sub myCmp {
  $a cmp $b;
}

sub myFunc {
  my($sortFunc, @arr) = @_;

  # do something ...

  @arr = sort $sortFunc @arr;

  # do something else ...

  return(@arr);
}

@tmpArr = ( "xxx", "aaa", "zzz", "bbb" );
@tmpArr = myFunc(\&myCmp, @tmpArr);