The generic pointer type
Examine the generic pointer type void*.
C++ Generic Pointer Type
void is used as the return type of a function not returning a value and to indicate an empty argument list to a function.
More important in C++, however, is the use of
void* as a generic pointer type.
A generic pointer can be assigned a pointer value of any type, but it may not be dereferenced. It would not make sense to dereference a
pointer to a
Unlike ANSI C, a generic pointer is not assignment-compatible with an arbitrary pointer type. This means C++ requires that generic pointers be
cast to an explicit type for assignment to a nongeneric pointer value.
Here are some examples of legal and illegal expressions stemming from the use of
void* gp; //generic pointer
int* ip; //int pointer
char* cp; //char pointer
gp = ip; //legal conversion
ip = static_cast<int*>(gp); //explicit cast required
//in C++ but not in C
cp = ip; //illegal conversion
*ip = 15; //legal dereference of pointer to int
*ip = *gp; //illegal generic pointer dereference