Index for Section 2

Alphabetical listing for G

gettimeofday(2)
NAME
  gettimeofday, settimeofday, ftime - Gets and sets date and time

SYNOPSIS
  #include <sys/time.h>


  int gettimeofday(
	  struct timeval *tp,
	  void *tzp );

  #include <sys/timeb.h>


  int ftime(
	  struct timeb *tp );

  The following function declarations do not conform to current standards and
  are supported only for backward compatibility:

  #include <sys/time.h>


  int gettimeofday(
	  struct timeval *tp,
	  struct timezone *tzp );

  int *settimeofday(
	  struct timeval *tp,
	  struct timezone *tzp );

LIBRARY
  Standard C Library (libc)

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  gettimeofday(), ftime():  XPG4-UNIX

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.








PARAMETERS
  tp  For gettimeofday() and settimeofday(), points to a timeval structure,
      defined in the <sys/time.h> file.

      For ftime(), points to a timeb structure, defined in the <sys/timeb.h>
      file.

  tzp [Compaq]	For the backward-compatible versions of gettimeofday() and
      settimeofday(), points to a timezone structure, defined in the
      <sys/time.h> file.

DESCRIPTION
  The gettimeofday(), ftime(), and settimeofday() functions get and set the
  time and timezone information stored in the kernel.

  The gettimeofday() function gets the current time, expressed in seconds and
  microseconds since midnight (0 hour), January 1, 1970 UTC (Coordinated
  Universal Time, formerly Greenwich Mean Time or GMT), and stores it in the
  timeval structure pointed to by tp.

  The ftime() function sets the time and millitm members of the timeb
  structure pointed to by tp to contain the seconds and milliseconds
  portions, respectively, of the current time in seconds since midnight (0
  hour), January 1, 1970 UTC.

  See the NOTES section for information on the backward-compatible versions
  of gettimeofday() and settimeofday().

  See the timezone(3) reference page for information on timezone handling on
  Tru64 UNIX systems.

NOTES
  The following information applies only to the backward-compatible versions
  of the gettimeofday() and settimeofday() functions.

  [Compaq]  The timezone structure that is returned for the gettimeofday()
  call is set at boot time by the /sbin/init.d/settime script. The
  tz_minuteswest field of the structure is set to your local time zone.	 This
  field is set only for backward compatibility with older applications that
  may use the gettimeofday() call for timezone information.  The tz_dsttime
  field is set to zero because this field is obsolete.

  [Compaq]  On SVID2-compatible systems, local timezone information is
  maintained in the kernel, although the information is not as accurate or as
  complete as the information that can be maintained at user level.  On these
  systems, you can use the tzp parameter with gettimeofday() and
  settimeofday() to get and set timezone information in addition to the time.
  The tzp parameter returns a pointer to a timezone structure that contains
  the local timezone expressed in minutes of time westward from Greenwich and
  a flag that, when nonzero, indicates that daylight savings time applies
  locally during some part of the year.	 Note that, if the tzp parameter is
  set to NULL, timezone information is not returned or set.

  [Compaq]  A process must have the sysattr effective privilege to use
  settimeofday().








RETURN VALUES
  Upon successful completion, a value of 0 (zero) is returned.	Otherwise, -1
  is returned and errno is set to indicate the error.


ERRORS
  If the gettimeofday() or settimeofday() function fails, errno may be set
  the following value:

  [EFAULT]
      [Compaq]	A parameter points to an invalid address.

  [EPERM]
      [Compaq]	The process's effective user ID does not have the sysattr
      effective privilege, which is required for using settimeofday().

SEE ALSO
  Commands:  date(1), zdump(8), zic(8)

  Functions:  adjtime(2), ctime(3), getclock(3), gettimer(3), setclock(3),
  strftime(3), timezone(3)

  Files:  tzfile(4)

  Standards:  standards(5)