将静态函数分离到 C 中的另一个（头文件？）文件中

Question

I'm learning how to program in C and came across the following issue. I have some private helper functions that I would not like to expose anywhere. Here is how source files look like:

logic.h :

#ifndef LOGIC_H
#define LOGIC_H

enum logic_type{
    customer_logic = 1,
    requestor_logic,
    company_logic
}

void execute_logic(enum logic_type logic_type);

#endif //LOGIC_H

logic.c :

#include "logic.h"

static void _execute_customer_logic();
static void _execute_requestor_logic();
static void _execute_company_logic();

void execute_logic(enum logic_type logic_type){
    switch(logic_type){
        case customer_logic:
            _execute_customer_logic();
            break;
        case requestor_logic:
            _execute_requestor_logic();
            break;
        case company_logic:
            _execute_company_logic();
            break;
    }
}

void _execute_customer_logic(){
    //very long and complicated function
}

void _execute_requestor_logic(){
    //very long and complicated function
}

void _execute_company_logic(){
    //very long and complicated function
}

With the current design it looks really messy. So I was thinking about putting each logic in a separate private header file and then simply include it. Like

company_logic_internal.h :

#ifndef COMPANY_LOGIC_INTERNAL_H
#define COMPANY_LOGIC_INTERNAL_H

    void _execute_company_logic(){
        //very long and complicated function
    }

#endif //COMPANY_LOGIC_INTERNAL_H

The problem is that I put an implementation into the header file which looks contradictory to the definition of header files which contains function prototypes, but not the actual definition. Making this company_logic.h to be a company_logic.c also looks wierd since it means that .c file will be included.

So I'm kind of confused of how to implement such a thing better.

Answer 1

This not exactly direct answer to the question, but you can try this to avoid unnecessary expose of your code and avoid recompile.

so instead of going for number of header files(.h files), go for .c files, ie, each function can be defined in separate .c files and create static library (ex: company_private.a), you haven't mentioned what compiler you use but with gcc you can control access to the library with visibility option or --exclude-libs (though not sure it is supported with all tool chain) while compilation and link it to the program where you want use those API's.

for simple toy example of creating static library check following link http://www.codingfleets.com/2018/12/how-to-create-static-library-in-c.html

if you are using gcc tool chain, you can find lot of documentation about limiting visibility of symbols online.