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Zack Weinberg c03073774f 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.
2016-12-08 15:45:33 -05:00
argp Installed-header hygiene (BZ#20366): Simple self-contained fixes. 2016-09-23 08:43:55 -04:00
assert
benchtests Use -fno-builtin for sqrt benchmark. 2016-10-21 21:18:03 +00:00
bits Refactor FP_ILOGB* out of bits/mathdef.h. 2016-12-01 02:56:55 +00:00
catgets
conform Enable linknamespace testing for libdl and libcrypt. 2016-11-16 22:47:57 +00:00
crypt Fix crypt snprintf namespace (bug 20829). 2016-11-16 22:46:48 +00:00
csu Remove __libc_csu_irel declaration 2016-09-10 15:50:53 +05:30
ctype
debug Add tests for fortification of bcopy and bzero. 2016-08-19 09:04:35 -04:00
dirent
dlfcn Implement _dl_catch_error, _dl_signal_error in libc.so [BZ #16628] 2016-11-30 15:59:57 +01:00
elf Bug 20918 - Building with --enable-nss-crypt fails tst-linkall-static 2016-12-02 15:39:09 -05:00
gmon Installed-header hygiene (BZ#20366): obsolete BSD u_* types. 2016-09-23 08:43:56 -04:00
gnulib
grp Don't install the internal header grp-merge.h 2016-07-18 09:33:21 -03:00
gshadow
hesiod
hurd hurd: fix using hurd.h in C++ programs 2016-12-04 23:18:32 +01:00
iconv gconv.h: fix build with GCC 7 2016-11-06 21:33:10 +01:00
iconvdata gconv: Adjust GBK to support the Euro sign 2016-11-29 18:35:21 +01:00
include Make _REENTRANT and _THREAD_SAFE aliases for _POSIX_C_SOURCE=199506L. 2016-12-08 15:45:33 -05:00
inet Installed-header hygiene (BZ#20366): conditionally defined structures. 2016-09-23 08:43:56 -04:00
intl hurd: fix pathconf visibility 2016-09-18 23:45:12 +02:00
io New internal function __access_noerrno 2016-11-16 15:53:58 -02:00
libidn
libio libio: Limit buffer size to 8192 bytes [BZ #4099] 2016-11-30 14:59:27 +01:00
locale Bug 20729: Include libc-internal.h where required. 2016-10-31 16:46:57 -04:00
localedata localedata: GBK: add mapping for 0x80->Euro sign [BZ #20864] 2016-11-26 17:20:22 -05:00
login
mach Fix old-style function definition 2016-09-20 23:10:51 +02:00
malloc malloc: Update comments about chunk layout 2016-10-28 22:36:58 +02:00
manual Make _REENTRANT and _THREAD_SAFE aliases for _POSIX_C_SOURCE=199506L. 2016-12-08 15:45:33 -05:00
math Install libm.a as linker script (bug 20539). 2016-12-08 17:25:59 +03:00
mathvec
misc Fix multiple definitions of mk[o]stemp[s]64 2016-11-22 13:51:19 +01:00
nis Installed-header hygiene (BZ#20366): Simple self-contained fixes. 2016-09-23 08:43:55 -04:00
nptl Add pretty printers for the NPTL lock types 2016-12-08 18:59:02 +05:30
nptl_db Remove cached PID/TID in clone 2016-11-24 19:38:51 -02:00
nscd Fix incorrect double-checked locking related to _res_hconf.initialized. 2016-08-18 20:53:37 +02:00
nss Fix incorrect double-checked locking related to _res_hconf.initialized. 2016-08-18 20:53:37 +02:00
po Update PO files. 2016-08-04 11:41:27 -04:00
posix Make _REENTRANT and _THREAD_SAFE aliases for _POSIX_C_SOURCE=199506L. 2016-12-08 15:45:33 -05:00
pwd
resolv Bug 20729: Fix build failures on ppc64 and other arches. 2016-11-02 13:01:36 -04:00
resource
rt Use libc_ifunc macro for clock_* symbols in librt. 2016-10-07 10:12:47 +02:00
scripts Make _REENTRANT and _THREAD_SAFE aliases for _POSIX_C_SOURCE=199506L. 2016-12-08 15:45:33 -05:00
