STRPTIME(3P) POSIX Programmer's Manual STRPTIME(3P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
Linux manual page for details of Linux behavior), or the interface may
not be implemented on Linux.
NAMEstrptime — date and time conversion
SYNOPSIS
#include <time.h>
char *strptime(const char *restrict buf, const char *restrict format,
struct tm *restrict tm);
DESCRIPTION
The strptime() function shall convert the character string pointed to
by buf to values which are stored in the tm structure pointed to by tm,
using the format specified by format.
The format is composed of zero or more directives. Each directive is
composed of one of the following: one or more white-space characters
(as specified by isspace()); an ordinary character (neither '%' nor a
white-space character); or a conversion specification.
Each conversion specification is introduced by the '%' character after
which the following appear in sequence:
* An optional flag, the zero character ('0') or the <plus-sign> char‐
acter ('+'), which is ignored.
* An optional field width. If a field width is specified, it shall be
interpreted as a string of decimal digits that will determine the
maximum number of bytes converted for the conversion rather than
the number of bytes specified below in the description of the con‐
version specifiers.
* An optional E or O modifier.
* A terminating conversion specifier character that indicates the
type of conversion to be applied.
The conversions are determined using the LC_TIME category of the cur‐
rent locale. The application shall ensure that there is white-space or
other non-alphanumeric characters between any two conversion specifica‐
tions unless all of the adjacent conversion specifications convert a
known, fixed number of characters. In the following list, the maximum
number of characters scanned (excluding the one matching the next
directive) is as follows:
* If a maximum field width is specified, then that number
* Otherwise, the pattern "{x}" indicates that the maximum is x
* Otherwise, the pattern "[x,y]" indicates that the value shall fall
within the range given (both bounds being inclusive), and the maxi‐
mum number of characters scanned shall be the maximum required to
represent any value in the range without leading zeros and without
a leading <plus-sign>
The following conversion specifiers are supported.
The results are unspecified if a modifier is specified with a flag or
with a minimum field width, or if a field width is specified for any
conversion specifier other than C, F, or Y.
a The day of the week, using the locale's weekday names; either
the abbreviated or full name may be specified.
A Equivalent to %a.
b The month, using the locale's month names; either the abbrevi‐
ated or full name may be specified.
B Equivalent to %b.
c Replaced by the locale's appropriate date and time representa‐
tion.
C All but the last two digits of the year {2}; leading zeros
shall be permitted but shall not be required. A leading '+' or
'−' character shall be permitted before any leading zeros but
shall not be required.
d The day of the month [01,31]; leading zeros shall be permitted
but shall not be required.
D The date as %m/%d/%y.
e Equivalent to %d.
h Equivalent to %b.
H The hour (24-hour clock) [00,23]; leading zeros shall be per‐
mitted but shall not be required.
I The hour (12-hour clock) [01,12]; leading zeros shall be per‐
mitted but shall not be required.
j The day number of the year [001,366]; leading zeros shall be
permitted but shall not be required.
m The month number [01,12]; leading zeros shall be permitted but
shall not be required.
M The minute [00,59]; leading zeros shall be permitted but shall
not be required.
n Any white space.
p The locale's equivalent of a.m. or p.m.
r 12-hour clock time using the AM/PM notation if t_fmt_ampm is
not an empty string in the LC_TIME portion of the current
locale; in the POSIX locale, this shall be equivalent to
%I:%M:%S %p.
R The time as %H:%M.
S The seconds [00,60]; leading zeros shall be permitted but shall
not be required.
t Any white space.
T The time as %H:%M:%S.
U The week number of the year (Sunday as the first day of the
week) as a decimal number [00,53]; leading zeros shall be per‐
mitted but shall not be required.
w The weekday as a decimal number [0,6], with 0 representing Sun‐
day.
W The week number of the year (Monday as the first day of the
week) as a decimal number [00,53]; leading zeros shall be per‐
mitted but shall not be required.
x The date, using the locale's date format.
X The time, using the locale's time format.
y The last two digits of the year. When format contains neither a
C conversion specifier nor a Y conversion specifier, values in
the range [69,99] shall refer to years 1969 to 1999 inclusive
and values in the range [00,68] shall refer to years 2000 to
2068 inclusive; leading zeros shall be permitted but shall not
be required. A leading '+' or '−' character shall be permitted
before any leading zeros but shall not be required.
