Printable View
Is there some way that I can "hook" a variable so that when it's value changes, some sort of callback is called that lets me know? I thought of making a loop that constantly checks the variable in a different thread, but this would hurt performance pretty bad. Is there a way I can accomplish this without sacrificing much performance?
Implement the Observer design pattern.
Keep the the value in an observable class and have the observers register themselves with the observable. When it changes, call observer->notify(), or whatever you name it, for all registered observers.
No portable way to even go about that that I know of.
Your best bet is to monitor the variable by way of a class or a function, but I suspect you're trying to monitor a variable in another application.
The thing is I want a DLL to automatically free resources that it's user-app created. It would do this when the specified pointer changed to something else. So I guess it's actually a local variable. Do you know of a better way of doing this? (The "Observer design pattern" appears to be out of my league!)
Can't be done. On a limited number of variables within one process, you could, at least in theory (and limiited to certain processor architectures) set up a memory write breakpoint, but that's only useful for up to 4 memory addresses in x86 - other processors may have a different number, but it's not going to work for 100s or 1000s of pointers.
--
Mats