREAD_SAFE))
+# define _POSIX_SOURCE 1
+# undef _POSIX_C_SOURCE
+# define _POSIX_C_SOURCE 199506L
+#endif
+
#if (defined _POSIX_SOURCE \
|| (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1) \
|| defined _XOPEN_SOURCE)
@@ -351,10 +368,6 @@
# define __USE_GNU 1
#endif
-#if defined _REENTRANT || defined _THREAD_SAFE
-# define __USE_REENTRANT 1
-#endif
-
#if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0
# if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0
# warning _FORTIFY_SOURCE requires compiling with optimization (-O)
diff --git a/include/libc-symbols.h b/include/libc-symbols.h
index 1c91f2e..4238d79 100644
--- a/include/libc-symbols.h
+++ b/include/libc-symbols.h
@@ -52,8 +52,6 @@
/* Enable declarations of GNU extensions, since we are compiling them. */
#define _GNU_SOURCE 1
-/* And we also need the data for the reentrant functions. */
-#define _REENTRANT 1
#include <config.h>
diff --git a/manual/creature.texi b/manual/creature.texi
index 257f871..5048886 100644
--- a/manual/creature.texi
+++ b/manual/creature.texi
@@ -219,15 +219,11 @@ cause them to be disabled.
@comment GNU
@defvr Macro _REENTRANT
@defvrx Macro _THREAD_SAFE
-If you define one of these macros, reentrant versions of several functions get
-declared. Some of the functions are specified in POSIX.1c but many others
-are only available on a few other systems or are unique to @theglibc{}.
-The problem is the delay in the standardization of the thread safe C library
-interface.
-
-Unlike on some other systems, no special version of the C library must be
-used for linking. There is only one version but while compiling this
-it must have been specified to compile as thread safe.
+These macros are obsolete. They have the same effect as defining
+@code{_POSIX_C_SOURCE} with the value @code{199506L}.
+
+Some very old C libraries required one of these macros to be defined
+for basic functionality (e.g.@: @code{getchar}) to be thread-safe.
@end defvr
We recommend you use @code{_GNU_SOURCE} in new programs. If you don't
diff --git a/posix/bits/unistd.h b/posix/bits/unistd.h
index 0105f04..4a5f42e 100644
--- a/posix/bits/unistd.h
+++ b/posix/bits/unistd.h
@@ -302,7 +302,7 @@ __NTH (ttyname_r (int __fd, char *__buf, size_t __buflen))
}
-#if defined __USE_REENTRANT || defined __USE_POSIX199506
+#ifdef __USE_POSIX199506
extern int __getlogin_r_chk (char *__buf, size_t __buflen, size_t __nreal)
__nonnull ((1));
extern int __REDIRECT (__getlogin_r_alias, (char *__buf, size_t __buflen),
diff --git a/posix/unistd.h b/posix/unistd.h
index 625ba77..392dc0e 100644
--- a/posix/unistd.h
+++ b/posix/unistd.h
@@ -849,7 +849,7 @@ extern int tcsetpgrp (int __fd, __pid_t __pgrp_id) __THROW;
This function is a possible cancellation point and therefore not
marked with __THROW. */
extern char *getlogin (void);
-#if defined __USE_REENTRANT || defined __USE_POSIX199506
+#ifdef __USE_POSIX199506
/* Return at most NAME_LEN characters of the login name of the user in NAME.
If it cannot be determined or some other error occurred, return the error
code. Otherwise return 0.
diff --git a/scripts/check-installed-headers.sh b/scripts/check-installed-headers.sh
index a245fe6..89e1514 100644
--- a/scripts/check-installed-headers.sh
+++ b/scripts/check-installed-headers.sh
@@ -143,7 +143,6 @@ EOF
inappropriate for this test. */
#undef _LIBC
#undef _GNU_SOURCE
-#undef _REENTRANT
/* The library mode is selected here rather than on the command line to
ensure that this selection wins. */
$expanded_lib_mode
-----------------------------------------------------------------------
Summary of changes:
NEWS | 13 +++++++++++
include/features.h | 41 +++++++++++++++++++++++------------
include/libc-symbols.h | 2 -
manual/creature.texi | 14 ++++--------
posix/bits/unistd.h | 2 +-
posix/unistd.h | 2 +-
scripts/check-installed-headers.sh | 1 -
7 files changed, 47 insertions(+), 28 deletions(-)
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