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This patch starts preparation for C2Y support in glibc headers by
adding a feature test macro _ISOC2Y_SOURCE and corresponding
__GLIBC_USE (ISOC2Y). (I mostly copied the work of Joseph Myers
for C2X). As with other such macros, C2Y features are also
enabled by compiling for a standard newer than C23, or by using
_GNU_SOURCE.
This patch does not itself enable anything new in the headers for C2Y;
that is to be done in followup patches. (For example an implementation
of WG14 N3349.)
Once C2Y becomes an actual standard we'll presumably move to using the
actual year in the feature test macro and __GLIBC_USE, with some
period when both macro spellings are accepted, as was done with
_ISOC2X_SOURCE.
Tested for x86_64.
Signed-off-by: Lenard Mollenkopf <glibc@lenardmollenkopf.de>
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It was raised on libc-help [1] that some Linux kernel interfaces expect
the libc to define __USE_TIME_BITS64 to indicate the time_t size for the
kABI. Different than defined by the initial y2038 design document [2],
the __USE_TIME_BITS64 is only defined for ABIs that support more than
one time_t size (by defining the _TIME_BITS for each module).
The 64 bit time_t redirects are now enabled using a different internal
define (__USE_TIME64_REDIRECTS). There is no expected change in semantic
or code generation.
Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and
arm-linux-gnueabi
[1] https://sourceware.org/pipermail/libc-help/2024-January/006557.html
[2] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign
Reviewed-by: DJ Delorie <dj@redhat.com>
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WG14 decided to use the name C23 as the informal name of the next
revision of the C standard (notwithstanding the publication date in
2024). Update references to C2X in glibc to use the C23 name.
This is intended to update everything *except* where it involves
renaming files (the changes involving renaming tests are intended to
be done separately). In the case of the _ISOC2X_SOURCE feature test
macro - the only user-visible interface involved - support for that
macro is kept for backwards compatibility, while adding
_ISOC23_SOURCE.
Tested for x86_64.
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* manual/creature.texi (Feature Test Macros): Fix
“creature.texi:309: warning: `.' or `,' must follow @xref, not f”.
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There have been multiple requests to provide more detail on how the
_FORTIFY_SOURCE macro works, so this patch adds a new node in the
Library Maintenance section that does this. A lot of the description is
implementation detail, which is why I put this in the appendix and not
in the main documentation.
Resolves: BZ #28998.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
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The @refill command has been obsolete for a while and now texinfo has
started warning about it.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
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The current language reads "This macro determines...", changing to
"Define this macro...". This is consistent with other feature macro
documentation language.
When I first read the previous language it seems to indicate that the
macro is already defined. By changing the language to "Define this
macro..." it's clear that its the user's responsibility to define it.
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The constant PTHREAD_STACK_MIN may be too small for some processors.
Rename _SC_SIGSTKSZ_SOURCE to _DYNAMIC_STACK_SIZE_SOURCE. When
_DYNAMIC_STACK_SIZE_SOURCE or _GNU_SOURCE are defined, define
PTHREAD_STACK_MIN to sysconf(_SC_THREAD_STACK_MIN) which is changed
to MIN (PTHREAD_STACK_MIN, sysconf(_SC_MINSIGSTKSZ)).
Consolidate <bits/local_lim.h> with <bits/pthread_stack_min.h> to
provide a constant target specific PTHREAD_STACK_MIN value.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
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* NEWS: Don't imply the default will always be 32-bit.
* manual/creature.texi (Feature Test Macros):
Say that _TIME_BITS and _FILE_OFFSET_BITS defaults
may change in future releases.
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A new build flag, _TIME_BITS, enables the usage of the newer 64-bit
time symbols for legacy ABI (where 32-bit time_t is default). The 64
bit time support is only enabled if LFS (_FILE_OFFSET_BITS=64) is
also used.
