Local variables V GetTriggerUnit()

02-27-2014, 10:37 PM

At what point does it become better (read: faster) to use a local variable to store an event variable rather than using the function call?

e.g.

JASS:

private function Actions takes nothing returns nothing
    local unit c = GetTriggerUnit()
    call IssueLastOrder(c)
    call UnitAddBuff(c, c, BUFF_TYPE_SOMETHING, DURATION, 1)
    set c = null
endfunction

JASS:

private function Actions takes nothing returns nothing
    call IssueLastOrder(GetTriggerUnit())
    call UnitAddBuff(GetTriggerUnit(), GetTriggerUnit(), BUFF_TYPE_SOMETHING, DURATION, 1)
endfunction

Is it after you would use the function X times or does it depend on other stuff?
I know the first is less function calls but is that outweighed by having to create and null a local variable?

02-28-2014, 06:35 AM	#2
DioD	benchmark it.

02-28-2014, 07:32 AM

PurgeandFire111

Last time I benched it, it was 2 times. Local declaration is fast, and so is nulling it. So usually I'll call the same function within a function 2 times at most. iirc, the difference between something like this was pretty negligble:

JASS:

call BJDebugMsg(GetUnitName(GetTriggerUnit()) + GetUnitName(GetTriggerUnit()))

// ... vs ...

local unit u = GetTriggerUnit()
call BJDebugMsg(GetUnitName(u) + GetUnitName(u))
set u = null

(that code is just an example, not the actual code I used). I don't remember which one is necessarily faster. When you have 3 function calls vs. a local declaration, I'm 90% certain that the local declaration was the faster option.

... But all this is just from my memory, which can be foggy. Sadly, I can't test it (yay Macs).