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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | STANDARDS | HISTORY | NOTES | EXAMPLES | SEE ALSO | COLOPHON |
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strptime(3) Library Functions Manual strptime(3)
strptime - convert a string representation of time to a time tm
structure
Standard C library (libc, -lc)
#define _XOPEN_SOURCE /* See feature_test_macros(7) */
#include <time.h>
char *strptime(const char *restrict s, const char *restrict format,
struct tm *restrict tm);
The strptime() function is the converse of strftime(3); it
converts the character string pointed to by s to values which are
stored in the "broken-down time" structure pointed to by tm, using
the format specified by format.
The broken-down time structure tm is described in tm(3type).
The format argument 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, except for whitespace, which
matches zero or more whitespace characters in the input string.
There should be whitespace or other alphanumeric characters
between any two field descriptors.
The strptime() function processes the input string from left to
right. Each of the three possible input elements (whitespace,
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 supported input field descriptors are listed below. In case a
text string (such as the name of a day of the week or a month
name) is to be matched, the comparison is case insensitive. In
case a number is to be matched, leading zeros are permitted but
not required.
%% The % character.
%a or %A
The name of the day of the week according to the current
locale, in abbreviated form or the full name.
%b or %B or %h
The month name according to the current locale, in
abbreviated form or the full name.
%c The date and time representation for the current locale.
%C The century number (0–99).
%d or %e
The day of month (1–31).
%D Equivalent to %m/%d/%y. (This is the American style date,
very confusing to non-Americans, especially since %d/%m/%y
is widely used in Europe. The ISO 8601 standard format is
%Y-%m-%d.)
%H The hour (0–23).
%I The hour on a 12-hour clock (1–12).
%j The day number in the year (1–366).
%m The month number (1–12).
%M The minute (0–59).
%n Arbitrary whitespace.
%p The locale's equivalent of AM or PM. (Note: there may be
none.)
%r The 12-hour clock time (using the locale's AM or PM). In
the POSIX locale equivalent to %I:%M:%S %p. If t_fmt_ampm
is empty in the LC_TIME part of the current locale, then
the behavior is undefined.
%R Equivalent to %H:%M.
%S The second (0–60; 60 may occur for leap seconds; earlier
also 61 was allowed).
%t Arbitrary whitespace.
%T Equivalent to %H:%M:%S.
%U The week number with Sunday the first day of the week
(0–53). The first Sunday of January is the first day of
week 1.
%w The ordinal number of the day of the week (0–6), with
Sunday = 0.
%W The week number with Monday the first day of the week
(0–53). The first Monday of January is the first day of
week 1.
%x The date, using the locale's date format.
%X The time, using the locale's time format.
%y The year within century (0–99). When a century is not
otherwise specified, values in the range 69–99 refer to
years in the twentieth century (1969–1999); values in the
range 00–68 refer to years in the twenty-first century
(2000–2068).
%Y The year, including century (for example, 1991).
Some field descriptors can be modified by the E or O modifier
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 descriptor
is used.
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 representation.
%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 alternative
numeric symbols.
%OI The hour (12-hour clock) using the locale's alternative
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 ordinal number of the day of the week (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 alternative
numeric symbols.
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 null 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.
For an explanation of the terms used in this section, see
attributes(7).
┌───────────────────────────┬───────────────┬────────────────────┐
│ Interface │ Attribute │ Value │
├───────────────────────────┼───────────────┼────────────────────┤
│ strptime() │ Thread safety │ MT-Safe env locale │
└───────────────────────────┴───────────────┴────────────────────┘
POSIX.1-2008.
POSIX.1-2001, SUSv2.
In principle, this function does not initialize tm but stores only
the values specified. This means that tm should be initialized
before the call. Details differ a bit between different UNIX
systems. The glibc implementation 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.
The 'y' (year in century) specification is taken to specify a year
in the range 1950–2049 by glibc 2.0. It is taken to be a year in
1969–2068 since glibc 2.1.
glibc notes
For reasons of symmetry, glibc tries to support for strptime() the
same format characters as for strftime(3). (In most cases, the
corresponding fields are parsed, but no field in tm is changed.)
This leads to
%F Equivalent to %Y-%m-%d, the ISO 8601 date format.
%g The year corresponding to the ISO week number, but without
the century (0–99).
%G The year corresponding to the ISO week number. (For
example, 1991.)
%u The day of the week as a decimal number (1–7, where Monday
= 1).
%V The ISO 8601:1988 week number as a decimal number (1–53).
If the week (starting on Monday) containing 1 January has
four or more days in the new year, then it is considered
week 1. Otherwise, it is the last week of the previous
year, and the next week is week 1.
%z An RFC-822/ISO 8601 standard timezone specification.
%Z The timezone name.
Similarly, because of GNU extensions to strftime(3), %k is
accepted as a synonym for %H, and %l should be accepted as a
synonym for %I, and %P is accepted as a synonym for %p. Finally
%s The number of seconds since the Epoch, 1970-01-01 00:00:00
+0000 (UTC). Leap seconds are not counted unless leap
second support is available.
The glibc implementation does not require whitespace between two
field descriptors.
The following example demonstrates the use of strptime() and
strftime(3).
#define _XOPEN_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
int
main(void)
{
struct tm tm;
char buf[255];
memset(&tm, 0, sizeof(tm));
strptime("2001-11-12 18:31:01", "%Y-%m-%d %H:%M:%S", &tm);
strftime(buf, sizeof(buf), "%d %b %Y %H:%M", &tm);
puts(buf);
exit(EXIT_SUCCESS);
}
time(2), getdate(3), scanf(3), setlocale(3), strftime(3)
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Linux man-pages 6.15 2025-05-17 strptime(3)
Pages that refer to this page: dpkg-parsechangelog(1), ctime(3), getdate(3), strftime(3), tm(3type), locale(5), locale(7), time(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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