stb_ds multiple definition error

[Aragami1408]

Hi there, I'm trying to use stb_ds's dynamic array in my project. Here's the source code below:

rom.h:

#ifndef ROM_H
#define ROM_H

#include "types.h"


static const u8 NES_TAG[4] = {0x4E, 0x45, 0x53, 0x1A};
static const unsigned int PRG_ROM_PAGE_SIZE = 16384;
static const unsigned int CHR_ROM_PAGE_SIZE = 8192;

typedef struct rom rom_t;
typedef enum mirroring mirroring_t;

enum mirroring {
	VERTICAL,
	HORIZONTAL,
	FOUR_SCREEN
};

struct rom {
	u8 *prg_rom;
	u8 *chr_rom;
	u8 mapper;
	mirroring_t screen_mirroring;
};

rom_t *rom_init(u8 *raw);
void rom_free(rom_t *rom);

#endif

rom.c:

#include "rom.h"

#include <stdlib.h>
#include <stdbool.h>

#define STB_DS_IMPLEMENTATION
#include <stb/stb_ds.h>

rom_t *rom_init(u8 *raw) {
	rom_t *rom = malloc(sizeof(rom_t));
	for (int i = 0; i < 4; i++) {
		if (raw[i] != NES_TAG[i]) {
			// TODO: Error Handling
			return NULL;
		}
	}

	u8 mapper = (raw[7] & 0xf0) | (raw[6] >> 4);
	
	unsigned int ines_ver = (raw[7] >> 2) & 3;
	if(ines_ver != 0) {
		// TODO: Error Handling
		return NULL;
	}

	bool four_screen = (raw[6] & 8) != 0;
	bool vertical_mirroring = (raw[6] & 1) != 0;

	mirroring_t screen_mirroring;
	if(four_screen) screen_mirroring = FOUR_SCREEN;
	else if(!four_screen && vertical_mirroring) screen_mirroring = VERTICAL;
	else if (!four_screen && !vertical_mirroring) screen_mirroring = HORIZONTAL;

	unsigned int prg_rom_size = raw[4] * PRG_ROM_PAGE_SIZE;
	unsigned int chr_rom_size = raw[5] * CHR_ROM_PAGE_SIZE;

	bool skip_trainer = (raw[6] & 4) != 0;

	unsigned int prg_rom_start = 16 + ((skip_trainer)? 512: 0);
	unsigned int chr_rom_start = prg_rom_start + prg_rom_size;	
	
	arraddnptr(rom->prg_rom, prg_rom_start + prg_rom_size);
	arraddnptr(rom->chr_rom, chr_rom_start + chr_rom_size);

	for(unsigned int i = prg_rom_start; i < (prg_rom_start + prg_rom_size); i++) arrins(rom->prg_rom, i, raw[i]);
	for(unsigned int i = chr_rom_start; i < (chr_rom_start + chr_rom_size); i++) arrins(rom->prg_rom, i, raw[i]);

	rom->mapper = mapper;
	rom->screen_mirroring = screen_mirroring;

	return rom;
}

void rom_free(rom_t *rom) {
	arrfree(rom->prg_rom);
	arrfree(rom->chr_rom);
	free(rom);	
	rom = NULL;
}

And here is my project's folder structure:

But when I compiled the project it showed like below:

Is there any way to solve this multiple definition error? Thanks in advance

[nothings]

The error messages say it's already defined in bus.c

Read this line of comment very carefully:
https://github.com/nothings/stb/blob/master/stb_ds.h#L9

[Aragami1408]

I got it, but there is a problem in my project:

• bus.c depends on rom.c
• cpu.c depends on bus.c

even when I only define stb_ds in rom.h, the problem still occur, so what am I supposed to do?

[marauder2k7]

use #ifndef to wrap the defines

[nothings]

???

You can put the include in as many C or H files as you like. Just only put the define in one C file. Exactly one, no more, no less.

[Aragami1408]

I did it, thanks for your help, and @lionlai1989 too!

[lionlai1989]

@Aragami1408 Here is what I did. My project structure:

$ ll
total 52
drwxrwxr-x 2 lai lai  4096 Mär 25 09:06 ./
drwxrwxr-x 5 lai lai  4096 Mär 25 09:06 ../
-rw-rw-r-- 1 lai lai  1498 Mär 25 09:03 CMakeLists.txt
-rw-rw-r-- 1 lai lai   132 Mär 25 08:54 define_stb_image.cpp
-rw-rw-r-- 1 lai lai  9556 Mär 25 09:56 image_eigen.cpp
-rw-rw-r-- 1 lai lai   927 Mär 25 09:06 image_eigen.hpp
-rw-rw-r-- 1 lai lai 11661 Mär 25 10:16 image_xtensor.cpp
-rw-rw-r-- 1 lai lai   994 Mär 25 09:58 image_xtensor.hpp

Both image_eigen.cpp and image_xtensor.cpp need stb library. So, in define_stb_image.cpp, it defines the macro and image_eigen.cpp and image_xtensor.cpp links to define_stb_image.cpp with CMake.

$ cat define_stb_image.cpp 
#define STB_IMAGE_IMPLEMENTATION
#include <stb/stb_image.h>
#define STB_IMAGE_WRITE_IMPLEMENTATION
#include <stb/stb_image_write.h>

and in CMakeLists.txt:

add_library(stb_library STATIC)
target_sources(stb_library PUBLIC define_stb_image.cpp)
target_include_directories(stb_library PUBLIC ${CMAKE_SOURCE_DIR}/extern)

add_library(image_eigen STATIC)
target_link_libraries (image_eigen Eigen3::Eigen stb_library)
target_sources(image_eigen PUBLIC image_eigen.cpp)

add_library(image_xtensor STATIC)
target_link_libraries (image_xtensor xtensor xtensor::optimize xtensor::use_xsimd stb_library)
target_sources(image_xtensor PUBLIC image_xtensor.cpp)

Now I can include stb library in both image_eigen.cpp and image_xtensor.cpp as following:

#include <stb/stb_image.h>
#include <stb/stb_image_write.h>

[nothings]

Doing it that way works, but it's not necessary. All you have to do is put the IMPLEMENTATION #define in one and only one C/CPP file.