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<xloctime>: Fix time_get::do_get format strings for %c and %x #6133

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<xloctime>: Fix time_get::do_get format strings for %c and %x #6133

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3d43595
bug: fix `time_get::do_get` format strings for `%c` and `%x`
BrandonPacewic Mar 3, 2026
a425d31
chore: add leading zeros to test dir
BrandonPacewic Mar 3, 2026
1d99361
fix: update `P0355R7_calendars_and_time_zones_io` test inputs for `%c…
BrandonPacewic Mar 3, 2026
ffa2db1
fix: fold `GH_006129` test into `Dev11_0836436_get_time`
BrandonPacewic Mar 5, 2026
d64bcc5
fix: restore spaces in `%x` format string for consistency with `%D` a…
BrandonPacewic Mar 12, 2026
87e758c
chore: re-run ci
BrandonPacewic Mar 13, 2026
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4 changes: 2 additions & 2 deletions stl/inc/xloctime
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Original file line number Diff line number Diff line change
Expand Up @@ -453,7 +453,7 @@ protected:
break;

case 'c':
_First = _Getfmt(_First, _Last, _Iosbase, _State, _Pt, "%b %d %H : %M : %S %Y");
_First = _Getfmt(_First, _Last, _Iosbase, _State, _Pt, "%a %b %e %T %Y");
break;

case 'C':
Expand Down Expand Up @@ -547,7 +547,7 @@ protected:
break;

case 'x':
_First = _Getfmt(_First, _Last, _Iosbase, _State, _Pt, "%d / %m / %y");
_First = _Getfmt(_First, _Last, _Iosbase, _State, _Pt, "%m / %d / %y");
break;

case 'y':
Expand Down
35 changes: 31 additions & 4 deletions tests/std/tests/Dev11_0836436_get_time/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@ using namespace std;
// DevDiv-836436 "<iomanip>: get_time()'s AM/PM parsing is broken"
// DevDiv-872926 "<locale>: time_get::get parsing format string gets tm::tm_hour wrong [libcxx]"
// VSO-1259138/GH-2618 "<xloctime>: get_time does not return correct year in tm.tm_year if year is 1"
// GH-6129 "<xloctime>: time_get::do_get uses the wrong format for %c and %x"

tm helper(const char* const s, const char* const fmt) {
tm t{};
Expand Down Expand Up @@ -60,9 +61,9 @@ tuple<int, int, int> read_date(const char* const s) {
const auto t = helper(s, "%x");

// %x The date, using the locale's date format.
// "%d / %m / %y"
// %d The day of the month [01,31]; leading zeros are permitted but not required.
// "%m / %d / %y"
// %m The month number [01,12]; leading zeros are permitted but not required.
// %d The day of the month [01,31]; leading zeros are permitted but not required.
// %y The year within century. When a century is not otherwise specified,
// values in the range [69,99] shall refer to years 1969 to 1999 inclusive, and
// values in the range [00,68] shall refer to years 2000 to 2068 inclusive;
Expand Down Expand Up @@ -112,6 +113,7 @@ void test_gh_2618();
void test_gh_2848();
void test_gh_4820();
void test_gh_4882();
void test_gh_6129();

int main() {
assert(read_hour("12 AM") == 0);
Expand Down Expand Up @@ -142,9 +144,9 @@ int main() {
assert(read_hour("11 PM") == 23);
assert(read_hour("11 pm") == 23);

assert(read_date("22 / 4 / 77") == make_tuple(22, /*NOTE DIFFERENCE:*/ 3, 77));
assert(read_date("04/22/77") == make_tuple(22, /*NOTE DIFFERENCE:*/ 3, 77));

assert(read_date("22 / 4 / 11") == make_tuple(22, /*NOTE DIFFERENCE:*/ 3, /*NOTE DIFFERENCE:*/ 111));
assert(read_date("04/22/11") == make_tuple(22, /*NOTE DIFFERENCE:*/ 3, /*NOTE DIFFERENCE:*/ 111));

assert(read_time("15 : 47 : 58") == make_tuple(15, 47, 58));
Comment on lines -145 to 149
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@MattStephanson MattStephanson Mar 13, 2026

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I'd also update the test to put the whitespace back in, to make sure that the parser accepts it. Sorry I neglected to mention it earlier. But otherwise LGTM, thanks!


