Re: Passing Parameter as Variable vs as address of variable

On 2023-08-25 10:23 a.m., Vinay Gavankar wrote:

Since RPG internally passes the parm as an address of the variable, is
there any performance advantage in passing the address of the variable as a
parm instead of the variable itself when the variable is large (say 2K).
...

If you're asking about passing the address of a variable by value vs passing the variable by reference ...

They both behave the same, with the same performance. But passing a variable by reference is generally good and passing its address by value is generally bad.

dcl-pr p1;
salary packed(9:2);
end-pr;
dcl-s emp_sal packed(9:2);
p1 (emp_sal);

dcl-pr p2;
salary pointer value;
end-pr;
dcl-s emp_sal packed(9:2);
p2 (%addr(emp_sal));

The problem with p2 is that the compiler can't help you pass the correct parameter.

dcl-s emp_name varchar(20);

p1 (emp_name);
- You will get an error at compile time. That is good.

p2 (%addr(emp_name));
- The program will compile, but it will have a bug. It is always harder to find the cause of a bug at runtime than at compile time.