strftime(3C)                                               Standard C Library Functions                                               strftime(3C)

NAME

       strftime, cftime, ascftime - convert date and time to string

SYNOPSIS

       #include <time.h>

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

       int cftime(char *s, char *format, const time_t *clock);

       int ascftime(char *s, const char *format, const struct tm *timeptr);

DESCRIPTION

       The  strftime(),  ascftime(),  and  cftime() functions place bytes into the array pointed to by s as controlled by the string pointed to by
       format. The format string consists of zero or more conversion specifications and ordinary characters.  A conversion specification  consists
       of  a '%' (percent) character and one or two terminating conversion characters that determine the conversion specification's behavior.  All
       ordinary characters (including the terminating null byte) are copied unchanged into the array pointed to  by  s.  If  copying  takes  place
       between objects that overlap, the behavior is undefined. For strftime (), no more than maxsize bytes are placed into the array.

       If  format  is  (char  *)0, then the locale's default format is used. For strftime() the default format is the same as %c; for cftime() and
       ascftime() the default format is the same as %C. cftime() and ascftime() first try to use the value of the environment variable CFTIME, and
       if that is undefined or empty, the default format is used.

       Each  conversion  specification  is  replaced  by appropriate characters as described in the following list. The appropriate characters are
       determined by the LC_TIME category of the program's locale and by the values contained in the structure pointed to  by  timeptr  for  strf-
       time() and ascftime(), and by the time represented by clock for cftime().

       %%       Same as %.

       %a       Locale's abbreviated weekday name.

       %A       Locale's full weekday name.

       %b       Locale's abbreviated month name.

       %B       Locale's full month name.

       %c       Locale's appropriate date and time representation.

   Default
       %C       Locale's date and time representation as produced by date(1).

   Standard conforming
       %C       Century  number (the year divided by 100 and truncated to an integer as a decimal number [1,99]); single digits are preceded by 0;
                see standards(5).

       %d       Day of month [1,31]; single digits are preceded by 0.

       %D       Date as %m/%d/%y.

       %e       Day of month [1,31]; single digits are preceded by a space.

       %F       Equivalent to %Y-%m-%d (the ISO 8601:2000 standard date format).

       %g       Week-based year within century [00,99].

       %G       Week-based year, including the century [0000,9999].

       %h       Locale's abbreviated month name.

       %H       Hour (24-hour clock) [0,23]; single digits are preceded by 0.

       %I       Hour (12-hour clock) [1,12]; single digits are preceded by 0.

       %j       Day number of year [1,366]; single digits are preceded by 0.

       %k       Hour (24-hour clock) [0,23]; single digits are preceded by a blank.

       %l       Hour (12-hour clock) [1,12]; single digits are preceded by a blank.

       %m       Month number [1,12]; single digits are preceded by 0.

       %M       Minute [00,59]; leading 0 is permitted but not required.

       %n       Insert a NEWLINE.

       %p       Locale's equivalent of either a.m. or p.m.

       %r       Appropriate time representation in 12-hour clock format with %p.

       %R       Time as %H:%M.

       %S       Seconds [00,60]; the range of values is [00,60] rather than [00,59] to allow for the occasional leap second and  even  more  occa-
                sional double leap second.

       %t       Insert a TAB.

       %T       Time as %H:%M:%S.

       %u       Weekday as a decimal number [1,7], with 1 representing Monday. See NOTES below.

       %U       Week number of year as a decimal number [00,53], with Sunday as the first day of week 1.

       %V       The ISO 8601 week number as a decimal number [01,53]. In the ISO 8601 week-based system, weeks begin on a Monday and week 1 of the
                year is the week that includes both January 4th and the first Thursday of the year.  If the first Monday of January  is  the  2nd,
                3rd, or 4th, the preceding days are part of the last week of the preceding year.  See NOTES below.

       %w       Weekday as a decimal number [0,6], with 0 representing Sunday.

       %W       Week number of year as a decimal number [00,53], with Monday as the first day of week 1.

       %x       Locale's appropriate date representation.

       %X       Locale's appropriate time representation.

       %y       Year within century [00,99].

       %Y       Year, including the century (for example 1993).

       %z       Replaced by offset from UTC in ISO 8601:2000 standard format (+hhmm or -hhmm), or by no characters if no timezone is determinable.
                For example, "-0430" means 4 hours 30 minutes behind UTC (west of Greenwich).  If tm_isdst is zero, the standard  time  offset  is
                used.   If  tm_isdst  is  greater  than zero, the daylight savings time offset if used. If tm_isdst is negative, no characters are
                returned.

       %Z       Time zone name or abbreviation, or no bytes if no time zone information exists.

