Overloading assignment operator

[Hounddog]

I'm trying to write a program that simulates a small memory manager. By the bounds of the problem I have

namespace myNamespace {
   const int MAX = 65536;
   char memory[MAX];

   //initialize the memory
   void init();

   //allocates memory from memory[] and returns a pointer 
   //to the position in the array
   void* allocate(int size);

   ...
}

Is there a way to overload an assignment operator such that

using namespace myNamespace;
int* ptr = (int*)allocate(sizeof(int));
*ptr = 3;

calls my own function, instead of the standard? I'm most worried about the second line, since I'm trying to prevent data from overwriting unallocated memory.

I feel like this is impossible since the assignment operator is non-static member, but I can't find anything that tells me one way or another. Help?

[hamsterman]

You don't need to overload =operator. You have to overload allocate function (which you can't really do the way you want to). you could overload 'new' but that would be a bad idea if you ever needed to call the real one...
You should write a separate function to do this. Something like void* AllocMemory(int size).
Good luck

[Hounddog]

I'm sorry, I guess what wasn't very clear. I've got the allocate function created, I don't need to worry about that. I'm not using "new" or dynamically allocating memory--the "allocate" function (which I've already written) sets aside "size" number of bytes from the memory[] array as "allocated memory," while the rest of the array is "unallocated memory." The kind of thing I'm trying to prevent is:

int* ptr = (int*)allocate(1);
ptr=3;

Unless ints are only one byte long on your system, the assignment here is going to overrun the memory allocated for it. I could always create a "checker" function, like

int* ptr = (int*)allocate(1);
ptr=3;
checkForOverruns(ptr);

but that is contingent on the developer remembering to call that after every assignment--hence why I was looking to overload the assignment operator.

[jsmith]

There isn't for POD types.

[Hounddog]

I didn't think so, but I couldn't find anything confirming that. Thanks.

[Dudester]

Could you use a template of this function and have the template determine the size correctly without the user potentially messing up? Doing a template would also mean being able to output a pointer of the type you are inputting rather than having to cast it after allocating the space.

[Hounddog]

Unfortunately not...I have to use the function as defined in the first post. Good idea though!

At this point, I think I'm just going to define a checkForOverruns function. It's not as elegant as overriding an assignment operator, but it looks like the best I'm going to be able to do.

[guestgulkan]

I was going to suggest that you define your own pointer class.
Your allocate function would return this particular type of pointer.

Thinking about it - this could tie in with using templates but Dudester has already suggested that.