perl - Force use of flags Getopt::Long -

is there way force use of -flags when reading in command-line arguments using getopt::long? example in current situation:

getoptions('r=s' => \$var1,               'lf=f' => \$var2,               'uf=f' => \$var3,               'trd=i' => \$var4,               'vd=f' => \$var5) or die("$usage"); 

the script not exit or display $usage if arguments still provided without flags (such -lf). instead runs regardless until inevitably errors later on arguments not read respective variables (and may in wrong order).

q: getoptions not return false result when option not supplied

a: that's why they're called 'options'.

source: getopt::long documentation

you add conditionals check value of flags , if not defined call die or call usage.