NEWSTRFTIME(3)             Library Functions Manual             NEWSTRFTIME(3)

NAME
       strftime - format date and time

SYNOPSIS
       #include <time.h>

       size_t strftime(char *restrict buf, size_t maxsize,
           char const *restrict format, struct tm const *restrict timeptr);

       cc ... -ltz

DESCRIPTION
       The strftime function formats the information from timeptr into the
       array pointed to by buf according to the string pointed to by format.

       The format string consists of zero or more conversion specifications
       and ordinary characters.  All ordinary characters are copied directly
       into the array.  A conversion specification consists of a percent sign
       and one other character.

       No more than maxsize bytes are placed into the array.

       Each conversion specification is replaced by the characters as follows
       which are then copied into the array.

       %A     is replaced by the locale's full weekday name.

       %a     is replaced by the locale's abbreviated weekday name.

       %B     is replaced by the locale's full month name.

       %b or %h
              is replaced by the locale's abbreviated month name.

       %C     is replaced by the century (a year divided by 100 and truncated
              to an integer) as a decimal number [00,99].

       %c     is replaced by the locale's appropriate date and time
              representation.

       %D     is equivalent to %m/%d/%y.

       %d     is replaced by the day of the month as a decimal number [01,31].

       %e     is replaced by the day of month as a decimal number [1,31];
              single digits are preceded by a blank.

       %F     is equivalent to %Y-%m-%d (the ISO 8601 date format).

       %G     is replaced by the ISO 8601 year with century as a decimal
              number.  See also the %V conversion specification.

       %g     is replaced by the ISO 8601 year without century as a decimal
              number [00,99].  This is the year that includes the greater part
              of the week.  (Monday as the first day of a week).  See also the
              %V conversion specification.

       %H     is replaced by the hour (24-hour clock) as a decimal number
              [00,23].

       %I     is replaced by the hour (12-hour clock) as a decimal number
              [01,12].

       %j     is replaced by the day of the year as a decimal number
              [001,366].

       %k     is replaced by the hour (24-hour clock) as a decimal number
              [0,23]; single digits are preceded by a blank.

       %l     is replaced by the hour (12-hour clock) as a decimal number
              [1,12]; single digits are preceded by a blank.

       %M     is replaced by the minute as a decimal number [00,59].

       %m     is replaced by the month as a decimal number [01,12].

       %n     is replaced by a newline.

       %p     is replaced by the locale's equivalent of either "AM" or "PM".

       %R     is replaced by the time in the format %H:%M.

       %r     is replaced by the locale's representation of 12-hour clock time
              using AM/PM notation.

       %S     is replaced by the second as a decimal number [00,60].  The
              range of seconds is [00,60] instead of [00,59] to allow for the
              periodic occurrence of leap seconds.

       %s     is replaced by the number of seconds since the Epoch (see
              ctime(3)).

       %T     is replaced by the time in the format %H:%M:%S.

       %t     is replaced by a tab.

       %U     is replaced by the week number of the year (Sunday as the first
              day of the week) as a decimal number [00,53].

       %u     is replaced by the weekday (Monday as the first day of the week)
              as a decimal number [1,7].

       %V     is replaced by the week number of the year (Monday as the first
              day of the week) as a decimal number [01,53].  If the week
              containing January 1 has four or more days in the new year, then
              it is week 1; otherwise it is week 53 of the previous year, and
              the next week is week 1.  The year is given by the %G conversion
              specification.

       %W     is replaced by the week number of the year (Monday as the first
              day of the week) as a decimal number [00,53].

       %w     is replaced by the weekday (Sunday as the first day of the week)
              as a decimal number [0,6].

       %X     is replaced by the locale's appropriate time representation.

       %x     is replaced by the locale's appropriate date representation.

       %Y     is replaced by the year with century as a decimal number.

       %y     is replaced by the year without century as a decimal number
              [00,99].

       %Z     is replaced by the time zone abbreviation, or by the empty
              string if this is not determinable.

       %z     is replaced by the offset from the Prime Meridian in the format
              +HHMM or -HHMM (ISO 8601) as appropriate, with positive values
              representing locations east of Greenwich, or by the empty string
              if this is not determinable.  The numeric time zone abbreviation
              -0000 is used when the time is Universal Time but local time is
              indeterminate; by convention this is used for locations while
              uninhabited, and corresponds to a zero offset when the time zone
              abbreviation begins with "-".

       %%     is replaced by a single %.

       %+     is replaced by the locale's date and time in date(1) format.

RETURN VALUE
       If the conversion is successful, strftime returns the number of bytes
       placed into the array, not counting the terminating NUL; errno is
       unchanged if the returned value is zero.  Otherwise, errno is set to
       indicate the error, zero is returned, and the array contents are
       unspecified.

ERRORS
       This function fails if:

       [ERANGE]
              The total number of resulting bytes, including the terminating
              NUL character, is more than maxsize.

       This function may fail if:

       [EOVERFLOW]
              The format includes an %s conversion and the number of seconds
              since the Epoch cannot be represented in a time_t.

SEE ALSO
       date(1), getenv(3), newctime(3), newtzset(3), time(2), tzfile(5)

BUGS
       There is no conversion specification for the phase of the moon.

                                                                NEWSTRFTIME(3)