Different than LFS support, the y2038 symbols are added only for the
required ABIs (armhf, csky, hppa, i386, m68k, microblaze, mips32,
mips64-n32, nios2, powerpc32, sparc32, s390-32, and sh). The ABIs with
64-bit time support are unchanged, both for symbol and types
redirection.
On Linux the full 64-bit time support requires a minimum of kernel
version v5.1. Otherwise, the 32-bit fallbacks are used and might
results in error with overflow return code (EOVERFLOW).
The i686-gnu does not yet support 64-bit time.
This patch exports following rediretions to support 64-bit time:
* libc:
adjtime
adjtimex
clock_adjtime
clock_getres
clock_gettime
clock_nanosleep
clock_settime
cnd_timedwait
ctime
ctime_r
difftime
fstat
fstatat
futimens
futimes
futimesat
getitimer
getrusage
gettimeofday
gmtime
gmtime_r
localtime
localtime_r
lstat_time
lutimes
mktime
msgctl
mtx_timedlock
nanosleep
nanosleep
ntp_gettime
ntp_gettimex
ppoll
pselec
pselect
pthread_clockjoin_np
pthread_cond_clockwait
pthread_cond_timedwait
pthread_mutex_clocklock
pthread_mutex_timedlock
pthread_rwlock_clockrdlock
pthread_rwlock_clockwrlock
pthread_rwlock_timedrdlock
pthread_rwlock_timedwrlock
pthread_timedjoin_np
recvmmsg
sched_rr_get_interval
select
sem_clockwait
semctl
semtimedop
sem_timedwait
setitimer
settimeofday
shmctl
sigtimedwait
stat
thrd_sleep
time
timegm
timerfd_gettime
timerfd_settime
timespec_get
utime
utimensat
utimes
utimes
wait3
wait4
* librt:
aio_suspend
mq_timedreceive
mq_timedsend
timer_gettime
timer_settime
* libanl:
gai_suspend
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
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ISO C2X has made some changes to the handling of feature test macros
related to features from the floating-point TSes, and to exactly what
such features are present in what headers, that require corresponding
changes in glibc.
* For the few features that were controlled by
__STDC_WANT_IEC_60559_BFP_EXT__ (and the corresponding DFP macro) in
C2X, there is now instead a new feature test macro
__STDC_WANT_IEC_60559_EXT__ covering both binary and decimal FP.
This controls CR_DECIMAL_DIG in <float.h> (provided by GCC; I
implemented support for the new feature test macro for GCC 11) and
the totalorder and payload functions in <math.h>. C2X no longer
says anything about __STDC_WANT_IEC_60559_BFP_EXT__ (so it's
appropriate for that macro to continue to enable exactly the
features from TS 18661-1).
* The SNAN macros for each floating-point type have moved to <float.h>
(and been renamed in the process). Thus, the copies in <math.h>
should only be defined for __STDC_WANT_IEC_60559_BFP_EXT__, not for
C2X.
* The fmaxmag and fminmag functions have been removed (replaced by new
functions for the new min/max operations in IEEE 754-2019). Thus
those should also only be declared for
__STDC_WANT_IEC_60559_BFP_EXT__.
* The _FloatN / _FloatNx handling for the last two points in glibc is
trickier, since __STDC_WANT_IEC_60559_TYPES_EXT__ is still in C2X
(the integration of TS 18661-3 as an Annex, that is, which hasn't
yet been merged into the C standard git repository but has been
accepted by WG14), so C2X with that macro should not declare some
things that are declared for older standards with that macro. The
approach taken here is to provide the declarations (when
__STDC_WANT_IEC_60559_TYPES_EXT__ is enabled) only when (defined
__USE_GNU || !__GLIBC_USE (ISOC2X)), so if C2X features are enabled
then those declarations (that are only in TS 18661-3 and not in C2X)
will only be provided if _GNU_SOURCE is defined as well. Thus
_GNU_SOURCE remains a superset of the TS features as well as of C2X.
