strftime(3)                                                 strftime(3)

  strftime()

  NAME

    strftime() - format date and time

  SYNOPSIS

    #include 

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

  DESCRIPTION

    The strftime(3) function formats the information from timeptr into the
    buffer 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
    buffer. A conversion specification consists of a percent sign % and one
    other character.

    No more than maxsize characters will be placed into the array. If the
    total number of resulting characters, including the terminating \0
    character, is not more than maxsize, strftime(3) returns the number of
    characters in the array, not counting the terminating NUL. Otherwise, zero
    is returned.

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

    %A
        is replaced by the full weekday name in the current locale.

    %a
        is replaced by the weekday name abbreviated for the current locale. In
        the C and POSIX locales, this is the first three characters of the
        full weekday name.

    %B
        is replaced by the full month name in the current locale.

    %b
        is replaced by the abbreviated month name for the current locale. In
        the C and POSIX locales, thisis the first three characters of the full
        month name.

    %C
        is replaced by the century number, in the range from 00-99; for
        example, dates from 1900-1999 are converted to 19.

    %c
        the locale's date and time representation; in the POSIX locale, the
        same as %m/%d/%y.

    %D
        is replaced by the date in the format mm/dd/yy (similar 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.

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

    %h
        is identical to %b.

    %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 either AM or PM as appropriate.

    %R
        is equivalent to %H:%M

    %r
        is the 12-hour clock time using the AM/PM notation of the current
        locale, if t_fmt_ampm is not an empty string in the LC_TIME portion of
        the current locale. In the POSIX locale, this will be equivalent to
        %I:%M:%S %p.

    %t
        is replaced by a tab.

    %S
        is replaced by the second as a decimal number (00-60).

    %T or %X
        is equivalent to %H:%M:%S.

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

    %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 equivalent to %m/%d/%y%H:%M:%S

    %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 name.

    %%
        is replaced by %.

    Some of the directives can be modified by the characters E and O to
    indicate that they use an alternative format or specification. (For
    locales where this alternative specification doesn't exist, strftime(3)
    behaves as if the modifying E or O weren't present.)

    %Ec
        The alternative appropriate representative for the date and time.

    %EC
        The name of the base year (or time period) in the alternative
        representation for the locale.

    %Ex
        The alternative date representation for the locale.

    %EX
        The alternative time representation for the locale.

    %Ey
        The offset from the year (%EC) in the alternative representation of
        the year.

    %EY
        The full year representation in the locale's alternative
        representation.

    %Od
        The day of the month in the alternative representation of the locale.
        Leading zeroes are permitted but not required.

    %Oe
        The same as %Od.

    %OH
        The hour in the 24-hour clock using the alternative numeric symbols of
        the locale.

    %OI
        The hour in the 12-hour clock using the alternative numeric symbols of
        the locale.

    %Om
        The month using the alternative numeric symbols of the locale.

    %OM
        The minutes using the alternative numeric symbols of the locale.

    %OS
        The seconds using the alternative numeric symbols of the locale.

    %Ou
        The week of the year as a number, using the alternative numeric
        symbols of the locale (Monday=1).

    %OU
        The week of the year as a number, using the alternative numeric
        symbols of the locale. Sunday is considered the first day of the week.

    %OV
        The week of the year as a number, using the alternative numeric
        symbols of the locale. Monday is considered the first day of the week.

    %Ow
        The day of the week as a number using the alternative numeric symbols
        of the locale. Sunday is considered day 0.

    %OW
        The week of the year as a number, using the alternative numeric
        symbols of the locale. Monday is considered the first day of the week.

    %Oy
        The year, offset from %C, using the alternative numeric symbols of the
        locale.

  SEE ALSO

    printf(1)

    date(1)

    ctime(3)

    printf(3)

  USAGE NOTES

    The strftime function is thread safe.

    The strftime function is not async-signal safe.