STRPTIME(3) Linux Programmer's Manual STRPTIME(3)
NAME
strptime - convert a string representation of time to a
time tm structure
SYNOPSIS
#define _XOPEN_SOURCE /* glibc2 needs this */
#include <time.h>
char *strptime(const char *s, const char *format, struct
tm *tm);
DESCRIPTION
strptime() is the complementary function to strftime() and
converts the character string pointed to by s to values
which are stored in the tm structure pointed to by tm,
using the format specified by format. Here format is a
character string that consists of field descriptors and
text characters, reminiscent of scanf(3). Each field
descriptor consists of a % character followed by another
character that specifies the replacement for the field
descriptor. All other characters in the format string
must have a matching character in the input string.
Exceptions are white spaces in the format string which can
match zero or more white space characters in the input
string.
The strptime() function processes the input string from
right to left. Each of the three possible input elements
(white space, literal, or format) are handled one after
the other. If the input cannot be matched to the format
string the function stops. The remainder of the format
and input strings are not processed.
The following field descriptors are supported:
%% the % character
%a or %A
day of week, using locale's weekday names; either
the abbreviated or full name may be specified
%b or %B or %h
month, using locale's month names; either the
abbreviated or full name may be specified
%c date and time as %x %X
%C date and time, in locale's long-format date and
time representation
%d or %e
day of month (1-31; leading zeroes are permitted
but not required)
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%D date as %m/%d/%y
%H or %k
hour (0-23; leading zeroes are permitted but not
required)
%I or %l
hour (0-12; leading zeroes are permitted but not
required)
%j day number of year (001-366)
%m month number (1-12; leading zeroes are permitted
but not required)
%M minute (0-59; leading zeroes are permitted but not
required)
%p locale's equivalent of AM or PM
%r time as %I:%M:%S %p
%R time as %H:%M
%S seconds (0-61; leading zeroes are permitted but not
required. Extra second allowed for leap years)
%T time as %H:%M:%S
%w weekday number (0-6) with Sunday as the first day
of the week
%x date, using locale's date format
%X time, using locale's time format
%y year within century (0-99; leading zeroes are per-
mitted but not required. When a century is not
otherwise specified, values in the range 69-99
refer to years in the twentieth century (1969 to
1999 inclusive); values in the range 00-68 refer to
years in the twenty-first century (2000 to 2068
inclusive).
%Y year, including century (for example, 1988)
Case is ignored when matching items such as month or week-
day names.
Some field descriptors can be modified by the E and O mod-
ifier characters to indicate that an alternative format or
specification should be used. If the alternative format or
specification does not exist in the current locale, the
unmodified field descriptors is used.
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The E modifier specifies that the input string may contain
alternative locale-dependent versions of the date and time
representation:
%Ec the locale's alternative date and time representa-
tion.
%EC the name of the base year (period) in the locale's
alternative representation.
%Ex the locale's alternative date representation.
%EX the locale's alternative time representation.
%Ey the offset from %EC (year only) in the locale's
alternative representation.
%EY the full alternative year representation.
The O modifier specifies that the numerical input may be
in an alternative locale-dependent format:
%Od or %Oe
the day of the month using the locale's alternative
numeric symbols; leading zeros are permitted but
not required.
%OH the hour (24-hour clock) using the locale's alter-
native numeric symbols.
%OI the hour (12-hour clock) using the locale's alter-
native numeric symbols.
%Om the month using the locale's alternative numeric
symbols.
%OM the minutes using the locale's alternative numeric
symbols.
%OS the seconds using the locale's alternative numeric
symbols.
%OU the week number of the year (Sunday as the first
day of the week) using the locale's alternative
numeric symbols.
%Ow the number of the weekday (Sunday=0) using the
locale's alternative numeric symbols.
%OW the week number of the year (Monday as the first
day of the week) using the locale's alternative
numeric symbols.
%Oy the year (offset from %C) using the locale's
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alternative numeric symbols.
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 */
};
RETURN VALUE
The return value of the function is a pointer to the first
character not processed in this function call. In case
the input string contains more characters than required by
the format string the return value points right after the
last consumed input character. In case the whole input
string is consumed the return value points to the NUL byte
at the end of the string. If strptime() fails to match
all of the format string and therefore an error occurred
the function returns NULL.
NOTES
In principle, this function does not initialize tm but
only stores the values specified. This means that tm
should be initialized before the call. Details differ a
bit between different Unix systems. The GNU libc imple-
mentation does not touch those fields which are not
explicitly specified, except that it recomputes the
tm_wday and tm_yday field if any of the year, month, or
day elements changed.
This function is available since libc 4.6.8. Linux libc4
and libc5 includes define the prototype unconditionally;
glibc2 includes provide a prototype only when
_XOPEN_SOURCE or _GNU_SOURCE are defined. The E and O
locale modifier characters are accepted since libc 5.4.13.
The 'y' (year in century) specification is taken to spec-
ify a year in the 20th century by libc4 and libc5. It is
taken to be a year in the range 1950-2049 by glibc 2.0. It
is taken to be a year in 1969-2068 by glibc 2.1.
SEE ALSO
time(2), scanf(3), setlocale(3), strftime(3)
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