How to use . h files in c language?

Question

I would like to know which is the most recommended use of the files *.h? Because I don’t know if I can use them just to get the prototype of the functions or the full function.

Answer 1

Most . h files serve only to reference a method that is in a . c, . a , . so, . o or . dll, plus it doesn’t stop you from putting the features inside them, it’s just not semantically correct. an example for use is like this...

file. h

#ifndef  FILE_H
#define  FILE_H

    #include <stdio.h>
    #include <malloc.h>
    #include <stdarg.h>
    #include <unistd.h>
    #include <string.h>

    void method_01(void);
    int method_02(int , int);
    const char * method_return_string();

#endif  /*FILE_H*/

file. c

#include "file.h"

void method_01(void){
    puts("method called...");
}

int method_02(int x, int y){
    return x+y;
}

const char method_return_string(){
    char *c = (char*) malloc(sizeof(char)*60);
    strcat(c,"my text");

    return c;
}