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PARSEDATE(3)
NAME
  parsedate - convert time and date string to number

SYNOPSIS
  #include <sys/types.h>

  typedef struct _TIMEINFO {
      time_t	       time;
      long	       usec;
      long	       tzone;
  } TIMEINFO;

  time_t
  parsedate(text, now)
      char	       *text;
      TIMEINFO	       *now;

DESCRIPTION
  Parsedate converts many common time specifications into the number of
  seconds since the epoch - i.e., a time_t; see time(2).

  Parsedate returns the time, or -1 on error.  Text is a character string
  containing the time and date.	 Now is a pointer to the time that should be
  used for calculating relative dates.	If now is NULL, then GetTimeInfo in
  libinn(3) is used to obtain the current time and timezone.

  The character string consists of zero or more specifications of the
  following form:

  time A time of day, which is of the form hh[:mm[:ss]] [meridian] [zone] or
       hhmm [meridian] [zone].	If no meridian is specified, hh is
       interpreted on a 24-hour clock.

  date A specific month and day with optional year.  The acceptable formats
       are mm/dd[/yy], yyyy/mm/dd, monthname dd[, yy], dd monthname [yy], and
       day, dd monthname yy.  The default year is the current year.  If the
       year is less then 100, then 1900 is added to it; if it is less then
       21, then 2000 is added to it.

  relative time
       A specification relative to the current time.  The format is number
       unit; acceptable units are year, month, week, day, hour, minute (or
       min), and second (or sec).  The unit can be specified as a singular or
       plural, as in 3 weeks.

  The actual date is calculated according to the following steps.  First, any
  absolute date and/or time is processed and converted.	 Using that time as
  the base, day-of-week specifications are added.  Next, relative
  specifications are used.  If a date or day is specified, and no absolute or
  relative time is given, midnight is used.  Finally, a correction is applied
  so that the correct hour of the day is produced after allowing for daylight
  savings time differences.

  Parsedate ignores case when parsing all words; unknown words are taken to
  be unknown timezones, which are treated as GMT.  The names of the months
  and days of the week can be abbreviated to their first three letters, with
  optional trailing period.  Periods are ignored in any timezone or meridian
  values.

BUGS
  Parsedate does not accept all desirable and unambiguous constructions.
  Semantically incorrect dates such as ``February 31'' are accepted.

  Daylight savings time is always taken as a one-hour change which is wrong
  for some places.  The daylight savings time correction can get confused if
  parsing a time within an hour of when the reckoning changes, or if given a
  partial date.

HISTORY
  Originally written by Steven M. Bellovin <smb@research.att.com> while at
  the University of North Carolina at Chapel Hill and distributed under the
  name getdate.

  A major overhaul was done by Rich $alz <rsalz@bbn.com> and Jim Berets
  <jberets@bbn.com> in August, 1990.

  It was further revised (primarily to remove obsolete constructs and
  timezone names) a year later by Rich (now <rsalz@osf.org>) for
  InterNetNews, and the name was changed.  This is revision 6312, dated
  2003-05-04.

SEE ALSO
  date(1), ctime(3), libinn(3), time(2).

Index for Section 3

Alphabetical listing for P

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