Some other somewhat related changes in C2X are not addressed here.
There's an open proposal not to include the fmin and fmax functions
for the _FloatN / _FloatNx types, given the new min/max operations,
which could be handled like the previous point if adopted. And the
fromfp functions have been changed to return a result in floating type
rather than intmax_t / uintmax_t; my inclination there is to treat
that like that change of totalorder type (new symbol versions etc. for
the ABI change; old versions become compat symbols and are no longer
supported as an API).
Tested for x86_64 and x86.
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Add _SC_MINSIGSTKSZ for the minimum signal stack size derived from
AT_MINSIGSTKSZ, which is the minimum number of bytes of free stack
space required in order to gurantee successful, non-nested handling
of a single signal whose handler is an empty function, and _SC_SIGSTKSZ
which is the suggested minimum number of bytes of stack space required
for a signal stack.
If AT_MINSIGSTKSZ isn't available, sysconf (_SC_MINSIGSTKSZ) returns
MINSIGSTKSZ. On Linux/x86 with XSAVE, the signal frame used by kernel
is composed of the following areas and laid out as:
------------------------------
| alignment padding |
------------------------------
| xsave buffer |
------------------------------
| fsave header (32-bit only) |
------------------------------
| siginfo + ucontext |
------------------------------
Compute AT_MINSIGSTKSZ value as size of xsave buffer + size of fsave
header (32-bit only) + size of siginfo and ucontext + alignment padding.
If _SC_SIGSTKSZ_SOURCE or _GNU_SOURCE are defined, MINSIGSTKSZ and SIGSTKSZ
are redefined as
/* Default stack size for a signal handler: sysconf (SC_SIGSTKSZ). */
# undef SIGSTKSZ
# define SIGSTKSZ sysconf (_SC_SIGSTKSZ)
/* Minimum stack size for a signal handler: SIGSTKSZ. */
# undef MINSIGSTKSZ
# define MINSIGSTKSZ SIGSTKSZ
Compilation will fail if the source assumes constant MINSIGSTKSZ or
SIGSTKSZ.
The reason for not simply increasing the kernel's MINSIGSTKSZ #define
(apart from the fact that it is rarely used, due to glibc's shadowing
definitions) was that userspace binaries will have baked in the old
value of the constant and may be making assumptions about it.
For example, the type (char [MINSIGSTKSZ]) changes if this #define
changes. This could be a problem if an newly built library tries to
memcpy() or dump such an object defined by and old binary.
Bounds-checking and the stack sizes passed to things like sigaltstack()
and makecontext() could similarly go wrong.
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Introduce a new _FORTIFY_SOURCE level of 3 to enable additional
fortifications that may have a noticeable performance impact, allowing
more fortification coverage at the cost of some performance.
With llvm 9.0 or later, this will replace the use of
__builtin_object_size with __builtin_dynamic_object_size.
__builtin_dynamic_object_size
-----------------------------
__builtin_dynamic_object_size is an LLVM builtin that is similar to
__builtin_object_size. In addition to what __builtin_object_size
does, i.e. replace the builtin call with a constant object size,
__builtin_dynamic_object_size will replace the call site with an
expression that evaluates to the object size, thus expanding its
applicability. In practice, __builtin_dynamic_object_size evaluates
these expressions through malloc/calloc calls that it can associate
with the object being evaluated.
A simple motivating example is below; -D_FORTIFY_SOURCE=2 would miss
this and emit memcpy, but -D_FORTIFY_SOURCE=3 with the help of
__builtin_dynamic_object_size is able to emit __memcpy_chk with the
allocation size expression passed into the function:
void *copy_obj (const void *src, size_t alloc, size_t copysize)
{
void *obj = malloc (alloc);
memcpy (obj, src, copysize);
return obj;
}
Limitations
-----------
If the object was allocated elsewhere that the compiler cannot see, or
if it was allocated in the function with a function that the compiler
does not recognize as an allocator then __builtin_dynamic_object_size
also returns -1.
