STRFTIME(3)

NAME
strftime - format date and time

SYNOPSIS
#include <time.h>

size_t strftime(char *s, size_t max, const char *format,
				const struct tm *tm);

DESCRIPTION
The strftime() function formats the broken-down time tm according to the format specification format and places the result in the character array s of size max.

Ordinary characters placed in the format string are copied to s without conversion. Conversion specifiers are introduced by a `%' character, and are replaced in s as follows:

%a  The abbreviated weekday name according to the current locale.

%A  The full weekday name according to the current locale.

%b  The abbreviated month name according to the current locale.

%B  The full month name according to the current locale.

%c  The preferred date and time representation for the current locale.

%d  The day of the month as a decimal number (range 01 to 31).

%H  The hour as a decimal number using a 24-hour clock (range 00 to 23).

%I  The hour as a decimal number using a 12-hour clock (range 01 to 12).

%j  The day of the year as a decimal number (range 001 to 366).

%m  The month as a decimal number (range 01 to 12).

%M  The minute as a decimal number.

%p  Either `am' or `pm' according to the given time value, or the corresponding strings for the current locale.

%S  The second as a decimal number.

%U  The week number of the current year as a decimal number, starting with the first Sunday as the first day of the first week.

%W  The week number of the current year as a decimal number, starting with the first Monday as the first day of the first week.

%w  The day of the week as a decimal, Sunday being 0.

%x  The preferred date representation for the current locale without the time.

%X  The preferred time representation for the current locale without the date.

%y  The year as a decimal number without a century (range 00 to 99).

%Y  The year as a decimal number including the century.

%Z  The time zone or name or abbreviation.

%%  A literal `%' character.

The broken-down time structure tm is defined in <time.h> as follows:

    struct tm
    {
    	int	tm_sec;			/* seconds */
    	int	tm_min;			/* minutes */
    	int	tm_hour;		/* hours */
    	int	tm_mday;		/* day of the month */
    	int	tm_mon;			/* month */
    	int	tm_year;		/* year */
    	int	tm_wday;		/* day of the week */
    	int	tm_yday;		/* day in the year */
    	int	tm_isdst;		/* daylight saving time */
    };

The members of the tm structure are:

tm_sec
    The number of seconds after the minute, normally in the range 0 to 59, but can be up to 61 to allow for leap seconds.

tm_min
    The number of minutes after the hour, in the range 0 to 59.

tm_hour
    The number of hours past midnight, in the range 0 to 23.

tm_mday
    The day of the month, in the range 1 to 31.

tm_mon
    The number of months since January, in the range 0 to 11.

tm_year
    The number of years since 1900.

tm_wday
    The number of days since Sunday, in the range 0 to 6.

tm_yday
    The number of days since January 1, in the range 0 to 365.

tm_isdst
    A flag that indicates whether daylight saving time is in effect at the time described. The value is positive if daylight saving time is in effect, zero if it is not, and negative if the information is not available.

RETURN VALUE
The strftime() function returns the number of characters placed in the array s, not including the terminating NULL character, provided the string, including the terminating NULL, fits. Otherwise, it returns 0, and the contents of the array is undefined. (Thus at least since libc 4.4.4; very old versions of libc, such as libc 4.4.1, would return max if the array was too small.)

CONFORMING TO
ANSI C, SVID 3, POSIX, BSD 4.3, ISO 9899

SEE ALSO
date(1), time(2), ctime(3), setlocale(3), sprintf(3)

NOTES
The function supports only those locales specified in locale(7)