#%ENV

The hash %ENV contains your current environment. Setting a value in ENV changes the environment for any child processes you subsequently fork() off.

As of v5.18.0, both keys and values stored in %ENV are stringified.

my $foo = 1;
$ENV{'bar'} = \$foo;
if( ref $ENV{'bar'} ) {
    say "Pre 5.18.0 Behaviour";
} else {
    say "Post 5.18.0 Behaviour";
}

Previously, only child processes received stringified values:

my $foo = 1;
$ENV{'bar'} = \$foo;

# Always printed 'non ref'
system($^X, '-e',
       q/print ( ref $ENV{'bar'}  ? 'ref' : 'non ref' ) /);

This happens because you can't really share arbitrary data structures with foreign processes.

Perldoc Browser is maintained by Dan Book (DBOOK). Please contact him via the GitHub issue tracker or email regarding any issues with the site itself, search, or rendering of documentation.

The Perl documentation is maintained by the Perl 5 Porters in the development of Perl. Please contact them via the Perl issue tracker, the mailing list, or IRC to report any issues with the contents or format of the documentation.