workbench/network/stacks/AROSTCP/netlib/gettimeofday.c

   1 /* $Id$
   2  *
   3  *      gettimeofday.c - get time of the day
   4  *
   5  *      Copyright © 1994 AmiTCP/IP Group,
   6  *                       Network Solutions Development Inc.
   7  *                       All rights reserved.
   8  */
   9
  10 #include <sys/param.h>
  11 #include <sys/time.h>
  12
  13 /****** net.lib/gettimeofday *********************************************
  14
  15     NAME
  16         gettimeofday - get date and time
  17
  18     SYNOPSIS
  19         #include <sys/time.h>
  20
  21         error = gettimeofday(tp, tzp)
  22
  23         int gettimeofday(struct timeval *, struct timezone *)
  24
  25     FUNCTION
  26         The system's notion of the current Greenwich time and the
  27         current time zone is obtained with the gettimeofday() call.
  28         The time is expressed in seconds and microseconds since
  29         midnight (0 hour), January 1, 1970.  The resolution of the
  30         system clock is hardware dependent. If tzp is zero, the time
  31         zone information will not be returned. Also, if your system
  32         software is unable to provide time zone information, the
  33         structure pointed by tzp will be filled with zeroes.
  34
  35     PORTABILITY
  36         UNIX
  37
  38     INPUTS
  39         The structures pointed to by tp and tzp are defined in
  40         <sys/time.h> as:
  41
  42              struct timeval {
  43                   long tv_sec;      \* seconds since Jan. 1, 1970 *\
  44                   long tv_usec;     \* and microseconds *\
  45              };
  46
  47              struct timezone {
  48                   int  tz_minuteswest;   \* of Greenwich *\
  49                   int  tz_dsttime;  \* type of dst correction to apply *\
  50              };
  51
  52         The timezone structure indicates the local time zone (meas-
  53         ured in minutes of time westward from Greenwich), and a flag
  54         that, if nonzero, indicates that Daylight Saving time
  55         applies locally during the appropriate part of the year.
  56
  57     RESULT
  58         Returns 0 when successful and -1 with specific error code in
  59         errno in case of an error. No error codes are specified,
  60         however.
  61
  62     NOTES
  63         gettimeofday() uses GetSysTime() function of the timer.device,
  64         which is new to V36 of the device.
  65
  66         Time zone information is taken from the locale.library, if it
  67         is available (it is included in all Amiga systems from 2.1 and
  68         up). Otherwise the environment variable "TZ" is consulted. If
  69         it fails, the time zone is initialized to the GMT.
  70
  71         Global variable TimerBase _must_ be initialized before
  72         gettimeofday() is called. This is normally done automatically
  73         by the autoinit module (timerinit.c) included in the net.lib.
  74
  75     SEE ALSO
  76         timer.device/GetSysTime()
  77 *****************************************************************************
  78 *
  79 */
  80
  81 /*
  82  * See timerinit.c for comments on these
  83  */
  84 extern struct timezone __time_zone;
  85 extern long __local_to_GMT;
  86
  87 int
  88 gettimeofday(struct timeval *tp, struct timezone *tzp)
  89 {
  90   if (tp) {
  91     GetSysTime(tp);
  92     tp->tv_sec += __local_to_GMT;
  93   }
  94   if (tzp) {
  95     /*
  96      * __time_zone is set up in the timerinit.c
  97      */
  98     *tzp = __time_zone;
  99   }
 100
 101   return 0;
 102 }