illumos: manual page: strptime.3c

STRPTIME(3C) Standard C Library Functions STRPTIME(3C)

NAME

strptime, strptime_l - date and time conversion

SYNOPSIS

#include <time.h>

char *strptime(const char *restrict buf,
const char *restrict format, struct tm *restrict tm);

#include <time.h>
#include <xlocale.h>

char *strptime_l(const char *restrict buf,
const char *restrict format, struct tm *restrict tm,
locale_t loc);

Non-zeroing Behavior
cc [flag...] file... -D_STRPTIME_DONTZERO [library...]
#include <time.h>

char *strptime(const char *restrict buf,
const char *restrict format, struct tm *restrict tm);

DESCRIPTION

The strptime() function converts 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 strptime_l() function is identical to
strptime() except instead of acting in the current locale, it acts in the
locale specified by the argument loc.

The format argument is composed of zero or more conversion
specifications. Each conversion specification is composed of a "%"
(percent) character followed by one or two conversion characters which
specify the replacement required. One or more white space characters (as
specified by isspace(3C)) may precede or follow a conversion
specification. There must be white-space or other non-alphanumeric
characters between any two conversion specifications.

A non-zeroing version of strptime(), described below under Non-zeroing
Behavior, is provided if _STRPTIME_DONTZERO is defined.

Conversion Specifications

The following conversion specifications are supported:

%%
Same as %.

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

%A
Same as %a.

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

%B
Same as %b.

%c
Locale's appropriate date and time representation.

%C
Century number (the year divided by 100 and truncated to an integer
as a decimal number [1,99]); single digits are preceded by 0. If %C
is used without the %y specifier, strptime() assumes the year
offset is zero in whichever century is specified. Note the
behavior of %C in the absence of %y is not specified by any of the
standards or specifications described on the standards(7) manual
page, so portable applications should not depend on it. This
behavior may change in a future release.

%d
Day of month [1,31]; leading zero is permitted but not required.

%D
Date as %m/%d/%y.

%e
Same as %d.

%h
Same as %b.

%H
Hour (24-hour clock) [0,23]; leading zero is permitted but not
required.

%I
Hour (12-hour clock) [1,12]; leading zero is permitted but not
required.

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

%m
Month number [1,12]; leading zero is permitted but not required.

%M
Minute [0-59]; leading zero is permitted but not required.

%n
Any white space.

%p
Locale's equivalent of either a.m. or p.m.

%r
Appropriate time representation in the 12-hour clock format with
%p.

%R
Time as %H:%M.

SUSv3
%S
Seconds [0,60]; leading zero is permitted but not required. The
range of values is [00,60] rather than [00,59] to allow for the
occasional leap second.

Default and other standards

%S
Seconds [0,61]; leading zero is permitted but not required. The
range of values is [00,61] rather than [00,59] to allow for the
occasional leap second and even more occasional double leap second.

%t
Any white space.

%T
Time as %H:%M:%S.

%U
Week number of the year as a decimal number [0,53], with Sunday as
the first day of the week; leading zero is permitted but not
required.

%w
Weekday as a decimal number [0,6], with 0 representing Sunday.

%W
Week number of the year as a decimal number [0,53], with Monday as
the first day of the week; leading zero is permitted but not
required.

%x
Locale's appropriate date representation.

%X
Locale's appropriate time representation.

%y
Year within century. 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 the century (for example, 1993).

%Z
Time zone name or no characters if no time zone exists.

Modified Conversion Specifications

Some conversion specifications can be modified by the E and O modifier
characters to indicate that an alternate format or specification should
be used rather than the one normally used by the unmodified
specification. If the alternate format or specification does not exist in
the current locale, the behavior will be as if the unmodified conversion
specification were used.

%Ec
Locale's alternate appropriate date and time representation.

%EC
Name of the base year (era) in the locale's alternate
representation.

%Ex
Locale's alternate date representation.

%EX
Locale's alternate time representation.

%Ey
Offset from %EC (year only) in the locale's alternate
representation.

%EY
Full alternate year representation.

%Od
Day of the month using the locale's alternate numeric symbols.

%Oe
Same as %Od.

%OH
Hour (24-hour clock) using the locale's alternate numeric symbols.

%OI
Hour (12-hour clock) using the locale's alternate numeric symbols.