Further, the expression used to compute object size may be non-trivial
and may potentially incur a noticeable performance impact. These
fortifications are hence enabled at a new _FORTIFY_SOURCE level to
allow developers to make a choice on the tradeoff according to their
environment.
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This patch starts preparation for C2X support in glibc headers by
adding a feature test macro _ISOC2X_SOURCE and corresponding
__GLIBC_USE (ISOC2X). (I chose to use the newer __GLIBC_USE style for
this rather than the older __USE_* macros tested with #ifdef.) As
with other such macros, C2X features are also enabled by compiling for
a standard newer than C17, or by using _GNU_SOURCE.
This patch does not itself enable anything new in the headers for C2X;
that is to be done in followup patches. (For example, most of the TS
18661-1 functions should be declared for C2X without any
__STDC_WANT_IEC_60559_BFP_EXT__ being needed, but the ones that
18661-1 adds to Annex F because of their close relation to IEEE 754
formats do still need the WANT macro in C2X.)
Once C2X becomes an actual standard we'll presumably move to using the
actual year in the feature test macro and __GLIBC_USE, with some
period when both macro spellings are accepted, as was done with
_ISOC9X_SOURCE.
Tested for x86_64.
* include/features.h (_ISOC2X_SOURCE): New feature test macro.
Undefine and define to 1 if [_GNU_SOURCE].
(__GLIBC_USE_ISOC2X): New macro. Undefine and redefine depending
on [_ISOC2X_SOURCE] and [__STDC_VERSION__ > 201710L].
(__USE_ISOC11): Also define to 1 if [_ISOC2X_SOURCE].
(__USE_ISOC99): Likewise.
(__USE_ISOC95): Likewise.
* manual/creature.texi (_ISOC2X_SOURCE): Document.
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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.
[BZ #22862]
* include/features.h: Add _ISOC11_SOURCE to test for whether
to define _DEFAULT_SOURCE.
* manual/creature.texi (_DEFAULT_SOURCE): Improve
documentation.
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The current description refers to ISO C99 not being widely adopted,
which it is believed to be now.
* manual/creature.texi (_ISOC99_SOURCE): Update the dated
description.
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Several feature test macros are documented in features.h but absent in
the manual, and some documented macros accept undocumented values.
This commit updates the manual to mention all the accepted macros,
along with any values that hold special meaning.
* manual/creature.texi (_POSIX_C_SOURCE): Document special
values of 199606L, 200112L, and 200809L.
(_XOPEN_SOURCE): Document special values of 600 and 700.
(_ISOC11_SOURCE): Document macro.
(_ATFILE_SOURCE): Likewise.
(_FORTIFY_SOURCE): Likewise.
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A number of cross-references to the GCC info manual cause Texinfo
warnings; e.g.:
./creature.texi:11: warning: @xref node name should not contain `.'
This is due to "gcc.info" being used in the INFO-FILE-NAME (fourth)
argument. Changing it to "gcc" removes these warnings. (Manually
confirmed equivalent behaviour for make info, html, and pdf.)
* manual/creature.texi: Convert references to gcc.info to gcc.
* manual/stdio.texi: Likewise.
* manual/string.texi: Likewise.
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* manual/creature.texi (_REENTRANT): Annotate as obsolete.
(_THREAD_SAFE): Likewise.
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The Summary is now generated from @standards, and syntax-checking is
performed. If invalid @standards syntax is detected, summary.pl will
fail, reporting all errors. Failure and error reporting is disabled
for now, however, since much of the manual is still incomplete
wrt. header and standards annotations.
Note that the sorting order of the Summary has changed; summary.pl
respects the locale, like summary.awk did, but the use of LC_ALL=C is
introduced in the Makefile. Other notable deviations are improved
detection of the annotated elements' names, which are used for
sorting, and improved detection of the @node used to reference into
the manual. The most noticeable difference in the rendered Summary is
that entries may now contain multiple lines, one for each header and
standard combination.
summary.pl accepts a `--help' option, which details the expected
syntax of @standards. If errors are reported, the user is directed to
this feature for further information.
