Redefinition in C

Question

hello, can somebody explain me about redefinition in C:

is it possible to do something like this

typedef struct NumberContainer* ptrNumberContainer;

and after that

  typedef struct NumberContainer* ptrCall;

may it cause some problems during linkage? thanks in advance

Answer 1

No, that's perfectly OK - you have two synonyms for the same underlying type - this is quite common. However, the practice of hiding the fact that something is a pointer by using a typedef is generally viewed as bad practice in C.

Answer 2

This is not redefinition. Redefinition refers to macro definitions:

#define FOOBAR 1
#undef FOOBAR
#define FOOBAR 2

Answer 3

Of course it's possible. Defines two different type names to mean the same thing.

Answer 4

In that case, ptrCall will actually refer to the same type as ptrNumberContainer. I think they will also be compatible compile time. So you can say, for example:

ptrNumberContainer p1;
ptrCall p2;

Then these will work:

p1 = p2;
*p1 = *p2;