Expand All @@ -160,6 +162,7 @@ int main() {
test_gh_2848();
test_gh_4820();
test_gh_4882();
test_gh_6129();
}

typedef istreambuf_iterator<char> Iter;
Expand Down Expand Up @@ -910,6 +913,30 @@ void test_gh_4820() {
}
}

void test_gh_6129() {
// GH-6129 "<xloctime>: time_get::do_get uses the wrong format for %c and %x"

// %c in the C locale uses "%a %b %e %T %Y"
{
const auto t = helper("Thu Jun 6 09:49:10 2009", "%c");
assert(t.tm_wday == 4);
assert(t.tm_mon == 5);
assert(t.tm_mday == 6);
assert(t.tm_hour == 9);
assert(t.tm_min == 49);
assert(t.tm_sec == 10);
assert(t.tm_year == 109);
}

// %x in the C locale uses "%m / %d / %y"
{
const auto t = helper("03/15/09", "%x");
assert(t.tm_mon == 2);
assert(t.tm_mday == 15);
assert(t.tm_year == 109);
}
}

void test_gh_4882() {
// GH-4882 <iomanip>: std::put_time should not crash on invalid/out-of-range tm struct values
const auto fieldValidation = [](int tm::* const field, const int value, const string& fmt) {
Expand Down
96 changes: 48 additions & 48 deletions tests/std/tests/P0355R7_calendars_and_time_zones_io/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -639,10 +639,10 @@ void parse_calendar_types_basic() {
// basic %D test
test_parse("07/04/76 17", "%D %C", ymd);
assert(ymd == July / 4d / 1776y);
// locale's date representation %x (== "%d / %m / %y")
test_parse("04/07/76 17", "%x %C", ymd);
// locale's date representation %x (== "%m / %d / %y")
test_parse("07/04/76 17", "%x %C", ymd);
assert(ymd == 4d / July / 1776y);
test_parse("10/12/15 18", "%x %C", ymd);
test_parse("12/10/15 18", "%x %C", ymd);
assert(ymd == 10d / December / 1815y);

// day-of-year tests, leap and non-leap years
Expand Down Expand Up @@ -972,27 +972,27 @@ void parse_timepoints() {
file_time<seconds> ft;
local_seconds lt;

test_parse("oct 29 19:01:42 2020", "%c", st);
test_parse("oct 29 19:01:42 2020", "%c", ut);
test_parse("oct 29 19:01:42 2020", "%c", ft);
test_parse("oct 29 19:01:42 2020", "%c", lt);
test_parse("thu oct 29 19:01:42 2020", "%c", st);
test_parse("thu oct 29 19:01:42 2020", "%c", ut);
test_parse("thu oct 29 19:01:42 2020", "%c", ft);
test_parse("thu oct 29 19:01:42 2020", "%c", lt);

assert(st == ref);
assert(ut == clock_cast<utc_clock>(ref));
assert(ft == clock_cast<file_clock>(ref));
assert(lt.time_since_epoch() == ref.time_since_epoch());

minutes offset;
test_parse("oct 29 19:01:42 2020 0430", "%c %z", st, nullptr, &offset);
test_parse("thu oct 29 19:01:42 2020 0430", "%c %z", st, nullptr, &offset);
assert(st == ref - offset && offset == 4h + 30min);

test_parse("oct 29 19:01:42 2020 0430", "%c %z", ut, nullptr, &offset);
test_parse("thu oct 29 19:01:42 2020 0430", "%c %z", ut, nullptr, &offset);
assert(ut == clock_cast<utc_clock>(ref) - offset && offset == 4h + 30min);

test_parse("oct 29 19:01:42 2020 0430", "%c %z", ft, nullptr, &offset);
test_parse("thu oct 29 19:01:42 2020 0430", "%c %z", ft, nullptr, &offset);
assert(ft == clock_cast<file_clock>(ref) - offset && offset == 4h + 30min);

test_parse("oct 29 19:01:42 2020 0430", "%c %z", lt, nullptr, &offset);
test_parse("thu oct 29 19:01:42 2020 0430", "%c %z", lt, nullptr, &offset);
assert(lt.time_since_epoch() == ref.time_since_epoch() && offset == 4h + 30min);

