copying unknown datatypes

[DevLip]

I have a variable in a templated class (A) that I want to be able to change from a wrapper class (B). The data type of A changes with each instance (string, int, float...), but what I'm wondering is if I can create a universal member function in B that will set the value in A?
would it be possible to

a = malloc(sizeof(*newVal));
strcpy(a, newVal);

where

template <class T>
class A
{
public:
T * a;
}

and

void * newVal;

is this possible? and am I making sense?