       If a conversion specification does not correspond to any of the above or to any of the modified conversion specifications listed below, the
       behavior is undefined and 0 is returned.

       The  difference  between  %U  and  %W (and also between modified conversion specifications %OU and %OW) lies in which day is counted as the
       first of the week. Week number 1 is the first week in January starting with a Sunday for %U or a Monday for  %W.  Week  number  0  contains
       those days before the first Sunday or Monday in January for %U and %W, respectively.

   Modified Conversion Specifications
       Some  conversion  specifications  can  be modified by the E and O modifiers to indicate that an alternate format or specification should be
       used rather than the one normally used by the unmodified conversion specification. If the alternate format or specification does not  exist
       in the current locale, the behavior will be as if the unmodified specification were used.

       %Ec      Locale's alternate appropriate date and time representation.

       %EC      Name of the base year (period) in the locale's alternate representation.

       %Eg      Offset from %EC of the week-based year in the locale's alternative representation.

       %EG      Full alternative representation of the week-based year.

       %Ex      Locale's alternate date representation.

       %EX      Locale's alternate time representation.

       %Ey      Offset from %EC (year only) in the locale's alternate representation.

       %EY      Full alternate year representation.

       %Od      Day of the month using the locale's alternate numeric symbols.

       %Oe      Same as %Od.

       %Og      Week-based year (offset from %C) in the locale's alternate representation and using the locale's alternate numeric symbols.

       %OH      Hour (24-hour clock) using the locale's alternate numeric symbols.

       %OI      Hour (12-hour clock) using the locale's alternate numeric symbols.

       %Om      Month using the locale's alternate numeric symbols.

       %OM      Minutes using the locale's alternate numeric symbols.

       %OS      Seconds using the locale's alternate numeric symbols.

       %Ou      Weekday as a number in the locale's alternate numeric symbols.

       %OU      Week number of the year (Sunday as the first day of the week) using the locale's alternate numeric symbols.

       %Ow      Number of the weekday (Sunday=0) using the  locale's alternate numeric symbols.

       %OW      Week number of the year (Monday as the first day of the week) using the locale's alternate numeric symbols.

       %Oy      Year (offset from %C) in the locale's alternate representation and using the locale's alternate numeric symbols.

   Selecting the Output Language
       By  default, the output of strftime(), cftime(), and ascftime() appear in U.S. English. The user can request that the output of strftime(),
       cftime(), or ascftime() be in a specific language by setting the LC_TIME category using setlocale().

   Time Zone
       Local time zone information is used as though tzset(3C) were called.

RETURN VALUES

       The strftime(), cftime(), and ascftime() functions return the number of characters placed into the array pointed to by s, not including the
       terminating  null  character.  If  the  total number of resulting characters including the terminating null character is more than maxsize,
       strftime() returns 0 and the contents of the array are indeterminate.

EXAMPLES

       Example 1: An example of the strftime() function.

       The following example illustrates the use of strftime() for the POSIX locale. It shows what the string in str would look like if the struc-
       ture pointed to by tmptr contains the values corresponding to Thursday, August 28, 1986 at 12:44:36.

       strftime (str, strsize, "%A %b %d %j", tmptr)

       This results in str containing "Thursday Aug 28 240".

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE         |      ATTRIBUTE VALUE        |
       |MT-Level                     |MT-Safe                      |
       |CSI                          |Enabled                      |
       |Interface Stability          |strftime() is Standard.      |
       +-----------------------------+-----------------------------+

SEE ALSO

       date(1), ctime(3C), mktime(3C), setlocale(3C), strptime(3C), tzset(3C), TIMEZONE(4), zoneinfo(4), attributes(5), environ(5), standards(5)

NOTES

       The  conversion  specification for %V was changed in the Solaris 7 release. This change was based on the public review draft of the ISO C9x
       standard at that time. Previously, the specification stated that if the week containing 1 January had fewer than four days in the new year,
       it became week 53 of the previous year. The ISO C9x standard committee subsequently recognized that that specification had been incorrect.

       The  conversion  specifications  for  %g,  %G,  %Eg, %EG, and %Og were added in the Solaris 7 release.  This change was based on the public
       review draft of the ISO C9x standard at that time. These specifications are evolving.  If the ISO C9x standard is finalized with a  differ-
       ent conclusion, these specifications will change to conform to the ISO C9x standard decision.

       The conversion specification for %u was changed in the Solaris 8 release. This change was based on the XPG4 specification.

       If  using  the  %Z specifier and zoneinfo timezones and if the input date is outside the range 20:45:52 UTC, December  13, 1901 to 03:14:07
       UTC, January 19, 2038, the timezone name may not be correct.

SunOS 5.10                                                          1 Nov 2003                                                        strftime(3C)