формат даты и времени (format date and time)
Примечание (Note)
ISO 8601 week dates
%G, %g, and %V yield values calculated from the week-based year
defined by the ISO 8601 standard. In this system, weeks start on
a Monday, and are numbered from 01, for the first week, up to 52
or 53, for the last week. Week 1 is the first week where four or
more days fall within the new year (or, synonymously, week 01 is:
the first week of the year that contains a Thursday; or, the week
that has 4 January in it). When three or fewer days of the first
calendar week of the new year fall within that year, then the ISO
8601 week-based system counts those days as part of week 52 or 53
of the preceding year. For example, 1 January 2010 is a Friday,
meaning that just three days of that calendar week fall in 2010.
Thus, the ISO 8601 week-based system considers these days to be
part of week 53 (%V) of the year 2009 (%G); week 01 of ISO 8601
year 2010 starts on Monday, 4 January 2010. Similarly, the first
two days of January 2011 are considered to be part of week 52 of
the year 2010.
Glibc notes
Glibc provides some extensions for conversion specifications.
(These extensions are not specified in POSIX.1-2001, but a few
other systems provide similar features.) Between the '%'
character and the conversion specifier character, an optional
flag and field width may be specified. (These precede the E or O
modifiers, if present.)
The following flag characters are permitted:
_ (underscore) Pad a numeric result string with spaces.
- (dash) Do not pad a numeric result string.
0 Pad a numeric result string with zeros even if the
conversion specifier character uses space-padding by
default.
^ Convert alphabetic characters in result string to
uppercase.
# Swap the case of the result string. (This flag works only
with certain conversion specifier characters, and of
these, it is only really useful with %Z.)
An optional decimal width specifier may follow the (possibly
absent) flag. If the natural size of the field is smaller than
this width, then the result string is padded (on the left) to the
specified width.