* manual/Makefile: Generate summary.texi with summary.pl.
Force use of the C locale. Update Perl dependency comment.
* manual/header.texi: Update reference to summary.awk.
* manual/macros.texi: Refer authors to `summary.pl --help'.
* manual/summary.awk: Remove file.
* manual/summary.pl: New file. Generate summary.texi, and
check for @standards-related syntax errors.
* manual/argp.texi: Convert header and standards @comments to
@standards.
* manual/arith.texi: Likewise.
* manual/charset.texi: Likewise.
* manual/conf.texi: Likewise.
* manual/creature.texi: Likewise.
* manual/crypt.texi: Likewise.
* manual/ctype.texi: Likewise.
* manual/debug.texi: Likewise.
* manual/errno.texi: Likewise.
* manual/filesys.texi: Likewise.
* manual/getopt.texi: Likewise.
* manual/job.texi: Likewise.
* manual/lang.texi: Likewise.
* manual/llio.texi: Likewise.
* manual/locale.texi: Likewise.
* manual/math.texi: Likewise.
* manual/memory.texi: Likewise.
* manual/message.texi: Likewise.
* manual/pattern.texi: Likewise.
* manual/pipe.texi: Likewise.
* manual/process.texi: Likewise.
* manual/resource.texi: Likewise.
* manual/search.texi: Likewise.
* manual/setjmp.texi: Likewise.
* manual/signal.texi: Likewise.
* manual/socket.texi: Likewise.
* manual/startup.texi: Likewise.
* manual/stdio.texi: Likewise.
* manual/string.texi: Likewise.
* manual/sysinfo.texi: Likewise.
* manual/syslog.texi: Likewise.
* manual/terminal.texi: Likewise.
* manual/threads.texi: Likewise.
* manual/time.texi: Likewise.
* manual/users.texi: Likewise.
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This macro is defined by TS 18661-3 for supporting the _FloatN and
_FloatNx types, as well as the functions suffixed with fN.
* bits/libc-header-start.h:
(__GLIBC_USE_IEC_60559_TYPES_EXT): New macro.
* include/features.h: Describe __STDC_WANT_IEC_60559_TYPES_EXT__.
* manual/creature.texi: Likewise.
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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.
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This patch implements support for the
__STDC_WANT_IEC_60559_FUNCS_EXT__ feature test macro, following the
__GLIBC_USE approach used for other ISO C feature test macros.
Currently this only affects the exp10 functions (which glibc has had
for a long time).
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* bits/libc-header-start.h (__GLIBC_USE_IEC_60559_FUNCS_EXT): New
macro.
* include/features.h (__STDC_WANT_IEC_60559_FUNCS_EXT__):
Document.
* manual/creature.texi (__STDC_WANT_IEC_60559_FUNCS_EXT__):
Document macro.
* manual/math.texi (exp10): Document as ISO from TS 18661-4:2015.
(exp10f): Likewise.
(exp10l): Likewise.
* math/bits/mathcalls.h (exp10): Declare if
[__GLIBC_USE (IEC_60559_FUNCS_EXT)], not [__USE_GNU].
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This patch implements support for the __STDC_WANT_IEC_60559_BFP_EXT__
feature test macro from ISO/IEC 18661-1:2014, following the
__GLIBC_USE approach now used for __STDC_WANT_LIB_EXT2__. For this
macro, the relevant consideration is whether it is defined or
undefined when an affected header is included (not what its value is
if defined, and not whether it's defined or undefined when any other
unaffected system header is included).
Currently this macro only affects the issignaling macro and the nextup
and nextdown functions (so they can be enabled by defining this macro,
not just by defining _GNU_SOURCE as previously). Any further features
from this TS added in future would also be conditioned on this macro.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* bits/libc-header-start.h (__GLIBC_USE_IEC_60559_BFP_EXT): New
macro.
