String Pointers

BlitzMax Forums/BlitzMax Programming/String Pointers

BLaBZ

(Posted 2012) [#1]

I'm trying to change a strings value via pointers but for some reason this isn't working..

Local str:String = "Hello World!"

test(Varptr str)

Print str


Function test(x:Byte Ptr)
	Local newStr:String = "CHANGED!"
	x = Varptr newStr
End Function

col	(Posted 2012) [#2]

To do what you're trying to do you pass the 'object' in this case the String by reference using the Var keyword :

Local str:String = "Hello World!"

test(str)

Print str


Function test(strPtr:String Var)
	Local newStr:String = "CHANGED!"
	strPtr = newStr
End Function

BLaBZ

(Posted 2012) [#3]

Oh awesome, What's the difference between Var and Varptr?

Does var pass the argument in as a reference?

col	(Posted 2012) [#4]

Var is by reference, yep.
Varptr is usually used with a Ptr type variable, effectively giving you a new variable that is a pointer to a variable. In your case you want to change the value of the original variable itself, but in your example you were changing the value of the pointer to the variable.

EDIT: edited for better a explanation.

Last edited 2012