Note: It is expected that in a future version of this stan‐
dard the default century inferred from a 2-digit year
will change. (This would apply to all commands
accepting a 2-digit year as input.)
Y The full year {4}; leading zeros shall be permitted but shall
not be required. A leading '+' or '−' character shall be per‐
mitted before any leading zeros but shall not be required.
% Replaced by %.
Modified Conversion Specifiers
Some conversion specifiers 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 con‐
version specifier. If the alternative format or specification does not
exist in the current locale, the behavior shall be as if the unmodified
conversion specification were used.
%Ec The locale's alternative appropriate 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.
%Od The day of the month using the locale's alternative numeric
symbols; leading zeros shall be permitted but shall not be
required.
%Oe Equivalent to %Od.
%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 number of the weekday (Sunday=0) using the locale's alter‐
native 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.
A conversion specification composed of white-space characters is exe‐
cuted by scanning input up to the first character that is not white-
space (which remains unscanned), or until no more characters can be
scanned.
A conversion specification that is an ordinary character is executed by
scanning the next character from the buffer. If the character scanned
from the buffer differs from the one comprising the directive, the
directive fails, and the differing and subsequent characters remain
unscanned.
A series of conversion specifications composed of %n, %t, white-space
characters, or any combination is executed by scanning up to the first
character that is not white space (which remains unscanned), or until
no more characters can be scanned.
Any other conversion specification is executed by scanning characters
until a character matching the next directive is scanned, or until no
more characters can be scanned. These characters, except the one match‐
ing the next directive, are then compared to the locale values associ‐
ated with the conversion specifier. If a match is found, values for the
appropriate tm structure members are set to values corresponding to the
locale information. Case is ignored when matching items in buf such as
month or weekday names. If no match is found, strptime() fails and no
more characters are scanned.
RETURN VALUE
Upon successful completion, strptime() shall return a pointer to the
character following the last character parsed. Otherwise, a null
pointer shall be returned.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
Convert a Data-Plus-Time String to Broken-Down Time and Then into Seconds
The following example demonstrates the use of strptime() to convert a
string into broken-down time. The broken-down time is then converted
into seconds since the Epoch using mktime().
#include <time.h>
...
struct tm tm;
time_t t;
if (strptime("6 Dec 2001 12:33:45", "%d %b %Y %H:%M:%S", &tm) == NULL)
/* Handle error */;
printf("year: %d; month: %d; day: %d;\n",
tm.tm_year, tm.tm_mon, tm.tm_mday);
printf("hour: %d; minute: %d; second: %d\n",
tm.tm_hour, tm.tm_min, tm.tm_sec);
printf("week day: %d; year day: %d\n", tm.tm_wday, tm.tm_yday);
tm.tm_isdst = −1; /* Not set by strptime(); tells mktime()
to determine whether daylight saving time
is in effect */
t = mktime(&tm);
if (t == −1)
/* Handle error */;
printf("seconds since the Epoch: %ld\n", (long) t);"
APPLICATION USAGE
Several ``equivalent to'' formats and the special processing of white-
space characters are provided in order to ease the use of identical
format strings for strftime() and strptime().
It should be noted that dates constructed by the strftime() function
with the %Y or %C%y conversion specifiers may have values larger than
9999. If the strptime() function is used to read such values using %C%y
or %Y, the year values will be truncated to four digits. Applications
should use %+w%y or %+xY with w and x set large enough to contain the
full value of any years that will be printed or scanned.
See also the APPLICATION USAGE section in strftime().
It is unspecified whether multiple calls to strptime() using the same
tm structure will update the current contents of the structure or over‐
write all contents of the structure. Conforming applications should
make a single call to strptime() with a format and all data needed to
completely specify the date and time being converted.
RATIONALE
See the RATIONALE section for strftime().
FUTURE DIRECTIONS
None.
SEE ALSOfprintf(), fscanf(), strftime(), time()
The Base Definitions volume of POSIX.1‐2008, <time.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the source
files to man page format. To report such errors, see https://www.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 STRPTIME(3P)