setjmp
shadow
signal Installed-header hygiene (BZ#20366): time.h types. 2016-09-23 08:43:56 -04:00
socket Installed-header hygiene (BZ#20366): conditionally defined structures. 2016-09-23 08:43:56 -04:00
soft-fp [soft-fp] Add support for various half-precision conversion routines. 2016-09-21 21:02:54 +00:00
stdio-common Fix crypt snprintf namespace (bug 20829). 2016-11-16 22:46:48 +00:00
stdlib Ignore -Wmaybe-uninitialized in stdlib/bug-getcontext.c. 2016-11-11 21:05:51 +00:00
streams
string Correct comments in string.h re strcoll_l, strxfrm_l. 2016-11-16 14:18:32 -05:00
sunrpc Fix build-and-build-again bug in sunrpc tests. 2016-11-14 14:25:11 -05:00
sysdeps Get rid of __elision_available 2016-12-07 09:35:07 +01:00
sysvipc Installed-header hygiene (BZ#20366): time.h types. 2016-09-23 08:43:56 -04:00
termios
time Fix -Wformat-length warning in time/tst-strptime2.c 2016-11-02 16:00:39 -07:00
timezone
wcsmbs Add tst-wcstod-round 2016-08-19 11:17:07 -05:00
wctype
.gitattributes
.gitignore
BUGS
CONFORMANCE
COPYING
COPYING.LIB
ChangeLog Fix tests-printers handling for cross compiling. 2016-12-08 18:54:13 +00:00
ChangeLog.1
ChangeLog.2
ChangeLog.3
ChangeLog.4
ChangeLog.5
ChangeLog.6
ChangeLog.7
ChangeLog.8 ChangeLog: change Winblowz to Windows 2016-08-10 00:49:28 +08:00
ChangeLog.9
ChangeLog.10
ChangeLog.11 ChangeLog: change Winblowz to Windows 2016-08-10 00:49:28 +08:00
ChangeLog.12
ChangeLog.13
ChangeLog.14
ChangeLog.15
ChangeLog.16
ChangeLog.17
ChangeLog.old-ports
ChangeLog.old-ports-aarch64
ChangeLog.old-ports-aix
ChangeLog.old-ports-alpha
ChangeLog.old-ports-am33
ChangeLog.old-ports-arm
ChangeLog.old-ports-cris
ChangeLog.old-ports-hppa
ChangeLog.old-ports-ia64
ChangeLog.old-ports-linux-generic
ChangeLog.old-ports-m68k
ChangeLog.old-ports-microblaze
ChangeLog.old-ports-mips
ChangeLog.old-ports-powerpc
ChangeLog.old-ports-tile
INSTALL Add pretty printers for the NPTL lock types 2016-12-08 18:59:02 +05:30
LICENSES
Makeconfig Add pretty printers for the NPTL lock types 2016-12-08 18:59:02 +05:30
Makefile Installed header hygiene (BZ#20366): Test of installed headers. 2016-09-23 08:43:56 -04:00
Makefile.in
Makerules Install libm.a as linker script (bug 20539). 2016-12-08 17:25:59 +03:00
NAMESPACE
NEWS Make _REENTRANT and _THREAD_SAFE aliases for _POSIX_C_SOURCE=199506L. 2016-12-08 15:45:33 -05:00
README
README.pretty-printers Add pretty printers for the NPTL lock types 2016-12-08 18:59:02 +05:30
Rules Fix tests-printers handling for cross compiling. 2016-12-08 18:54:13 +00:00
WUR-REPORT
abi-tags
aclocal.m4
config.h.in Add configure check to test if gcc supports attribute ifunc. 2016-10-07 10:02:59 +02:00
config.make.in Bug 20918 - Building with --enable-nss-crypt fails tst-linkall-static 2016-12-02 15:39:09 -05:00
configure Bug 20918 - Building with --enable-nss-crypt fails tst-linkall-static 2016-12-02 15:39:09 -05:00
configure.ac Bug 20918 - Building with --enable-nss-crypt fails tst-linkall-static 2016-12-02 15:39:09 -05:00
cppflags-iterator.mk
extra-lib.mk
extra-modules.mk
gen-locales.mk
libc-abis
o-iterator.mk
shlib-versions
test-skeleton.c Minor problems exposed by compiling C++ tests under _ISOMAC. 2016-11-27 12:36:16 -05:00
version.h Open development for 2.25. 2016-08-01 23:00:21 -04:00

