Build an array of pointers from existing pointers - objective-c

Question

I have a class which must initialize a group of similar objects the same way.
NSNumber *a = nil;
NSNumber *b = nil;
NSNumber *c = nil;
a, b and c are member variables of an existing object. In my code I use a more complex NSObject subclass, but this example is easier to understand using NSNumbers.
All 3 objects must be initialized in a similar way. Therefore I want to build an array of pointers which I can use within a for-loop like this:
NSPointerArray *objs = [NSPointerArray weakObjectsPointerArray];
[objs addPointer:&a];
[objs addPointer:&b];
[objs addPointer:&c];
Running the above code I get the following error:
error: address doesn't contain a section that points to a section in a object file
How can I build an array which I can explore with a loop like this?
for (id *o in objs) {
*o = #2;
}

Answer 1

just wrap the pointers in 'NSValue' objects and you're good
id v1 = [NSValue valueWithPointer:p1];
id v2 = [NSValue valueWithPointer:p2];
id v3 = [NSValue valueWithPointer:p3];
id array = #[v1,v2,v3];
for(NSValue *value in array) {
void *pointer = value.pointerValue;
NSNumber *n = (__bridge NSNumber*)pointer;
}
demo for what YOU want to do it appears: (NSNumbers are immutable)
#import <Foundation/Foundation.h>
int main(int argc, char *argv[]) {
#autoreleasepool {
NSNumber *a;
NSNumber *b;
NSArray *os = #[ [NSValue valueWithPointer:&a],
[NSValue valueWithPointer:&b] ];
for (NSValue *v in os) {
void *pointer = [v pointerValue];
NSNumber **n_ptr = (__bridge NSNumber**)pointer;
*n_ptr = #2.0;
}
NSLog(#"%# %#", a,b);
}
}