Hein Ragas writes:
> In example 3 of the perlxstut page, the "round" function, it is shown
> that a constant can not be changed. That's fair enough -- but how can I
> return a "fresh" value back to the calling Perl program? How would the code
> of example 3 have to be modified to be able to do "$i = Mytest::round(4.5)"
> in the test-program?
> I've looked around for this, but all I could find is the OUTPUT-keyword,
> which does exactly the opposite.
int
round(n)
double n
CODE:
RETVAL = n+0.5;
OUTPUT:
RETVAL
Here's the relevant slide from the XS section of our advanced class.
Cheers;
Nat
=Return values
* If your function returns a single value, use RETVAL:
int
is_odd(num)
int num
CODE:
RETVAL = num % 2;
OUTPUT:
RETVAL
* Mark changed parameters in OUTPUT section:
void
triple(num)
int num
CODE:
num *= 3;
OUTPUT:
num
