Howto: C++ function that adjusts its return type to the callers needs

I have a malloc like function:

void * MyMalloc(size_t size) { return malloc(size); }

Now to use this for let's say a char * type;

char * charPointer = static_cast<char *>(MyMalloc(100));

How to get rid of the cast?

I can do this:

template<typename T> T MyMalloc(size_t size) {return static_cast<T>(MyMalloc(size));}

And the callling code is:

char * charPointer = MyMalloc<char *>(100);

This looks better, but is there a way to let the compiler do this for me? Similar to auto, but my understanding of auto is that auto is determined by the return / assignment type not the needs of the caller.

What I want the calling code to look like is :

char * charPointer = MyMalloc(100);

Of course code like this would not work (and I would not want it to):

int val = MyMalloc(100);

I am not sure this can be done, but it it can be done, I'm sure somebody here knows. Ty

You can use a class type for this. Classes can have a template conversion operator that will deduce the type you whish to convert to based on the expression it is used in. That gives you a class that looks like

class MyMalloc
{
public:
    MyMalloc(std::size_t size) : ptr(malloc(size)) {}
    template <typename T>
    operator T() { return static_cast<T>(ptr); }
private:
    void* ptr;
};

and this lets you use it like

int main()
{
    char * charPointer = MyMalloc(100);
}

which you can see working in this live example.