Question

For my upcoming university C project, I’m requested to have modular code as C allows it. Basically, I’ll have .c file and a corresponding .h file for some data structure, like a linked list, binary tree, hash table, whatever…

Using a linked list as an example, I have this:

typedef struct sLinkedList {
    int value;
    struct sLinkedList *next;
} List;

But this forces value to be of type int and the user using this linked list library would be forced to directly change the source code of the library. I want to avoid that, I want to avoid the need to change the library, to make the code as modular as possible.

My project may need to use a linked list for a list of integers, or maybe a list of some structure. But I’m not going to duplicate the library files/code and change the code accordingly.

How can I solve this?

Answer 1

Unfortunately, there is no simple way to solve this. The most common, pure C approach to this type of situation is to use a void*, and to copy the value into memory allocated by you into the pointer. This makes usage tricky, though, and is very error prone.