// N4878 [time.clock.tai]/1:
Expand All @@ -1004,13 +1004,13 @@ void parse_timepoints() {

ref = sys_days{1957y / December / 31d} + days{1} - 10s;
tai_seconds tt;
test_parse("jan 1 00:00:00 1958", "%c", tt);
test_parse("wed jan 1 00:00:00 1958", "%c", tt);
assert(tt == clock_cast<tai_clock>(ref));

ref = sys_days{2000y / January / 1d};
test_parse("jan 1 00:00:32 2000", "%c", tt);
test_parse("sat jan 1 00:00:32 2000", "%c", tt);
assert(tt == clock_cast<tai_clock>(ref));
test_parse("jan 1 00:00:32 2000 0430", "%c %z", tt, nullptr, &offset);
test_parse("sat jan 1 00:00:32 2000 0430", "%c %z", tt, nullptr, &offset);
assert(tt == clock_cast<tai_clock>(ref) - offset && offset == 4h + 30min);

// N4878 [time.clock.gps]/1:
Expand All @@ -1022,11 +1022,11 @@ void parse_timepoints() {

gps_seconds gt;
ref = sys_days{1980y / January / 6d};
test_parse("jan 6 00:00:00 1980 0430", "%c %z", gt, nullptr, &offset);
test_parse("sun jan 6 00:00:00 1980 0430", "%c %z", gt, nullptr, &offset);
assert(gt == clock_cast<gps_clock>(ref) - offset && offset == 4h + 30min);
test_parse("jan 6 00:00:00 1980", "%c", gt);
test_parse("sun jan 6 00:00:00 1980", "%c", gt);
assert(gt == clock_cast<gps_clock>(ref));
test_parse("jan 6 00:00:19 1980", "%c", tt);
test_parse("sun jan 6 00:00:19 1980", "%c", tt);
assert(gt == clock_cast<gps_clock>(tt));

seconds time;
Expand Down Expand Up @@ -1074,75 +1074,75 @@ void parse_timepoints() {
}

utc_seconds ut_ref = utc_clock::from_sys(sys_days{1d / July / 1972y}) - 1s; // leap second insertion
test_parse("june 30 23:59:60 1972", "%c", ut);
test_parse("fri june 30 23:59:60 1972", "%c", ut);
assert(ut == ut_ref);

// Test a later leap second, where the accumulated offset is greater than 1s.
ut_ref = utc_clock::from_sys(sys_days{1d / July / 1992y}) - 1s;
test_parse("june 30 23:59:60 1992", "%c", ut);
test_parse("tue june 30 23:59:60 1992", "%c", ut);
assert(ut == ut_ref);

// not leap-second aware
fail_parse("june 30 23:59:60 1972", "%c", st);
fail_parse("june 30 23:59:60 1972", "%c", tt);
fail_parse("june 30 23:59:60 1972", "%c", gt);
fail_parse("june 30 23:59:60 1972", "%c", ft);
fail_parse("fri june 30 23:59:60 1972", "%c", st);
fail_parse("fri june 30 23:59:60 1972", "%c", tt);
fail_parse("fri june 30 23:59:60 1972", "%c", gt);
fail_parse("fri june 30 23:59:60 1972", "%c", ft);

fail_parse("june 30 23:59:60 1973", "%c", ut); // not a leap second insertion
fail_parse("sat june 30 23:59:60 1973", "%c", ut); // not a leap second insertion

