...
Effective type of an object is defined as either its declared type or (in case its type hasn't been declared) the effective type of the value assigned to it. In the examples below, we have used terms like 'effective type of pointer p' which implies that if the type of 'p' has been declared (eg: char *p) then that type (in this case char) is the effective type of the pointer. If the type is not declared (eg: void *p) and then the pointer is assigned a value (p = obj), then the effective type of 'p' is the effective type of 'obj'.
Description:
C library functions that make changes to arrays or objects usually take at least two arguments: i.) a pointer to the array/object ii.) an integer indicating the number of elements or bytes to be manipulated. If the arguments are supplied improperly during such a function call, the function may cause the pointer to not point to the object at all or point past the end of the object. This would lead to undefined behavior.
...