73 lines
2.3 KiB
C
73 lines
2.3 KiB
C
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/*
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FUNCTION
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<<tzset>>---set timezone characteristics from TZ environment variable
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INDEX
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tzset
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ANSI_SYNOPSIS
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#include <time.h>
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void tzset(void);
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void _tzset_r (struct _reent *);
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TRAD_SYNOPSIS
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#include <time.h>
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void tzset();
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void _tzset_r (reent_ptr)
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struct _reent *reent_ptr;
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DESCRIPTION
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<<tzset>> examines the TZ environment variable and sets up the three
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external variables: <<_timezone>>, <<_daylight>>, and <<tzname>>. The
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value of <<_timezone>> shall be the offset from the current time zone
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to GMT. The value of <<_daylight>> shall be 0 if there is no daylight
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savings time for the current time zone, otherwise it will be non-zero.
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The <<tzname>> array has two entries: the first is the name of the
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standard time zone, the second is the name of the daylight-savings time
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zone.
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The TZ environment variable is expected to be in the following POSIX
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format:
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stdoffset1[dst[offset2][,start[/time1],end[/time2]]]
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where: std is the name of the standard time-zone (minimum 3 chars)
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offset1 is the value to add to local time to arrive at Universal time
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it has the form: hh[:mm[:ss]]
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dst is the name of the alternate (daylight-savings) time-zone (min 3 chars)
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offset2 is the value to add to local time to arrive at Universal time
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it has the same format as the std offset
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start is the day that the alternate time-zone starts
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time1 is the optional time that the alternate time-zone starts
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(this is in local time and defaults to 02:00:00 if not specified)
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end is the day that the alternate time-zone ends
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time2 is the time that the alternate time-zone ends
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(it is in local time and defaults to 02:00:00 if not specified)
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Note that there is no white-space padding between fields. Also note that
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if TZ is null, the default is Universal GMT which has no daylight-savings
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time. If TZ is empty, the default EST5EDT is used.
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The function <<_tzset_r>> is identical to <<tzset>> only it is reentrant
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and is used for applications that use multiple threads.
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RETURNS
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There is no return value.
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PORTABILITY
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<<tzset>> is part of the POSIX standard.
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Supporting OS subroutine required: None
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*/
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#include <_ansi.h>
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#include <reent.h>
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#include <time.h>
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#include "local.h"
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_VOID
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_DEFUN_VOID (tzset)
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{
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_tzset_r (_REENT);
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}
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