STRPTIME(3)

NAME
strptime - converts a character string to a time value

LIBRARY
libc

SYNOPSIS
#include <time.h>
char *
strptime(const char * restrict buf, const char * restrict format, struct tm * restrict timeptr);
char *
strptime_l(const char * restrict buf, const char * restrict format, struct tm * restrict timeptr, locale_t loc);

DESCRIPTION
The strptime() function converts the character string pointed to by buf according to the string pointed to by format, and fills in the elements of the structure pointed to by timeptr. The resulting values will be relative to the local time zone. Thus, it can be considered the reverse operation of strftime(3). The strptime_l() function does the same as strptime(), but takes an explicit locale in the locale_t loc argument rather than using the current locale.

The format string consists of zero or more conversion specifications and ordinary characters. All ordinary characters in are compared directly against the corresponding characters in buf; comparisons which fail will cause strptime() to fail. Whitespace characters in format match any number of whitespace characters in buf, including none. All conversion specifications are identical to those described in strftime(3).

Two-digit year values, including formats %y and %D, are now interpreted as beginning at 1969 per POSIX requirements. Years 69-00 are interpreted in the 20th century (1969-2000), years 01-68 in the 21st century (2001-2068). The %U and %W format specifiers accept any value within the range 00 to 53.

If the format string does not contain enough conversion specifications to completely specify the resulting struct tm, the unspecified members of timeptr are left untouched. For example, if format is “%H:%M:%S”, only tm_hour, tm_sec tm_min will be modified. If time relative to today is desired, initialize the timeptr structure with today's date before passing it to strptime(). All ordinary characters in are compared directly against the corresponding characters in buf; comparisons which fail will cause strptime() to fail. Whitespace characters in format match any number of whitespace characters in buf, including none.

A conversion specification consists of a percent sign ‘%’ followed by one or two conversion characters which specify the replacement required. There must be white-space or other non-alphanumeric characters between any two conversion specifications.

Conversion of alphanumeric strings (such as month and weekday names) is done without regard to case. Conversion specifications which cannot be matched will cause strptime() to fail.

The LC_TIME category defines the locale values for the conversion specifications. The following conversion specifications are supported:

%a  the day of week, using the locale's weekday names; either the abbreviated or full name may be specified.

%A  the same as %a.

%b  the month, using the locale's month names; either the abbreviated or full name may be specified.

%B  the same as %b.

%c  the date and time, using the locale's date and time format.

%C  the century number [0,99]; leading zeros are permitted but not required. This conversion should be used in conjunction with the %y conversion.

%d  the day of month [1,31]; leading zeros are permitted but not required.

%D  the date as %m/%d/%y.

%e  the same as %d.

%F  the date as %Y-%m-%d (the ISO 8601 date format).

%g  the year corresponding to the ISO week number, without the century. ( A NetBSD extension.)

%G  the year corresponding to the ISO week number, with the century. ( A NetBSD extension.)

%h  the same as %b.

%H  the hour (24-hour clock) [0,23]; leading zeros are permitted but not required.

%I  the hour (12-hour clock) [1,12]; leading zeros are permitted but not required.

%j  the day number of the year [1,366]; leading zeros are permitted but not required.

%k  the same as %H.

%l  the same as %I.

%m  the month number [1,12]; leading zeros are permitted but not required.

%M  the minute [0,59]; leading zeros are permitted but not required.

%n  any white-space, including none.

%p  the locale's equivalent of a.m. or p.m.

%r  the time (12-hour clock) with %p, using the locale's time format.

%R  the time as %H:%M.

%S  the seconds [0,60]; leading zeros are permitted but not required.

%s  the number of seconds since the Epoch, UTC (see mktime(3)). ( A NetBSD extension.)

%t  any white-space, including none.

%T  the time as %H:%M:%S.

%u  the day of the week as a decimal number, where Monday = 1. ( A NetBSD extension.)

%U  the week number of the year (Sunday as the first day of the week) as a decimal number [0,53]; leading zeros are permitted but not required. All days in a year preceding the first Sunday are considered to be in week 0.

%V  the ISO 8601:1988 week number as a decimal number. If the week (starting on Monday) that contains January 1 has more than three days in the new year, then it is considered the first week of the year. If it has fewer than four days in the new year, then it is considered the last week of the previous year. Weeks are numbered from 1 to 53. ( A NetBSD extension.)

%w  the weekday as a decimal number [0,6], with 0 representing Sunday; leading zeros are permitted but not required.

%W  the week number of the year (Monday as the first day of the week) as a decimal number [0,53]; leading zeros are permitted but not required. All days in a year preceding the first Monday are considered to be in week 0.

%x  the date, using the locale's date format.

%X  the time, using the locale's time format.

%y  the year within the 20th century [69,99] or the 21st century [0,68]; leading zeros are permitted but not required. If specified in conjunction with %C, specifies the year [0,99] within that century.

%Y  the year, including the century (i.e., 1996).

%z  an ISO 8601, RFC-2822, or RFC-3339 time zone specification. ( A NetBSD extension.) This is one of the following:
    -   The offset from Coordinated Universal Time (‘UTC’) specified as:
        •   [+-]hhmm
        •   [+-]hh:mm
        •   [+-]hh
    -   ‘UTC’ specified as:
        •   UTC (‘Coordinated Universal Time’)
        •   GMT (‘Greenwich Mean Time’)
        •   UT (‘Universal Time’)
        •   Z (‘Zulu Time’)
    -   A three character US time zone specified as:
        •   EDT
        •   EST
        •   CDT
        •   CST
        •   MDT
        •   MST
        •   PDT
        •   PST
        with the first letter standing for ‘Eastern’ (“E”), ‘Central’ (“C”), ‘Mountain’ (“M”) or ‘Pacific’ (“P”), and the second letter standing for ‘Daylight’ ( “D” or summer) time or ‘Standard’ (“S”) time
    -   a single letter military or nautical time zone specified as:
        •   “A” through “I”
        •   “K” through “Y”
        •   “J” (non-nautical local time zone)
    -   An arbitrary timezone name that can be loaded from the database.

%Z  time zone name or no characters when time zone information is unavailable. ( A NetBSD extension.)

%%  matches a literal `%'. No argument is converted.

  Modified conversion specifications
For compatibility, certain conversion specifications can be modified by the E and O modifier characters to indicate that an alternative format or specification should be used rather than the one normally used by the unmodified conversion specification. As there are currently neither alternative formats nor specifications supported by the system, the behavior will be as if the unmodified conversion specification were used.

Case is ignored when matching string items in buf, such as month and weekday names.

RETURN VALUES
If successful, the strptime() function returns a pointer to the character following the last character parsed. Otherwise, a NULL pointer is returned.

SEE ALSO
ctime(3), isspace(3), localtime(3), strftime(3), tm(3)

STANDARDS
The strptime() function conforms to xpg4.

BUGS
The %Z format specifier only accepts time zone abbreviations of the local time zone, or the values “GMT” or “UTC”. This limitation is caused by the ambiguity of overloaded time zone abbreviations, for example EST is both Eastern Standard Time and Eastern Australia Summer Time.