What is forward reference in C?

What is forward reference in C with respect to pointers?

Can I get an example?

See this page on forward references. I don't see how forward referencing would be different with pointers and with other PoD types.

Note that you can forward declare types, and declare variables which are pointers to that type:

struct MyStruct;
struct MyStruct *ptr;
struct MyStruct var;  // ILLEGAL
ptr->member;  // ILLEGAL

struct MyStruct {
    // ...
};

// Or:

typedef struct MyStruct MyStruct;
MyStruct *ptr;
MyStruct var;  // ILLEGAL
ptr->member;  // ILLEGAL

struct MyStruct {
    // ...
};

I think this is what you're asking for when dealing with pointers and forward declaration.