my @x;
print 'my @x;',"\n"; &checkdef;
@x = ();
print '@x = ();',"\n"; &checkdef;
@x = (1);
print '@x = (1);',"\n"; &checkdef;
@x = ();
print '@x = ();',"\n"; &checkdef;
undef @x;
print 'undef @x;',"\n"; &checkdef;
@x = ();
print '@x = ();',"\n"; &checkdef;
sub checkdef {
	if (defined (@x)) {
		print "\@x is defined\n"
	} 
	else {
		print "\@x is undefined\n"
	}

}
__OUTPUT__
my @x;
@x is undefined
@x = ();
@x is undefined
@x = (1);
@x is defined
@x = ();
@x is defined
undef @x;
@x is undefined
@x = ();
@x is undefined