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a.TH curl_getdate 3 "12 Aug 2005" "libcurl" "libcurl"
NAME
curl_getdate - Convert a date string to number of seconds
SYNOPSIS
#include <curl/curl.h>
time_t curl_getdate(char *datestring, time_t *now);
DESCRIPTION
curl_getdate(3) returns the number of seconds since the Epoch, January
1st 1970 00:00:00 in the UTC time zone, for the date and time that the
datestring parameter specifies. The now parameter is not used, pass a
NULL there.
This function works with valid dates and does not always detect and
reject wrong dates, such as February 30.
PARSING DATES AND TIMES
A "date" is a string containing several items separated by whitespace.
The order of the items is immaterial. A date string may contain many
flavors of items:
calendar date items
Can be specified several ways. Month names can only be three-
letter English abbreviations, numbers can be zero-prefixed and
the year may use 2 or 4 digits. Examples: 06 Nov 1994,
06-Nov-94 and Nov-94 6.
time of the day items
This string specifies the time on a given day. You must specify
it with 6 digits with two colons: HH:MM:SS. To not include the
time in a date string, will make the function assume 00:00:00.
Example: 18:19:21.
time zone items
Specifies international time zone. There are a few acronyms
supported, but in general you should instead use the specific
relative time compared to UTC. Supported formats include:
-1200, MST, +0100.
day of the week items
Specifies a day of the week. Days of the week may be spelled
out in full (using English): `Sunday', `Monday', etc or they
may be abbreviated to their first three letters. This is
usually not info that adds anything.
pure numbers
If a decimal number of the form YYYYMMDD appears, then YYYY is
read as the year, MM as the month number and DD as the day of
the month, for the specified calendar date.
EXAMPLE
time_t t;
t = curl_getdate("Sun, 06 Nov 1994 08:49:37 GMT", NULL);
t = curl_getdate("Sunday, 06-Nov-94 08:49:37 GMT", NULL);
t = curl_getdate("Sun Nov 6 08:49:37 1994", NULL);
t = curl_getdate("06 Nov 1994 08:49:37 GMT", NULL);
t = curl_getdate("06-Nov-94 08:49:37 GMT", NULL);
t = curl_getdate("Nov 6 08:49:37 1994", NULL);
t = curl_getdate("06 Nov 1994 08:49:37", NULL);
t = curl_getdate("06-Nov-94 08:49:37", NULL);
t = curl_getdate("1994 Nov 6 08:49:37", NULL);
t = curl_getdate("GMT 08:49:37 06-Nov-94 Sunday", NULL);
t = curl_getdate("94 6 Nov 08:49:37", NULL);
t = curl_getdate("1994 Nov 6", NULL);
t = curl_getdate("06-Nov-94", NULL);
t = curl_getdate("Sun Nov 6 94", NULL);
t = curl_getdate("1994.Nov.6", NULL);
t = curl_getdate("Sun/Nov/6/94/GMT", NULL);
t = curl_getdate("Sun, 06 Nov 1994 08:49:37 CET", NULL);
t = curl_getdate("06 Nov 1994 08:49:37 EST", NULL);
t = curl_getdate("Sun, 12 Sep 2004 15:05:58 -0700", NULL);
t = curl_getdate("Sat, 11 Sep 2004 21:32:11 +0200", NULL);
t = curl_getdate("20040912 15:05:58 -0700", NULL);
t = curl_getdate("20040911 +0200", NULL);
STANDARDS
This parser handles date formats specified in RFC 822 (including the
update in RFC 1123) using time zone name or time zone delta and RFC 850
(obsoleted by RFC 1036) and ANSI C's asctime() format.
These formats are the only ones RFC 7231 says HTTP applications may
use.
AVAILABILITY
Always
RETURN VALUE
This function returns -1 when it fails to parse the date string.
Otherwise it returns the number of seconds as described.
On systems with a signed 32 bit time_t: if the year is larger than 2037
or less than 1903, this function will return -1.
On systems with an unsigned 32 bit time_t: if the year is larger than
2106 or less than 1970, this function will return -1.
On systems with 64 bit time_t: if the year is less than 1583, this
function will return -1. (The Gregorian calendar was first introduced
1582 so no "real" dates in this way of doing dates existed before
then.)
SEE ALSO
curl_easy_escape(3), curl_easy_unescape(3), CURLOPT_TIMECONDITION(3),
CURLOPT_TIMEVALUE(3)
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