* include/features.h (__STDC_WANT_IEC_60559_BFP_EXT__): Document.
* manual/arith.texi (issignaling): Document as ISO from TS
18661-1:2014.
(nextup): Likewise.
(nextupf): Likewise.
(nextupl): Likewise.
(nextdown): Likewise.
(nextdownf): Likewise.
(nextdownl): Likewise.
* manual/creature.texi (__STDC_WANT_IEC_60559_BFP_EXT__): Document
macro.
* math/math.h: Define
__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include
<bits/libc-header-start.h> instead of including <features.h>.
(issignaling): Define if [__GLIBC_USE (IEC_60559_BFP_EXT)], not
[__USE_GNU].
* math/bits/mathcalls.h (nextdown): Declare if
[__GLIBC_USE (IEC_60559_BFP_EXT)], not [__USE_GNU].
(nextup): Likewise.
(__issignaling): Likewise.
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This patch implements support for the __STDC_WANT_LIB_EXT2__ feature
test macro from ISO/IEC TR 24731-2:2010, thereby implementing one
possible approach for supporting ISO C feature test macros.
Recall that, as described in
<https://sourceware.org/ml/libc-alpha/2016-05/msg00486.html>, these
macros work based on the definition when affected headers are
included, so cannot be handled once when the first system header is
included because that might not be one of the headers the particular
macro in question affects.
<https://sourceware.org/ml/libc-alpha/2016-05/msg00680.html> expresses
views on possible approaches for implementation and
<https://sourceware.org/ml/libc-alpha/2016-06/msg00039.html> follows
up on that.
This patch arranges things so that the relevant condition is
__GLIBC_USE (LIB_EXT2), following one of the suggestions given.
Headers using these macros include <bits/libc-header-start.h>, which
in turn includes <features.h>. Headers must define
__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION before including
<bits/libc-header-start.h>, to discourage inclusion outside glibc as
requested. __USE_GNU conditions on affected functions are changed to
__GLIBC_USE (LIB_EXT2), while it's added as an additional alternative
on the conditions for functions already enabled for some POSIX
versions.
It would be possible to convert existing __USE_* conditionals to
__GLIBC_USE (with the relevant __GLIBC_USE_* being defined in
<features.h> where __USE_* are presently defined), and so make them
typo-proof (given -Wundef -Werror in glibc builds) because __GLIBC_USE
is used with #if not #ifdef / #if defined.
No attempt is made to enforce the rule about diagnosing different
definitions of __STDC_WANT_LIB_EXT2__ when affected headers are
included; such a diagnostic is incompatible with multiple-include
guards on the affected headers, unless compiler extensions are added
to support it.
As previously noted, glibc does not implement all features from TR
24731-2:2010: the functions aswprintf vaswprintf getwdelim getwline
are not in glibc, although they would be appropriate to add if someone
wished to do so. But I think it makes sense to support the feature
test macro if *any* of the controlled features are present in glibc.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* bits/libc-header-start.h: New file.
* Makefile (headers): Add bits/libc-header-start.h.
* include/features.h (__STDC_WANT_LIB_EXT2__): Document.
(__GLIBC_USE): New macro.
* libio/stdio.h: Define
__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include
<bits/libc-header-start.h> instead of including <features.h>.
(fmemopen): Declare also if [__GLIBC_USE (LIB_EXT2)].
(open_memstream): Likewise.
(vasprintf): Declare if [__GLIBC_USE (LIB_EXT2)], not [__USE_GNU].
(__asprintf): Likewise.
(asprintf): Likewise.
(__getdelim): Declare also if [__GLIBC_USE (LIB_EXT2)].
(getdelim): Likewise.
(getline): Likewise.
* string/string.h: Define
__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include
<bits/libc-header-start.h> instead of including <features.h>.
