Actually you might want to use:

use POSIX qw( tzset )

sub localtime_in { local $ENV{TZ} = shift; tzset; localtime }

$localtime_in_EST = localtime_in( "EST" );
[download]

Otherwise you've globally change the timezone for any other calls to (gm|local)time elsewhere in your code.

And personally I've used both some variant of twiddling $ENV{TZ} like this and DateTime.

Localising the $ENV{TZ} isn't sufficient to prevent the effect being global, tzset() will need to be called after the value has been reverted to restore the timezone used by localtime(). For example:

use POSIX qw(tzset);
use strict;
                                                                      
+          
print scalar localtime();
                                                                      
+          
sub localtime_in
{
   local $ENV{TZ} = 'EST';
                                                                      
+          
   tzset();
                                                                      
+          
   localtime();
}
                                                                      
+          
print scalar localtime_in();
print scalar localtime();
[download]

Off the top of my head a way of fixing that would be something like:

use POSIX qw(tzset);
use strict;
                                                                      
+          
print scalar localtime();
                                                                      
+          
sub localtime_in
{
   my $rc;
   my @rc;
   {
     local $ENV{TZ} = shift;
     tzset();
     wantarray ? @rc = localtime() : $rc = localtime();
   }
   tzset();
   return wantarray ? @rc : $rc;
}
                                                                      
+          
print scalar localtime_in('EST');
print scalar localtime();
[download]

/J\

Doesn't seem to work for me using ActivePerl v5.8.7 build 813 under Windows Server 2003. I do get the local time no matter whether I set $ENV{TZ} to EST or CET (my timezone). Tried even localtime_in( "0500" );

Update: The DateTime solution works though. So if you need to make portable code, use DateTime;

Jenda


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You've got your explanation right in your post. Wintendo POSIX support is notoriously flakey to non-existent. I'd bet the DateTime solutions would still work.