Understanding scope and information hiding

We have seen how to cross linkage boundaries with functions by including header files with their prototypes. If we wanted to limit a function's scope to only its compilation unit, we could do that in one of two ways.

The first way is to remove from the header file any function prototypes we do not want to cross the linkage scope. In that way, any other source file that includes the header will not have the excluded function prototype and will, therefore, be unable to call it. For example, in the sortName.c file from Chapter 23, Using File Input and File Output, only the AddName(), PrintNames(), and DeleteNames() functions were ever called from within the main() function. The other functions in nameList.c did not need to be global. Therefore, nameList.h only needs the following:

#include <stdbool.h>
#include <stdlib.h>

typedef char ListData;

typedef struct _Node ListNode;

typedef struct _Node {
ListNode*pNext...