C2x adds binary integer constants starting with 0b or 0B, and supports
those constants for the %i scanf format (in addition to the %b format,
which isn't yet implemented for scanf in glibc). Implement that scanf
support for glibc.
As with the strtol support, this is incompatible with previous C
standard versions, in that such an input string starting with 0b or 0B
was previously required to be parsed as 0 (with the rest of the input
potentially matching subsequent parts of the scanf format string).
Thus this patch adds 12 new __isoc23_* functions per long double
format (12, 24 or 36 depending on how many long double formats the
glibc configuration supports), with appropriate header redirection
support (generally very closely following that for the __isoc99_*
scanf functions - note that __GLIBC_USE (DEPRECATED_SCANF) takes
precedence over __GLIBC_USE (C2X_STRTOL), so the case of GNU
extensions to C89 continues to get old-style GNU %a and does not get
this new feature). The function names would remain as __isoc23_* even
if C2x ends up published in 2024 rather than 2023.
When scanf %b support is added, I think it will be appropriate for all
versions of scanf to follow C2x rules for inputs to the %b format
(given that there are no compatibility concerns for a new format).
Tested for x86_64 (full glibc testsuite). The first version was also
tested for powerpc (32-bit) and powerpc64le (stdio-common/ and wcsmbs/
tests), and with build-many-glibcs.py.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.
I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah. I don't
know why I run into these diagnostics whereas others evidently do not.
remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
Patterns like %*[ can safely be used to match a great many characters,
and it's quite realisitic to use them for more than INT_MAX characters
from an IO stream.
With the previous approach, after INT_MAX characters (v)fscanf would
return successfully, indicating an end to the match, even though there
wasn't one.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
As noted in <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97264>, the cast
in the call to the read_int function is an aliasing violation. Change the
type of local variable f to a pointer to unsigned, which allows to
eliminate most casts while only adding three new ones.
This patch fixes further coding style issues where code should have
broken lines before operators in accordance with the GNU Coding
Standards but instead was breaking lines after them.
Tested for x86_64, and with build-many-glibcs.py.
* stdio-common/vfscanf-internal.c (ARG): Break lines before rather
than after operators.
* sysdeps/mach/hurd/setitimer.c (timer_thread): Likewise.
(setitimer_locked): Likewise.
* sysdeps/mach/hurd/sigaction.c (__sigaction): Likewise.
* sysdeps/mach/hurd/sigaltstack.c (__sigaltstack): Likewise.
* sysdeps/mach/pagecopy.h (PAGE_COPY_FWD): Likewise.
* sysdeps/mach/thread_state.h (machine_get_basic_state): Likewise.
* sysdeps/powerpc/powerpc64/tst-ucontext-ppc64-vscr.c
(PPC_CPU_SUPPORTED): Likewise.
* sysdeps/unix/sysv/linux/alpha/a.out.h (N_TXTOFF): Likewise.
* sysdeps/unix/sysv/linux/generic/wordsize-32/overflow.h
(stat_overflow): Likewise.
(statfs_overflow): Likewise.
* sysdeps/unix/sysv/linux/tst-personality.c (do_test): Likewise.
* sysdeps/unix/sysv/linux/tst-ttyname.c (eq_ttyname): Likewise.
(eq_ttyname_r): Likewise.
(run_chroot_tests): Likewise.
On powerpc64le, long double can currently take two formats: the same as
double (-mlong-double-64) or IBM Extended Precision (default with
-mlong-double-128 or explicitly with -mabi=ibmlongdouble). The internal
implementation of scanf-like functions is aware of these possibilites
and, based on the format in use, properly calls __strtold_internal or
__strtod_internal, saving the return to a variable of type double or
long double.
When library support for TS 18661-3 was added to glibc, a new function,
__strtof128_internal, was added to enable reading of floating-point
values with IEEE binary128 format into the _Float128 type. Now that
powerpc64le is getting support for its third long double format, and
taking into account that this format is the same as the format of
_Float128, this patch extends __vfscanf_internal and __vfwscanf_internal
to call __strtof128_internal or __wcstof128_internal when appropriate.
The result gets saved into a variable of _Float128 type.
Tested for powerpc64le.
Change the callers of __vfscanf_internal and __vfwscanf_internal that
want to treat 'long double' as another name for 'double' (all of which
happen to be in sysdeps/ieee754/ldbl-opt/nldbl-compat.c) to communicate
this via the new flags argument, instead of the per-thread variable
__no_long_double and its __ldbl_is_dbl wrapper macro.
Tested for powerpc and powerpc64le.
Change the callers of __vfscanf_internal and __vfwscanf_internal that
want C99-compliant behavior to communicate this via the new flags
argument, rather than setting bits on the FILE object. This also
means these functions do not need to do their own locking.
Tested for powerpc and powerpc64le.
There are two flags currently defined: SCANF_LDBL_IS_DBL is the mode
used by __nldbl_ scanf variants, and SCANF_ISOC99_A is the mode used
by __isoc99_ scanf variants. In this patch, the new functions honor
these flag bits if they're set, but they still also look at the
corresponding bits of environmental state, and callers all pass zero.
The new functions do *not* have the "errp" argument possessed by
_IO_vfscanf and _IO_vfwscanf. All internal callers passed NULL for
that argument. External callers could theoretically exist, so I
preserved wrappers, but they are flagged as compat symbols and they
don't preserve the three-way distinction among types of errors that
was formerly exposed. These functions probably should have been in
the list of deprecated _IO_ symbols in 2.27 NEWS -- they're not just
aliases for vfscanf and vfwscanf.
(It was necessary to introduce ldbl_compat_symbol for _IO_vfscanf.
Please check that part of the patch very carefully, I am still not
confident I understand all of the details of ldbl-opt.)
This patch also introduces helper inlines in libio/strfile.h that
encapsulate the process of initializing an _IO_strfile object for
reading. This allows us to call __vfscanf_internal directly from
sscanf, and __vfwscanf_internal directly from swscanf, without
duplicating the initialization code. (Previously, they called their
v-counterparts, but that won't work if we want to control *both* C99
mode and ldbl-is-dbl mode using the flags argument to__vfscanf_internal.)
It's still a little awkward, especially for wide strfiles, but it's
much better than what we had.
Tested for powerpc and powerpc64le.
