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STRPTIME(3P) POSIX Programmer's Manual STRPTIME(3P)
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.
strptime — date and time conversion
#include <time.h>
char *strptime(const char *restrict buf, const char *restrict format,
struct tm *restrict tm);
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>
character ('+'), 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 conversion 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
current locale. The application shall ensure that there is white-
space or other non-alphanumeric characters between any two conversion
specifications 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 maximum 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
abbreviated or full name may be specified.
B Equivalent to %b.
c Replaced by the locale's appropriate date and time
representation.
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
permitted but shall not be required.
I The hour (12-hour clock) [01,12]; leading zeros shall be
permitted 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
permitted but shall not be required.
w The weekday as a decimal number [0,6], with 0 representing
Sunday.
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
permitted 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
standard 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
permitted 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
conversion 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
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.
%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
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.
A conversion specification composed of white-space characters is
executed 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
matching the next directive, are then compared to the locale values
associated 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.
Upon successful completion, strptime() shall return a pointer to the
character following the last character parsed. Otherwise, a null
pointer shall be returned.
No errors are defined.
The following sections are informative.
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);"
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(3p).
It is unspecified whether multiple calls to strptime() using the same
tm structure will update the current contents of the structure or
overwrite 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.
See the RATIONALE section for strftime(3p).
None.
fprintf(3p), fscanf(3p), strftime(3p), time(3p)
The Base Definitions volume of POSIX.1‐2008, time.h(0p)
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 Electrical 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.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 STRPTIME(3P)
Pages that refer to this page: time.h(0p), asctime(3p), clock(3p), ctime(3p), difftime(3p), gmtime(3p), localtime(3p), mktime(3p), strftime(3p), time(3p)