Re: zonefile changes and long running processes.

[Paul Eggert <eggert at cs dot ucla dot edu>]

Carlos O'Donell wrote:
> That is not correct, tzset is MT-safe, and documented in the glibc
> manual as such.

Sorry, my use of the term "thread-safe" was incorrect.  I was thinking 
of the problem of ensuring that a thread that calls localtime_r is 
insulated from another thread simultaneously calling tzset, i.e., that 
the tzset will appear to occur either all before or all after the 
localtime_r.  As far as I know MT-Safe does not imply this sort of 
atomicity, so an application cannot assume it.

> Having tzset be MT-safe will not slow down localtime_r

Wouldn't having tzset and localtime_r exclude each other slow down 
localtime_r?  And if they don't exclude each other, shouldn't 
application writers avoid the abovementioned situation if they want 
localtime_r's results to be reliable?

Please bear with me here, as I'm by no means an expert on the various 
aspects of thread-safety in glibc.