%Om
Month using the locale's alternate numeric symbols.

%OM
Minutes using the locale's alternate numeric symbols.

%OS
Seconds using the locale's alternate numeric symbols.

%OU
Week number of the year (Sunday as the first day of the week)
using the locale's alternate numeric symbols.

%Ow
Number of the weekday (Sunday=0) using the locale's alternate
numeric symbols.

%OW
Week number of the year (Monday as the first day of the week)
using the locale's alternate numeric symbols.

%Oy
Year (offset from %C) in the locale's alternate representation
and using the locale's alternate numeric symbols.

General Specifications

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 specification, the
specification fails, and the differing and subsequent characters remain
unscanned.

A series of 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. White space is defined by isspace(3C).

Any other conversion specification is executed by scanning characters
until a character matching the next specification is scanned, or until no
more characters can be scanned. These characters, except the one matching
the next specification, 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. If no match is found, strptime() fails and no more
characters are scanned.

The month names, weekday names, era names, and alternate numeric symbols
can consist of any combination of upper and lower case letters. The user
can request that the input date or time specification be in a specific
language by setting the LC_TIME category using setlocale(3C).

Non-zeroing Behavior
In addition to the behavior described above by various standards, the
Solaris implementation of strptime() provides the following extensions.
These may change at any time in the future. Portable applications should
not depend on these extended features:

o If _STRPTIME_DONTZERO is not defined, the tm struct is zeroed
on entry and strptime() updates the fields of the tm struct
associated with the specifiers in the format string.

o If _STRPTIME_DONTZERO is defined, strptime() does not zero the
tm struct on entry. Additionally, for some specifiers,
strptime() will use some values in the input tm struct to
recalculate the date and re-assign the appropriate members of
the tm struct.

The following describes extended features regardless of whether
_STRPTIME_DONTZERO is defined or not defined:

o If %j is specified, tm_yday is set; if year is given, and if
month and day are not given, strptime() calculates and sets
tm_mon, tm_mday, and tm_year.

o If %U or %W is specified and if weekday and year are given and
month and day of month are not given, strptime() calculates
and sets tm_mon, tm_mday, tm_wday, and tm_year.

The following describes extended features when _STRPTIME_DONTZERO is not
defined:

o If %C is specified and %y is not specified, strptime()assumes
0 as the year offset, then calculates the year, and assigns
tm_year.

The following describes extended features when _STRPTIME_DONTZERO is
defined:

o If %C is specified and %y is not specified, strptime() assumes
the year offset of the year value of the tm_year member of the
input tm struct, then calculates the year and assigns tm_year.

o If %j is specified and neither %y, %Y, nor %C are specified,
and neither month nor day of month are specified, strptime()
assumes the year value given by the value of the tm_year field
of the input tm struct. Then, in addition to setting tm_yday,
strptime() uses day-of-year and year values to calculate the
month and day-of-month, and assigns tm_month and tm_mday.

o If %U or %W is specified, and if weekday and/or year are not
given, and month and day of month are not given, strptime()
will assume the weekday value and/or the year value as the
value of the tm_wday field and/or tm_year field of the input
tm struct. Then, strptime() will calculate the month and day-
of-month and assign tm_month, tm_mday, and/or tm_year.

o If %p is specified and if hour is not specified, strptime()
will reference, and if needed, update the tm_hour member. If
the am_pm input is p.m. and the input tm_hour value is between
0 - 11, strptime() will add 12 hours and update tm_hour. If
the am_pm input is a.m. and input tm_hour value is between 12
- 23, strptime() will subtract 12 hours and update tm_hour.

RETURN VALUES

Upon successful completion, strptime() returns a pointer to the character
following the last character parsed. Otherwise, a null pointer is
returned.

USAGE

Several "same as" formats, and the special processing of white-space
characters are provided in order to ease the use of identical format
strings for strftime(3C) and strptime().

The strptime() function tries to calculate tm_year, tm_mon, and tm_mday
when given incomplete input. This allows the struct tm created by
strptime() to be passed to mktime(3C) to produce a time_t value for dates
and times that are representable by a time_t. As an example, since
mktime() ignores tm_yday, strptime() calculates tm_mon and tm_mday as
well as filling in tm_yday when %j is specified without otherwise
specifying a month and day within month.

ATTRIBUTES