diff --git a/newlib/libc/time/tzset.c b/newlib/libc/time/tzset.c index 3b4c01c660a4..77accbfb0485 100644 --- a/newlib/libc/time/tzset.c +++ b/newlib/libc/time/tzset.c @@ -1,6 +1,6 @@ /* FUNCTION -<>---set timezone characteristics from TZ environment variable +<>---set timezone characteristics from <[TZ]> environment variable INDEX tzset @@ -13,36 +13,84 @@ SYNOPSIS void _tzset_r (struct _reent *<[reent_ptr]>); DESCRIPTION -<> examines the TZ environment variable and sets up the three -external variables: <<_timezone>>, <<_daylight>>, and <>. The -value of <<_timezone>> shall be the offset from the current time zone -to GMT. The value of <<_daylight>> shall be 0 if there is no daylight -savings time for the current time zone, otherwise it will be non-zero. -The <> array has two entries: the first is the name of the -standard time zone, the second is the name of the daylight-savings time -zone. - -The TZ environment variable is expected to be in the following POSIX -format: - - stdoffset1[dst[offset2][,start[/time1],end[/time2]]] - -where: std is the name of the standard time-zone (minimum 3 chars) - offset1 is the value to add to local time to arrive at Universal time - it has the form: hh[:mm[:ss]] - dst is the name of the alternate (daylight-savings) time-zone (min 3 chars) - offset2 is the value to add to local time to arrive at Universal time - it has the same format as the std offset - start is the day that the alternate time-zone starts - time1 is the optional time that the alternate time-zone starts - (this is in local time and defaults to 02:00:00 if not specified) - end is the day that the alternate time-zone ends - time2 is the time that the alternate time-zone ends - (it is in local time and defaults to 02:00:00 if not specified) - -Note that there is no white-space padding between fields. Also note that -if TZ is null, the default is Universal GMT which has no daylight-savings -time. If TZ is empty, the default EST5EDT is used. +<> examines the <[TZ]> environment variable and sets up the three +external variables: <<_timezone>>, <<_daylight>>, and <>. +The value of <<_timezone>> shall be the offset from the current time +to Universal Time. +The value of <<_daylight>> shall be 0 if there is no daylight savings +time for the current time zone, otherwise it will be non-zero. +The <> array has two entries: the first is the designation of the +standard time period, the second is the designation of the alternate time +period. + +The <[TZ]> environment variable is expected to be in the following POSIX +format (spaces inserted for clarity): + + <[std]> <[offset1]> [<[dst]> [<[offset2]>] [,<[start]> [/<[time1]>], <[end]> [/<[time2]>]]] + +where: + +<[std]> is the designation for the standard time period (minimum 3, +maximum <> bytes) in one of two forms: + +*- quoted within angle bracket '<' '>' characters: portable numeric +sign or alphanumeric characters in the current locale; the +quoting characters are not included in the designation + +*- unquoted: portable alphabetic characters in the current locale + +<[offset1]> is the value to add to local standard time to get Universal Time; +it has the format: + + [<[S]>]<[hh]>[:<[mm]>[:<[ss]>]] + + where: + + <[S]> is an optional numeric sign character; if negative '-', the + time zone is East of the International Reference + Meridian; else it is positive and West, and '+' may be used + + <[hh]> is the required numeric hour between 0 and 24 + + <[mm]> is the optional numeric minute between 0 and 59 + + <[ss]> is the optional numeric second between 0 and 59 + +<[dst]> is the designation of the alternate (daylight saving or +summer) time period, with the same limits and forms as +the standard time period designation + +<[offset2]> is the value to add to local alternate time to get +Universal Time; it has the same format as <[offset1]> + +<[start]> is the date in the year that alternate time starts; +the form may be one of: +(quotes "'" around characters below are used only to distinguish literals) + + <[n]> zero based Julian day (0-365), counting February 29 Leap days + + 'J'<[n]> one based Julian day (1-365), not counting February 29 Leap + days; in all years day 59 is February 28 and day 60 is March 1 + + 'M'<[m]>'.'<[w]>'.'<[d]> + month <[m]> (1-12) week <[w]> (1-5) day <[d]> (0-6) where week 1 is + the first week in month <[m]> with day <[d]>; week 5 is the last + week in the month; day 0 is Sunday + +<[time1]> is the optional local time that alternate time starts, in +the same format as <[offset1]> without any sign, and defaults +to 02:00:00 + +<[end]> is the date in the year that alternate time ends, in the same +forms as <[start]> + +<[time2]> is the optional local time that alternate time ends, in +the same format as <[offset1]> without any sign, and +defaults to 02:00:00 + +Note that there is no white-space padding between fields. Also note that +if <[TZ]> is null, the default is Universal Time which has no daylight saving +time. If <[TZ]> is empty, the default EST5EDT is used. The function <<_tzset_r>> is identical to <> only it is reentrant and is used for applications that use multiple threads.