cc-preprocessor

How do I `include` custom headers which is inside `includes/` inside `functions/create_note.c`

So this is my source tree for a simple note-taking app I'm creating.

Folder PATH listing for volume Seagate Ext
Volume serial number is 6C91-D326
E:.
ª   .gitignore
ª   README.md
ª   
+---.vscode
ª       c_cpp_properties.json
ª       settings.json
ª       
+---src
    ª   compile.sh
    ª   main.c
    ª   note-taker.config
    ª   
    +---functions
    ª       create_note.c
    ª       delete_note.c
    ª       view_note.c
    ª       
    +---includes
            foo.c
            foo.h
            func.h

Whenever I run gcc main.c includes/foo.c functions/create_note.c functions/view_note.c functions/delete_note.c -o x I'm getting:

functions/create_note.c:7:10: fatal error: includes/foo.h: No such file or directory
 #include "includes/foo.h"
          ^~~~~~~~~~~~~~~~
compilation terminated.
functions/view_note.c:3:10: fatal error: includes/func.h: No such file or directory
 #include "includes/func.h"
          ^~~~~~~~~~~~~~~~~
compilation terminated.
functions/delete_note.c:3:10: fatal error: includes/func.h: No such file or directory
 #include "includes/func.h"
          ^~~~~~~~~~~~~~~~~
compilation terminated.

Inside my create_note.c this is how I've ordered the preprocessors.

#include <io.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>

#include "includes/foo.h"
#include "includes/func.h"

func.h has three functions declared which are all inside functions/, and create_note.c is one of them. The above shows how the preprocessors are inside create_note.c as mentioned. How would I solve the compile error?

I've tried doing this in my #include:

Expectation is: the program should compile successfully and work!

Solution

  • You have two options to solve this.
    OPTION 1:

    assuming you current working directory is src add the -I includes/ flag to gcc this will tell gcc to look for headers in the includes/ directory then you will have to include like this
    #include "func.h" instead of this #include "includes/func.h"

    if you want to include it like #include "includes/func.h" add -I . flag instead
    Here is how the full command would be

    gcc main.c includes/foo.c functions/create_note.c functions/view_note.c functions/delete_note.c -I . -o x

    OPTIONS 2:

    prefix your include headers with ../
    .. means previous dir so to include includes/func.h from functions/create_note.c include this way

    #include "../includes/func.h"

    WHY YOUR CODE DIDN'T GIVE YOU THE EXPECTED RESULT:

    when you type #include "src\include\foo.h" the compiler actually search for the header file in E:\src\functions\src\include which doesn't exist it searches for it relatively to create_note.c

    #include "./includes/foo.h" didn't work for the same reason the only diffrence it was looking in a different directory in this case it was E:\src\functions\includes.