// the last leap second insertion that file_clock is not aware of
test_parse("dec 31 23:59:59 2016", "%c", ut);
test_parse("dec 31 23:59:59 2016", "%c", ft);
test_parse("sat dec 31 23:59:59 2016", "%c", ut);
test_parse("sat dec 31 23:59:59 2016", "%c", ft);
assert(ft == clock_cast<file_clock>(ut));

test_parse("dec 31 23:59:60 2016", "%c", ut);
fail_parse("dec 31 23:59:60 2016", "%c", ft);
test_parse("sat dec 31 23:59:60 2016", "%c", ut);
fail_parse("sat dec 31 23:59:60 2016", "%c", ft);

test_parse("jan 01 00:00:00 2017", "%c", ut);
test_parse("jan 01 00:00:00 2017", "%c", ft);
test_parse("sun jan 01 00:00:00 2017", "%c", ut);
test_parse("sun jan 01 00:00:00 2017", "%c", ft);
assert(ft == clock_cast<file_clock>(ut));

ref = sys_days{1d / January / 2020y} - 1s; // negative leap second, UTC time doesn't exist
fail_parse("dec 31 23:59:59 2019", "%c", ut);
fail_parse("dec 31 23:59:59 2019", "%c", ft);
fail_parse("tue dec 31 23:59:59 2019", "%c", ut);
fail_parse("tue dec 31 23:59:59 2019", "%c", ft);

test_parse("dec 31 23:59:59 2019", "%c", st);
test_parse("tue dec 31 23:59:59 2019", "%c", st);
assert(st == ref);

test_parse("dec 31 23:59:59 2019", "%c", lt); // Not UTC, might be valid depending on the time zone.
test_parse("tue dec 31 23:59:59 2019", "%c", lt); // Not UTC, might be valid depending on the time zone.
assert(lt.time_since_epoch() == ref.time_since_epoch());

// Initially, TAI - UTC == 37s.
test_parse("dec 31 23:59:59 2019", "%c", tt);
test_parse("dec 31 23:59:22 2019", "%c", ut);
test_parse("tue dec 31 23:59:59 2019", "%c", tt);
test_parse("tue dec 31 23:59:22 2019", "%c", ut);
assert(tt == clock_cast<tai_clock>(ut));

test_parse("jan 01 00:00:35 2020", "%c", tt);
test_parse("dec 31 23:59:58 2019", "%c", ut);
test_parse("wed jan 01 00:00:35 2020", "%c", tt);
test_parse("tue dec 31 23:59:58 2019", "%c", ut);
assert(tt == clock_cast<tai_clock>(ut));

test_parse("jan 01 00:00:36 2020", "%c", tt);
test_parse("jan 01 00:00:00 2020", "%c", ut);
test_parse("wed jan 01 00:00:36 2020", "%c", tt);
test_parse("wed jan 01 00:00:00 2020", "%c", ut);
assert(tt == clock_cast<tai_clock>(ut));

// Initially, GPS - UTC == 18s
test_parse("dec 31 23:59:59 2019", "%c", gt);
test_parse("dec 31 23:59:41 2019", "%c", ut);
test_parse("tue dec 31 23:59:59 2019", "%c", gt);
test_parse("tue dec 31 23:59:41 2019", "%c", ut);
assert(gt == clock_cast<gps_clock>(ut));

test_parse("jan 01 00:00:16 2020", "%c", gt);
test_parse("dec 31 23:59:58 2019", "%c", ut);
test_parse("wed jan 01 00:00:16 2020", "%c", gt);
test_parse("tue dec 31 23:59:58 2019", "%c", ut);
assert(gt == clock_cast<gps_clock>(ut));

test_parse("jan 01 00:00:17 2020", "%c", gt);
test_parse("jan 01 00:00:00 2020", "%c", ut);
test_parse("wed jan 01 00:00:17 2020", "%c", gt);
test_parse("wed jan 01 00:00:00 2020", "%c", ut);
assert(gt == clock_cast<gps_clock>(ut));


ut_ref = utc_clock::from_sys(sys_days{1d / January / 2022y}) - 1s; // leap second insertion
test_parse("dec 31 23:59:60 2021", "%c", ut);
test_parse("fri dec 31 23:59:60 2021", "%c", ut);
assert(ut == ut_ref);
test_parse("dec 31 23:59:60 2021", "%c", ft);
test_parse("fri dec 31 23:59:60 2021", "%c", ft);
assert(ft == clock_cast<file_clock>(ut_ref));


Expand Down