Best way to store constant data in C - c

Question

Let's say I'm making a C program which display information about a precious stone when the user enter the stone's name.
The stones names never change and there are less than 20 of them so reading them from a external file at runtime seems a bit overkill.
I also need to access those names from multiple files (let's say two).
What I usually do is I declare a global char * array like so:
char *g_rsc_names[] = {"linemate", "deraumere", "sibur", "mendiane", "phiras", "thystane"};
in the file I need to use those. This look pretty fine to me but this only allow me to access the names in the file where I declare this global array.
In that case, what is the best/cleanest way to store the stones names?

Answer 1

You can wrap your array with a function which returns the const char* to the appropriate stone name and put that declaration into your global header file you include in multiple files:
const char* get_stone_name(size_t id);
Inside a source file define the get_stone_name like:
const char* get_stone_name(size_t id) {
static const char* const names[] = {
"linemate", "deraumere", "sibur", "mendiane", "phiras", "thystane"
};
return (id < (sizeof(names) / sizeof(names[0])) ? names[id] : "");
}
Decaring names as static will guarantee that won't be initialized more than once, and as a side option you can prevent the user to index your array out of bounds.

Answer 2

Define an enum with symbolic names for each stone. You would then store the enum value in the file instead of the name.
You could then define a function which will return the associated string for the given enum.
enum stones {
STONE_LINEMATE,
STONE_DERAMERE,
...
};
const char *stone_name(int stone)
{
switch (stone) {
case STONE_LINEMATE:
return "linemate";
case STONE_DERAMERE:
return "deraumere";
...
default:
return "";
}

Answer 3

Put a public declaration of the stones' data type in a header file, say stones.h:
// This lets any file that includes stones.h know that you've defined
// a variable named g_rsc_names.
extern char const *const g_rsc_names[];
The variable is defined as an array containing some number of character (string) pointers that will never change that each point to characters (strings) that will never change. This is to prevent programmer errors later and gives some hints to your compiler for optimization.
Then, in another file, stones.c:
// Populate the array.
char const *const g_rsc_names[] = {
"linemate", "deraumere", "sibur", "mendiane", "phiras", "thystane"
};
Now, include stones.h wherever you want to reference the array. Make sure to compile the stones.c file and link it to your binary.