diff --git a/reference/datetime/functions/mktime.xml b/reference/datetime/functions/mktime.xml index 81a833307f..5458fa53da 100644 --- a/reference/datetime/functions/mktime.xml +++ b/reference/datetime/functions/mktime.xml @@ -1,5 +1,5 @@ - + @@ -38,23 +38,23 @@ is_dst can be set to 1 if the time is - during daylight savings time, 0 if it is not, or -1 (the default) + during daylight savings time (DST), 0 if it is not, or -1 (the default) if it is unknown whether the time is within daylight savings time or not. If it's unknown, PHP tries to figure it out itself. This can cause unexpected (but not incorrect) results. + + Some times are invalid if is_dst is set to 1. If + DST is enabled in e.g. 2:00, all times between 2:00 and 3:00 are invalid + and mktime returns an undefined (usually negative) + value. Some systems (e.g. Solaris 8) enable DST at midnight so time 0:30 + of the day when DST is enabled is evaluated as 23:30 of the previous day. + is_dst was added in 3.0.10. - - Some times are invalid if DST is on. If DST is enabled in e.g. 2:00, all - times between 2:00 and 3:00 are invalid and mktime - returns undefined (usually negative) value. Some systems (e.g. Solaris 8) - enable DST in midnight so time 0:30 of the day when DST is enabled is - evaluated as 23:30 of the previous day. - mktime is useful for doing date arithmetic and validation, as it will automatically calculate the correct