wantarray

• wantarray

  Returns true if the context of the currently executing subroutine or eval is looking for a list value. Returns false if the context is looking for a scalar. Returns the undefined value if the context is looking for no value (void context).

      return unless defined wantarray; # don't bother doing more
      my @a = complex_calculation();
      return wantarray ? @a : "@a";

  wantarray's result is unspecified in the top level of a file, in a BEGIN, UNITCHECK, CHECK, INIT or END block, or in a DESTROY method.

  This function should have been named wantlist() instead.