Module product_os_async_executor::format::strftime

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Expand description

strftime/strptime-inspired date and time formatting syntax.

§Specifiers

The following specifiers are available both to formatting and parsing.

Spec.ExampleDescription
DATE SPECIFIERS:
%Y2001The full proleptic Gregorian year, zero-padded to 4 digits. chrono supports years from -262144 to 262143. Note: years before 1 BCE or after 9999 CE, require an initial sign (+/-).
%C20The proleptic Gregorian year divided by 100, zero-padded to 2 digits. 1
%y01The proleptic Gregorian year modulo 100, zero-padded to 2 digits. 1
%m07Month number (01–12), zero-padded to 2 digits.
%bJulAbbreviated month name. Always 3 letters.
%BJulyFull month name. Also accepts corresponding abbreviation in parsing.
%hJulSame as %b.
%d08Day number (01–31), zero-padded to 2 digits.
%e 8Same as %d but space-padded. Same as %_d.
%aSunAbbreviated weekday name. Always 3 letters.
%ASundayFull weekday name. Also accepts corresponding abbreviation in parsing.
%w0Sunday = 0, Monday = 1, …, Saturday = 6.
%u7Monday = 1, Tuesday = 2, …, Sunday = 7. (ISO 8601)
%U28Week number starting with Sunday (00–53), zero-padded to 2 digits. 2
%W27Same as %U, but week 1 starts with the first Monday in that year instead.
%G2001Same as %Y but uses the year number in ISO 8601 week date. 3
%g01Same as %y but uses the year number in ISO 8601 week date. 3
%V27Same as %U but uses the week number in ISO 8601 week date (01–53). 3
%j189Day of the year (001–366), zero-padded to 3 digits.
%D07/08/01Month-day-year format. Same as %m/%d/%y.
%x07/08/01Locale’s date representation (e.g., 12/31/99).
%F2001-07-08Year-month-day format (ISO 8601). Same as %Y-%m-%d.
%v 8-Jul-2001Day-month-year format. Same as %e-%b-%Y.
TIME SPECIFIERS:
%H00Hour number (00–23), zero-padded to 2 digits.
%k 0Same as %H but space-padded. Same as %_H.
%I12Hour number in 12-hour clocks (01–12), zero-padded to 2 digits.
%l12Same as %I but space-padded. Same as %_I.
%Pamam or pm in 12-hour clocks.
%pAMAM or PM in 12-hour clocks.
%M34Minute number (00–59), zero-padded to 2 digits.
%S60Second number (00–60), zero-padded to 2 digits. 4
%f26490000Number of nanoseconds since last whole second. 5
%.f.026490Decimal fraction of a second. Consumes the leading dot. 5
%.3f.026Decimal fraction of a second with a fixed length of 3.
%.6f.026490Decimal fraction of a second with a fixed length of 6.
%.9f.026490000Decimal fraction of a second with a fixed length of 9.
%3f026Decimal fraction of a second like %.3f but without the leading dot.
%6f026490Decimal fraction of a second like %.6f but without the leading dot.
%9f026490000Decimal fraction of a second like %.9f but without the leading dot.
%R00:34Hour-minute format. Same as %H:%M.
%T00:34:60Hour-minute-second format. Same as %H:%M:%S.
%X00:34:60Locale’s time representation (e.g., 23:13:48).
%r12:34:60 AMLocale’s 12 hour clock time. (e.g., 11:11:04 PM). Falls back to %X if the locale does not have a 12 hour clock format.
TIME ZONE SPECIFIERS:
%ZACSTLocal time zone name. Skips all non-whitespace characters during parsing. Identical to %:z when formatting. 6
%z+0930Offset from the local time to UTC (with UTC being +0000).
%:z+09:30Same as %z but with a colon.
%::z+09:30:00Offset from the local time to UTC with seconds.
%:::z+09Offset from the local time to UTC without minutes.
%#z+09Parsing only: Same as %z but allows minutes to be missing or present.
DATE & TIME SPECIFIERS:
%cSun Jul 8 00:34:60 2001Locale’s date and time (e.g., Thu Mar 3 23:05:25 2005).
%+2001-07-08T00:34:60.026490+09:30ISO 8601 / RFC 3339 date & time format. 7
%s994518299UNIX timestamp, the number of seconds since 1970-01-01 00:00 UTC. 8
SPECIAL SPECIFIERS:
%tLiteral tab (\t).
%nLiteral newline (\n).
%%Literal percent sign.

It is possible to override the default padding behavior of numeric specifiers %?. This is not allowed for other specifiers and will result in the BAD_FORMAT error.

ModifierDescription
%-?Suppresses any padding including spaces and zeroes. (e.g. %j = 012, %-j = 12)
%_?Uses spaces as a padding. (e.g. %j = 012, %_j = 12)
%0?Uses zeroes as a padding. (e.g. %e = 9, %0e = 09)

Notes:

  1. %C, %y: This is floor division, so 100 BCE (year number -99) will print -1 and 99 respectively. ↩

  2. %U: Week 1 starts with the first Sunday in that year. It is possible to have week 0 for days before the first Sunday. ↩

  3. %G, %g, %V: Week 1 is the first week with at least 4 days in that year. Week 0 does not exist, so this should be used with %G or %g. ↩

  4. %S: It accounts for leap seconds, so 60 is possible. ↩

  5. %f, %.f:
    %f and %.f are notably different formatting specifiers.
    %f counts the number of nanoseconds since the last whole second, while %.f is a fraction of a second.
    Example: 7μs is formatted as 7000 with %f, and formatted as .000007 with %.f. ↩

  6. %Z: Since chrono is not aware of timezones beyond their offsets, this specifier only prints the offset when used for formatting. The timezone abbreviation will NOT be printed. See this issue for more information.

    Offset will not be populated from the parsed data, nor will it be validated. Timezone is completely ignored. Similar to the glibc strptime treatment of this format code.

    It is not possible to reliably convert from an abbreviation to an offset, for example CDT can mean either Central Daylight Time (North America) or China Daylight Time. ↩

  7. %+: Same as %Y-%m-%dT%H:%M:%S%.f%:z, i.e. 0, 3, 6 or 9 fractional digits for seconds and colons in the time zone offset.

    This format also supports having a Z or UTC in place of %:z. They are equivalent to +00:00.

    Note that all T, Z, and UTC are parsed case-insensitively.

    The typical strftime implementations have different (and locale-dependent) formats for this specifier. While Chrono’s format for %+ is far more stable, it is best to avoid this specifier if you want to control the exact output. ↩

  8. %s: This is not padded and can be negative. For the purpose of Chrono, it only accounts for non-leap seconds so it slightly differs from ISO C strftime behavior. ↩

Structs§