Regarding this statement from PERLDOC PERLVMS:
The element "$ENV{DEFAULT}" is special: when read, it returns
Perl's current default device and directory, and when set, it
resets them, regardless of the definition of PERL_ENV_TABLES. It
cannot be cleared or deleted; attempts to do so are silently
ignored.
In 5.6.1, at least, it looks like the act of evaluating "keys(%ENV)"
makes this no longer true:
<quote>
$ SHOW DEFAULT
$1$DUA700:[SYS_SCRATCH]
$ SHOW LOGICAL DEFAULT
"DEFAULT" = "FOO" (LNM$PROCESS_TABLE)
$ perl -e "print ""\n$ENV{DEFAULT}\n\n"" "
$1$DUA700:[SYS_SCRATCH]
$ perl -e "@var = keys(%ENV); print ""\n$ENV{DEFAULT}\n\n"" "
FOO
$ perl -v
This is perl, v5.6.1 built for VMS_AXP
...
$ WRITE SYS$OUTPUT "VMS Version " + f$getsyi ("version")
VMS Version V7.2-2
</quote>
I came across this because Env::import evaluates "keys(%ENV)" -- but
only if you don't specify specific variables you want it to tie. So I
think the same change in behavior will occur if you have "use Env;"
anywhere in your program. (But the effects are only visible if you also
have defined "DEFAULT" as a logical.)
One could regard this as a feechur, giving access to the otherwise
hidden logical name "DEFAULT"; but ... especially since Cwd::cwd, on
VMS, relies on the above-quoted statement's being true ... let's not,
OK?
/ Tom Edelson
VMS/Unix Release Engineering
SAS Institute, Inc.
