Doesn't this class create a dangling pointer? Topic is solved

[SAbboushi]

Code: Select all

/*
    I'm trying to update Elgin's TypeLib2AHK https://www.autohotkey.com/boards/viewtopic.php?f=6&t=36025

    Amazing piece of code for someone like me needing to learn about UIAutomation.

    Wondering if this class constructor can result in a dangling pointer?  I failed to figure out how I can test for that...
*/

#Persistent
point:=new tagPOINT()
ListVars

class tagPOINT
{
	__New(byref p="empty")
	{
		If (p="empty")
		{
			VarSetCapacity(p,this.__SizeOf(),0)
		}
		ObjInsert(this, "__Value", &p) ; <-- when a parameter is not passed (i.e. p="empty"), isn't this pointing to a string buffer for local variable "p" whose memory will be released after __NEW() returns?  i.e. doesn't this result in a dangling pointer?
	}
}

re: @Elgin's TypeLib2AHK

[swagfag]

yeah, ud have to replace VarSetCapacity with any of the XXXAlloc memory management functions. accessing .__Value after the constructor has returned is undefined behavior
or if ure porting to v2, BufferAlloc doesnt suffer from that issue

[SAbboushi]

Thanks for the confirmation

... or if ure porting to v2, BufferAlloc doesnt suffer from that issue

Yes - trying to update for V2.