undefined ImGui symbols when using Vulkan + glfw backend on macOS

[zxubian]

Environment:

• zig
  • v.0.15.1
• vulkan-zig
  • zig-0.15-compat#f879074293f0e2f718c93fd19cc0a96260a3aa52
• zgui
  • zgui-0.6.0-dev--L6sZO_HbQBW30QfIGHgKhjxShc_o4wBeJZ0hga5IA0c
• zglfw
  - zglfw-0.10.0-dev-zgVDNLyhIQCZR_rbIf7hnCKuifzcmPOLOQhd_hrqq8cl
• macOS
  • 15.5
• vulkan SDK
  • 1.3.283.0

Build.zig

const renderer_module = b.addModule(
        "renderer",
        .{
            .root_source_file = b.path("./src/Render/root.zig"),
            .target = target,
            .optimize = optimize,
        },
);

//...

const zgui = b.dependency("zgui", .{
        .target = target,
        .optimize = optimize,
        .backend = .glfw_vulkan,
});
const zgui_module = zgui.module("root");
const imgui = zgui.artifact("imgui");
imgui.addIncludePath(vulkan_headers.path("include"));
renderer_module.addImport("zgui", zgui_module);
renderer_module.linkLibrary(imgui);

Usage

zgui.init(gpa)
zgui.backend.init( zgui.backend.ImGui_ImplVulkan_InitInfo{
    \\ ...
    },
    self.window,
);

Error

renderer-run
└─ run exe renderer
   └─ compile exe renderer Debug native 3 errors
error: undefined symbol: _ImGui_ImplGlfw_InitForVulkan
    note: referenced by .zig-cache/o/2c56902be150a7dd0b46efee7c3f0280/renderer_zcu.o:_backend_glfw.initVulkan
error: undefined symbol: _ImGui_ImplVulkan_CreateFontsTexture
    note: referenced by .zig-cache/o/2c56902be150a7dd0b46efee7c3f0280/renderer_zcu.o:_backend_vulkan.init
error: undefined symbol: _ImGui_ImplVulkan_Init
    note: referenced by .zig-cache/o/2c56902be150a7dd0b46efee7c3f0280/renderer_zcu.o:_backend_vulkan.init
error: the following command failed with 3 compilation errors:

[zxubian]

Confirmed that above functions are included in libimgui.a, but the names are mangled:

BEFORE

nm libimgui.a | grep InitFor
00000000000018c8 T __Z27ImGui_ImplGlfw_InitForOtherP10GLFWwindowb
00000000000014cc T __Z28ImGui_ImplGlfw_InitForOpenGLP10GLFWwindowb
0000000000001894 T __Z28ImGui_ImplGlfw_InitForVulkanP10GLFWwindowb

Adding extern c to the function declaration helped:

- IMGUI_IMPL_API bool     ImGui_ImplGlfw_InitForVulkan(GLFWwindow* window, bool install_callbacks);
+ extern "C" IMGUI_IMPL_API bool     ImGui_ImplGlfw_InitForVulkan(GLFWwindow* window, bool install_callbacks);

AFTER

nm ./libimgui.a | grep InitFor
0000000000001894 T _ImGui_ImplGlfw_InitForVulkan

renderer-run
└─ run exe renderer
   └─ compile exe renderer Debug native 2 errors
error: undefined symbol: _ImGui_ImplVulkan_CreateFontsTexture
    note: referenced by /Users/akirpach/dev/repos/pdf/.zig-cache/o/0e97598755a24b84383fb7dbe87270b8/renderer_zcu.o:_backend_vulkan.init
error: undefined symbol: _ImGui_ImplVulkan_Init
    note: referenced by /Users/akirpach/dev/repos/pdf/.zig-cache/o/0e97598755a24b84383fb7dbe87270b8/renderer_zcu.o:_backend_vulkan.init

Note that the error for ImGui_ImplGlfw_InitForVulkan is gone now.

[tonitch]

It's supposed to be in the Imgui_impl_api tho
This is a lot of changes but you could try using my cimgui branch which defines this if I remember correctly

[zxubian]

@tonitch , thanks!

I tried your branch, but unfortunately the _ImGui_ImplVulkan_CreateFontsTexture is still not found.

renderer-run
└─ install renderer
   └─ compile exe renderer Debug native 1 errors
error: undefined symbol: _ImGui_ImplVulkan_CreateFontsTexture

It seems that cimgui just doesn't expose it....
https://github.com/cimgui/cimgui/blob/207fca2d361179c349f3c9d1893b8274f4bbfebf/cimgui_impl.h#L208

[zxubian]

I've made an in issue in cimgui repo:
cimgui/cimgui#304