Header only library doesn't use header guards. How can I use the library in other header files?

Question

I'm working with a header only library ( Nuklear ). I include this in my main.c file like so:

#define SDL_MAIN_HANDLED
#include <GL/glew.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_opengl.h>

#define NK_INCLUDE_FIXED_TYPES
#define NK_INCLUDE_STANDARD_IO
#define NK_INCLUDE_STANDARD_VARARGS
#define NK_INCLUDE_DEFAULT_ALLOCATOR
#define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
#define NK_INCLUDE_FONT_BAKING
#define NK_INCLUDE_DEFAULT_FONT
#define NK_IMPLEMENTATION
#define NK_SDL_GL3_IMPLEMENTATION
#include "nuklear.h"
#include "nuklear_sdl_gl3.h"

I want to create a file to house some components and break the code up into smaller chunks. I tried to do this by including nuklear.h into one of the component headers but got a re declaration error:

error: redefinition of 'nk_sdl_shutdown'

I don't know any other way to access the types from nuklear.h in other header files. Any help please?

Answer 1

You can wrap the #include for that library in another header.

#ifndef NUKLEAR_INCLUDED
#define NUKLEAR_INCLUDED

#define NK_INCLUDE_FIXED_TYPES
#define NK_INCLUDE_STANDARD_IO
#define NK_INCLUDE_STANDARD_VARARGS
#define NK_INCLUDE_DEFAULT_ALLOCATOR
#define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
#define NK_INCLUDE_FONT_BAKING
#define NK_INCLUDE_DEFAULT_FONT
#define NK_IMPLEMENTATION
#define NK_SDL_GL3_IMPLEMENTATION
#include "nuklear.h"
#include "nuklear_sdl_gl3.h"

#endif

Answer 2

It looks like it does include header guards now. Try updating the library. If that doesn't work file a bug or, even better, a pull request.

It's open source software, if you find something wrong you can fix it instead of trying to work around the problem.