Paul Eggert wrote: > By the way, what do you need rearguard for? Is this for Java, or > something else?
One reason is for Java. At the same time, it is also to keep the same as other OS vendors (such as RHEL). If switching from rearguard to vanguard now, it might affect upper-layer third-party softwares and require a significant amount of time to explain the differences between these changes. For example, the glibc contains a global variable timezone, which is the opposite value of the gmtoff value in the last line of the timezone with isdst=0. In some time zones, the values of timezone in rearguard and vanguard modes are different. I have seen some softwares directly add or subtract the timezone value to convert the local time to the UTC time. If the mode is switched from rearguard to vanguard, the time calculation will be incorrect.
