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* [Bug libstdc++/110719] New: Should chrono formatters always use std::time_put for locale's representation?
@ 2023-07-18 14:43 redi at gcc dot gnu.org
2023-07-19 10:13 ` [Bug libstdc++/110719] " redi at gcc dot gnu.org
` (7 more replies)
0 siblings, 8 replies; 9+ messages in thread
From: redi at gcc dot gnu.org @ 2023-07-18 14:43 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110719
Bug ID: 110719
Summary: Should chrono formatters always use std::time_put for
locale's representation?
Product: gcc
Version: 13.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: redi at gcc dot gnu.org
Target Milestone: ---
auto t = std::chrono::system_clock::now();
auto loc = std::locale::classic();
std::cout << std::format(loc, "{:%EX %OS}\n", t);
This prints something like:
14:30:46.809059031 46
The %EX output is produced by calling std::format again with a format string
based on the locale's D_FMT, which for the C locale is something like:
%H:%M:%S. And using std::format("{:%H:%M:%S}", t) prints fractional seconds for
the %S part.
The %OS output is produced by calling std::time_put::put with the %OS format
string and a struct tm with tm_sec set to the integer number of seconds. This
doesn't print the fractional part.
If chrono::parse("%EX", t) uses std::time_get then this presents a problem for
round-tripping, as the formatted output will have fractional seconds, but the
parsed input will not consume that fractional part.
Should we consistently use std::time_put for all locale-specific output?
Alternatively, we could use time_point_cast and duration_cast to round to
seconds. None of the locale-specific formats print fractional seconds.
It would be useful to profile std::format with and without std::time_get, to
see if reusing std::format performs better. If it doesn't, using std::time_put
might be simpler.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug libstdc++/110719] Should chrono formatters always use std::time_put for locale's representation?
2023-07-18 14:43 [Bug libstdc++/110719] New: Should chrono formatters always use std::time_put for locale's representation? redi at gcc dot gnu.org
@ 2023-07-19 10:13 ` redi at gcc dot gnu.org
2023-07-19 10:37 ` redi at gcc dot gnu.org
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: redi at gcc dot gnu.org @ 2023-07-19 10:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110719
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2023-07-19
Status|UNCONFIRMED |ASSIGNED
Target Milestone|--- |13.3
Assignee|unassigned at gcc dot gnu.org |redi at gcc dot gnu.org
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug libstdc++/110719] Should chrono formatters always use std::time_put for locale's representation?
2023-07-18 14:43 [Bug libstdc++/110719] New: Should chrono formatters always use std::time_put for locale's representation? redi at gcc dot gnu.org
2023-07-19 10:13 ` [Bug libstdc++/110719] " redi at gcc dot gnu.org
@ 2023-07-19 10:37 ` redi at gcc dot gnu.org
2023-07-19 11:37 ` cvs-commit at gcc dot gnu.org
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: redi at gcc dot gnu.org @ 2023-07-19 10:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110719
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #0)
> It would be useful to profile std::format with and without std::time_get, to
s/time_get/time_put/
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug libstdc++/110719] Should chrono formatters always use std::time_put for locale's representation?
2023-07-18 14:43 [Bug libstdc++/110719] New: Should chrono formatters always use std::time_put for locale's representation? redi at gcc dot gnu.org
2023-07-19 10:13 ` [Bug libstdc++/110719] " redi at gcc dot gnu.org
2023-07-19 10:37 ` redi at gcc dot gnu.org
@ 2023-07-19 11:37 ` cvs-commit at gcc dot gnu.org
2023-07-19 11:39 ` redi at gcc dot gnu.org
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-07-19 11:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110719
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:
https://gcc.gnu.org/g:f4bce119f617dc4663fb43f55784908daf16b4b6
commit r14-2640-gf4bce119f617dc4663fb43f55784908daf16b4b6
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Tue Jul 18 12:46:07 2023 +0100
libstdc++: Implement correct locale-specific chrono formatting [PR110719]
This fixes some TODOs in the C++20 <chrono> format support, where the
locale-specific output was incorrect or unimplemented. The approach
taken here is to either use the formatting locale's std::time_put facet
to do the formatting, or to remove subsecond precision from time points
so that locale-specific formats don't print fractional seconds. This
ensures that we are consistent with what the std::time_put facet would
print (which never includes fractional seconds) even if we actually
reimplement the formatting by hand instead of using the facet.
This also fixes a misplaced statement that allowed modifiers for %Z
which should have been on %z instead. There was also some ill-formed
code in an untested branch for formatting time zone names to wide
characters. A new test for zoned_time I/O has been added to exercise
that code properly.
libstdc++-v3/ChangeLog:
PR libstdc++/110719
* include/bits/chrono_io.h (__formatter_chrono::_M_parse): Fix
allowed modifiers for %z and %Z. Fix -Wparentheses and
-Wnarrowing warnings.