README

This directory contains the sources of the GNU C Library.
See the file "version.h" for what release version you have.

The GNU C Library is the standard system C library for all GNU systems,
and is an important part of what makes up a GNU system.  It provides the
system API for all programs written in C and C-compatible languages such
as C++ and Objective C; the runtime facilities of other programming
languages use the C library to access the underlying operating system.

In GNU/Linux systems, the C library works with the Linux kernel to
implement the operating system behavior seen by user applications.
In GNU/Hurd systems, it works with a microkernel and Hurd servers.

The GNU C Library implements much of the POSIX.1 functionality in the
GNU/Hurd system, using configurations i[4567]86-*-gnu.  The current
GNU/Hurd support requires out-of-tree patches that will eventually be
incorporated into an official GNU C Library release.

When working with Linux kernels, this version of the GNU C Library
requires Linux kernel version 3.2 or later on all architectures except
i[4567]86 and x86_64, where Linux kernel version 2.6.32 or later
suffices.

Also note that the shared version of the libgcc_s library must be
installed for the pthread library to work correctly.

The GNU C Library supports these configurations for using Linux kernels:

	aarch64*-*-linux-gnu
	alpha*-*-linux-gnu
	arm-*-linux-gnueabi
	hppa-*-linux-gnu	Not currently functional without patches.
	i[4567]86-*-linux-gnu
	x86_64-*-linux-gnu	Can build either x86_64 or x32
	ia64-*-linux-gnu
	m68k-*-linux-gnu
	microblaze*-*-linux-gnu
	mips-*-linux-gnu
	mips64-*-linux-gnu
	powerpc-*-linux-gnu	Hardware or software floating point, BE only.
	powerpc64*-*-linux-gnu	Big-endian and little-endian.
	s390-*-linux-gnu
	s390x-*-linux-gnu
	sh[34]-*-linux-gnu
	sparc*-*-linux-gnu
	sparc64*-*-linux-gnu
	tilegx-*-linux-gnu
	tilepro-*-linux-gnu

If you are interested in doing a port, please contact the glibc
maintainers; see http://www.gnu.org/software/libc/ for more
information.

See the file INSTALL to find out how to configure, build, and install
the GNU C Library.  You might also consider reading the WWW pages for
the C library at http://www.gnu.org/software/libc/.

The GNU C Library is (almost) completely documented by the Texinfo manual
found in the `manual/' subdirectory.  The manual is still being updated
and contains some known errors and omissions; we regret that we do not
have the resources to work on the manual as much as we would like.  For
corrections to the manual, please file a bug in the `manual' component,
following the bug-reporting instructions below.  Please be sure to check
the manual in the current development sources to see if your problem has
already been corrected.

Please see http://www.gnu.org/software/libc/bugs.html for bug reporting
information.  We are now using the Bugzilla system to track all bug reports.
This web page gives detailed information on how to report bugs properly.

The GNU C Library is free software.  See the file COPYING.LIB for copying
conditions, and LICENSES for notices about a few contributions that require
these additional notices to be distributed.  License copyright years may be
listed using range notation, e.g., 1996-2015, indicating that every year in
the range, inclusive, is a copyrightable year that would otherwise be listed
individually.