(strdup): Declare also if [__GLIBC_USE (LIB_EXT2)]
(strndup): Likewise.
* wcsmbs/wchar.h: Define
__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include
<bits/libc-header-start.h> instead of including <features.h>.
(open_wmemstream): Declare also if [__GLIBC_USE (LIB_EXT2)].
* manual/creature.texi (__STDC_WANT_LIB_EXT2__): Document macro.
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This is a minimal patch to remove _BSD_SOURCE and _SVID_SOURCE from
the documented user API, making them into aliases for _DEFAULT_SOURCE
with a #warning given, but keeping most of the features.h logic using
those macros and all the exising __USE_* conditionals, on the basis
that all the consequent cleanups will go in followup patches.
Tested x86_64.
* include/features.h: Update comment documenting feature test
macros.
[_BSD_SOURCE || _SVID_SOURCE]: Give #warning. Define
_DEFAULT_SOURCE.
* manual/creature.texi (_BSD_SOURCE): Remove documentation.
(_SVID_SOURCE): Likewise.
(_DEFAULT_SOURCE): Update description of default features.
(Feature Test Macros): Don't mention _SVID_SOURCE in conjunction
with _GNU_SOURCE.
* manual/filesys.texi (__ftw_func_t): Do not refer to _BSD_SOURCE.
(S_ISVTX): Likewise.
* manual/math.texi (Mathematical Constants): Likewise.
* manual/signal.texi (Interrupted Primitives): Likewise.
* manual/startup.texi (putenv): Do not refer to _SVID_SOURCE.
* math/test-matherr.c (_SVID_SOURCE): Do not define.
* sysvipc/sys/ipc.h [__USE_SVID && !__USE_XOPEN && __GNUC__ >= 2]:
Don't refer to _SVID_SOURCE in warning text.
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This patch adds a feature test macro _DEFAULT_SOURCE to enable the
default set of header declarations.
The intention is: if _DEFAULT_SOURCE is not used there is no change to
the set of __USE_* macros glibc defines; if it's used on its own, and
without compiler options such as -std=c99 that define __STRICT_ANSI__,
again, there is no change; if it's used together with the macros it
approximately (i.e., apart from __USE_POSIX_IMPLICITLY) implies
(-D_BSD_SOURCE -D_SVID_SOURCE -D_POSIX_C_SOURCE=200809L), again, there
is no change. Otherwise, it causes the relevant features to be
enabled, even if __STRICT_ANSI__, or another feature test macro, would
cause them to be disabled.
This macro deliberately bundles the POSIX.1-2008 (non-X/Open)
functionality with the BSD/SVID/"misc" functionality, rather than
defining a macro that gives just the latter, as many of the header
cleanups resulting from removing _BSD_SOURCE and _SVID_SOURCE support
are only possible when BSD/SVID/"misc" is always bundled with
POSIX.1-2008.
Tested x86_64.
* include/features.h: Update comment documenting feature test
macros. Mention _DEFAULT_SOURCE in comment.
[_GNU_SOURCE] (_DEFAULT_SOURCE): Undefine and redefine.
[_DEFAULT_SOURCE]: Undefine and redefine _DEFAULT_SOURCE,
_BSD_SOURCE and _SVID_SOURCE.
[!__STRICT_ANSI__ && !_ISOC99_SOURCE && !_POSIX_SOURCE &&
!_POSIX_C_SOURCE && !_XOPEN_SOURCE && !_BSD_SOURCE &&
!_SVID_SOURCE]: Likewise.
[_DEFAULT_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE]
(__USE_POSIX_IMPLICITLY): Define.
[_DEFAULT_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE]
(_POSIX_SOURCE): Undefine and redefine.
[_DEFAULT_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE]
(_POSIX_C_SOURCE): Likewise.
* manual/creature.texi (_DEFAULT_SOURCE): Document.
(Feature Test Macros): Update documentation of default features.
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