(__formatter_chrono::_M_format): Call new functions for %d, %e,
%H, %I, %m and %M.
(__formatter_chrono::_M_c): Use _S_floor_seconds to remove
subsecond precision.
(__formatter_chrono::_M_C_y_Y): Use _M_locale_fmt to handle
modifiers.
(__formatter_chrono::_M_e): Replace with _M_d_e and use
_M_locale_fmt.
(__formatter_chrono::_M_I): Replace with _M_H_I and use
_M_locale_fmt.
(__formatter_chrono::_M_m): New function.
(__formatter_chrono::_M_M): New function.
(__formatter_chrono::_M_r): Use _M_locale_fmt.
(__formatter_chrono::_M_S): Likewise.
(__formatter_chrono::_M_u_w): Likewise.
(__formatter_chrono::_M_U_V_W): Likewise.
(__formatter_chrono::_M_X): Use _S_floor_seconds.
(__formatter_chrono::_M_Z): Fix untested branch for wchar_t.
(__formatter_chrono::_S_altnum): Remove function.
(__formatter_chrono::_S_dd_zero_fill): Remove function.
(__formatter_chrono::_S_floor_seconds): New function.
(__formatter_chrono::_M_locale_fmt): New function.
* testsuite/std/time/clock/system/io.cc: Adjust expected output
for locale-specific formats and check modified formats.
* testsuite/std/time/clock/utc/io.cc: Likewise.
* testsuite/std/time/zoned_time/io.cc: New test.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug libstdc++/110719] Should chrono formatters always use std::time_put for locale's representation?
2023-07-18 14:43 [Bug libstdc++/110719] New: Should chrono formatters always use std::time_put for locale's representation? redi at gcc dot gnu.org
` (2 preceding siblings ...)
2023-07-19 11:37 ` cvs-commit at gcc dot gnu.org
@ 2023-07-19 11:39 ` redi at gcc dot gnu.org
2023-07-19 15:51 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: redi at gcc dot gnu.org @ 2023-07-19 11:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110719
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #0)
> Should we consistently use std::time_put for all locale-specific output?
> Alternatively, we could use time_point_cast and duration_cast to round to
> seconds. None of the locale-specific formats print fractional seconds.
This has now been implemented on trunk.
> It would be useful to profile std::format with and without std::time_get, to
> see if reusing std::format performs better. If it doesn't, using
> std::time_put might be simpler.
This profiling would still be useful.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug libstdc++/110719] Should chrono formatters always use std::time_put for locale's representation?
2023-07-18 14:43 [Bug libstdc++/110719] New: Should chrono formatters always use std::time_put for locale's representation? redi at gcc dot gnu.org
` (3 preceding siblings ...)
2023-07-19 11:39 ` redi at gcc dot gnu.org
@ 2023-07-19 15:51 ` cvs-commit at gcc dot gnu.org
2023-07-28 17:32 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-07-19 15:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110719
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:
https://gcc.gnu.org/g:86b36e9f7e3839e923db2fda4962cd3faf2ea47b
commit r14-2646-g86b36e9f7e3839e923db2fda4962cd3faf2ea47b
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Wed Jul 19 14:38:08 2023 +0100
libstdc++: Fix locale-specific duration formatting [PR110719]
The r14-2640-gf4bce119f617dc commit only removed fractional seconds for
time points, but it needs to be done for durations and hh_mm_ss types
too.
libstdc++-v3/ChangeLog:
PR libstdc++/110719
* include/bits/chrono_io.h (__formatter_chrono::_S_floor_seconds):
Handle duration and hh_mm_ss.
* testsuite/20_util/duration/io.cc: Check locale-specific
formats.
* testsuite/std/time/hh_mm_ss/io.cc: Likewise.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug libstdc++/110719] Should chrono formatters always use std::time_put for locale's representation?
2023-07-18 14:43 [Bug libstdc++/110719] New: Should chrono formatters always use std::time_put for locale's representation? redi at gcc dot gnu.org
` (4 preceding siblings ...)
