use constant MAX_INT => unpack('J', pack('j', -1));
use constant MAX_INT => 0+sprintf('%u', -1);

##</code><code>##

for (my $_ = 1; ; ++$_)

##</code><code>##

$ perl -e'Inf()'
Undefined subroutine &main::Inf called at -e line 1.

$ perl -Mstrict -e'Inf'
Bareword "Inf" not allowed while "strict subs" in use at -e line 1.
Execution of -e aborted due to compilation errors.