my_sub( @a );

# ...

sub my_sub {
  # here the localized @_ variable contains references to
  # the list of values passed as paramters,
  for my $i (0 .. $#_) {
    print "param $i = $_[$i]\n";
  }
}

# OUTPUT
# param 0 = a
# param 1 = b
# param 2 = c