# As a pragma:
use diagnostics;
use diagnostics -verbose;

enable  diagnostics;
disable diagnostics;

# As a program:
$ perl program 2>diag.out
$ splain [-v] [-p] diag.out
*****
use diagnostics;
*****
no diagnostics
*****
BEGIN { $diagnostics::PRETTY = 1 }
*****
use diagnostics -verbose
*****
use diagnostics;
print NOWHERE "nothing\n";
print STDERR "\n\tThis message should be unadorned.\n";
warn "\tThis is a user warning";
print "\nDIAGNOSTIC TESTER: Please enter a <CR> here: ";
my $a, $b = scalar <STDIN>;
print "\n";
print $x/$y;
*****
perl -w test.pl 2>test.out
./splain < test.out
*****
perl -w -Mdiagnostics test.pl
*****
use diagnostics; # checks entire compilation phase
print "\ntime for 1st bogus diags: SQUAWKINGS\n";
print BOGUS1 'nada';
print "done with 1st bogus\n";

disable diagnostics; # only turns off run-time warnings
print "\ntime for 2nd bogus: (squelched)\n";
print BOGUS2 'nada';
print "done with 2nd bogus\n";

enable diagnostics; # turns back on run-time warnings
print "\ntime for 3rd bogus: SQUAWKINGS\n";
print BOGUS3 'nada';
print "done with 3rd bogus\n";

disable diagnostics;
print "\ntime for 4th bogus: (squelched)\n";
print BOGUS4 'nada';
print "done with 4th bogus\n";