2023-07-19 15:51 ` cvs-commit at gcc dot gnu.org
@ 2023-07-28 17:32 ` cvs-commit at gcc dot gnu.org
2023-07-28 17:32 ` cvs-commit at gcc dot gnu.org
2023-07-28 18:59 ` redi at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-07-28 17:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110719
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:
https://gcc.gnu.org/g:cb01a31ab2779b0252c4945924ba2163d9150642
commit r13-7630-gcb01a31ab2779b0252c4945924ba2163d9150642
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Tue Jul 18 12:46:07 2023 +0100
libstdc++: Implement correct locale-specific chrono formatting [PR110719]
This fixes some TODOs in the C++20 <chrono> format support, where the
locale-specific output was incorrect or unimplemented. The approach
taken here is to either use the formatting locale's std::time_put facet
to do the formatting, or to remove subsecond precision from time points
so that locale-specific formats don't print fractional seconds. This
ensures that we are consistent with what the std::time_put facet would
print (which never includes fractional seconds) even if we actually
reimplement the formatting by hand instead of using the facet.
This also fixes a misplaced statement that allowed modifiers for %Z
which should have been on %z instead. There was also some ill-formed
code in an untested branch for formatting time zone names to wide
characters. A new test for zoned_time I/O has been added to exercise
that code properly.
libstdc++-v3/ChangeLog:
PR libstdc++/110719
* include/bits/chrono_io.h (__formatter_chrono::_M_parse): Fix
allowed modifiers for %z and %Z. Fix -Wparentheses and
-Wnarrowing warnings.
(__formatter_chrono::_M_format): Call new functions for %d, %e,
%H, %I, %m and %M.
(__formatter_chrono::_M_c): Use _S_floor_seconds to remove
subsecond precision.
(__formatter_chrono::_M_C_y_Y): Use _M_locale_fmt to handle
modifiers.
(__formatter_chrono::_M_e): Replace with _M_d_e and use
_M_locale_fmt.
(__formatter_chrono::_M_I): Replace with _M_H_I and use
_M_locale_fmt.
(__formatter_chrono::_M_m): New function.
(__formatter_chrono::_M_M): New function.
(__formatter_chrono::_M_r): Use _M_locale_fmt.
(__formatter_chrono::_M_S): Likewise.
(__formatter_chrono::_M_u_w): Likewise.
(__formatter_chrono::_M_U_V_W): Likewise.
(__formatter_chrono::_M_X): Use _S_floor_seconds.
(__formatter_chrono::_M_Z): Fix untested branch for wchar_t.
(__formatter_chrono::_S_altnum): Remove function.
(__formatter_chrono::_S_dd_zero_fill): Remove function.
(__formatter_chrono::_S_floor_seconds): New function.
(__formatter_chrono::_M_locale_fmt): New function.
* testsuite/std/time/clock/system/io.cc: Adjust expected output
for locale-specific formats and check modified formats.
* testsuite/std/time/clock/utc/io.cc: Likewise.
* testsuite/std/time/zoned_time/io.cc: New test.
(cherry picked from commit f4bce119f617dc4663fb43f55784908daf16b4b6)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug libstdc++/110719] Should chrono formatters always use std::time_put for locale's representation?
2023-07-18 14:43 [Bug libstdc++/110719] New: Should chrono formatters always use std::time_put for locale's representation? redi at gcc dot gnu.org
` (5 preceding siblings ...)
2023-07-28 17:32 ` cvs-commit at gcc dot gnu.org
@ 2023-07-28 17:32 ` cvs-commit at gcc dot gnu.org
2023-07-28 18:59 ` redi at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-07-28 17:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110719
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:
https://gcc.gnu.org/g:24c352c41eb944d29b09f33a42662efad3f6f811
commit r13-7631-g24c352c41eb944d29b09f33a42662efad3f6f811
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Wed Jul 19 14:38:08 2023 +0100
libstdc++: Fix locale-specific duration formatting [PR110719]
The r14-2640-gf4bce119f617dc commit only removed fractional seconds for
time points, but it needs to be done for durations and hh_mm_ss types
too.
libstdc++-v3/ChangeLog:
PR libstdc++/110719
* include/bits/chrono_io.h (__formatter_chrono::_S_floor_seconds):
Handle duration and hh_mm_ss.
* testsuite/20_util/duration/io.cc: Check locale-specific
formats.
* testsuite/std/time/hh_mm_ss/io.cc: Likewise.
(cherry picked from commit 86b36e9f7e3839e923db2fda4962cd3faf2ea47b)
^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug libstdc++/110719] Should chrono formatters always use std::time_put for locale's representation?
2023-07-18 14:43 [Bug libstdc++/110719] New: Should chrono formatters always use std::time_put for locale's representation? redi at gcc dot gnu.org
` (6 preceding siblings ...)
2023-07-28 17:32 ` cvs-commit at gcc dot gnu.org
@ 2023-07-28 18:59 ` redi at gcc dot gnu.org
7 siblings, 0 replies; 9+ messages in thread
From: redi at gcc dot gnu.org @ 2023-07-28 18:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110719
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|ASSIGNED |RESOLVED
--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed for 13.3
^ permalink raw reply [flat|nested] 9+ messages in thread
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