How do I link gtk to the project (pkg-config)?

[Heus-Sueh]

in the gtk compilation tutorial it uses gcc together with pkg-config, but it seems that cmkr does not support this module: https://cmake.org/cmake/help/latest/module/FindPkgConfig.html

the command would be this gcc $( pkg-config --cflags gtk4 ) -o example-0 example-0.c $( pkg-config --libs gtk4 ), how to translate this to cmkr?

[mrexodia]

Cmkr purposefully does not support pkg-config, which is not platform agnostic and encourages bad CMake practices. Instead you should do something like this:

[variables]
CMAKE_MODULE_PATH = "cmake"

# Looks for cmake/FindGTK4.cmake
[find-package.GTK4]

[target.mygui]
type = "executable"
sources = ["src/main.cpp"]
link-libraries = ["GTK4::gtk4"]

You will then need to write cmake/FindGTK4.cmake to create an IMPORTED target called GTK4::gtk4. I used ChatGPT for this because I couldn't test:

# FindGTK4.cmake - Find GTK4 package using pkg-config and create imported targets.

# Check if GTK4 is already found
if(TARGET GTK4::gtk4)
    set(GTK4_FOUND ON)
    return()
endif()

# Find the GTK4 package using pkg-config
find_package(PkgConfig REQUIRED)
pkg_check_modules(GTK4 REQUIRED gtk4)

# Create the imported target
add_library(GTK4::gtk4 INTERFACE IMPORTED)

# Set the include directories
set_target_properties(GTK4::gtk4 PROPERTIES
    INTERFACE_INCLUDE_DIRECTORIES "${GTK4_INCLUDE_DIRS}"
    INTERFACE_COMPILE_OPTIONS "${GTK4_CFLAGS_OTHER}"
    INTERFACE_LINK_LIBRARIES "${GTK4_LIBRARIES}"
)

The documentation for pkg_check_modules also has an option to created an IMPORTED target for you, so you'll have to experiment with that.

[mrexodia]

Following up, here is an example project that does this: https://github.com/mrexodia/invivo-cbct

cmake/FindJasPer.cmake:

if(TARGET JasPer::jasper)
    set(JasPer_FOUND ON)
    return()
endif()

find_package(PkgConfig REQUIRED)
pkg_check_modules(JasPer REQUIRED jasper)

add_library(JasPer::jasper INTERFACE IMPORTED)
set_target_properties(JasPer::jasper PROPERTIES
    INTERFACE_INCLUDE_DIRECTORIES "${JasPer_INCLUDE_DIRS}"
    INTERFACE_COMPILE_OPTIONS     "${JasPer_CFLAGS_OTHER}"
    INTERFACE_LINK_LIBRARIES      "${JasPer_LINK_LIBRARIES}"
)

And the relevant part of cmake.toml:

[variables]
CMAKE_MODULE_PATH = "cmake"

[project]
name = "invivo-cbct"
version = "1.0.0"
languages = ["C"]

[vcpkg]
version = "2025.06.13"
packages = ["sdl2", "jasper", "pthreads", "stb", "pkgconf"]
overlay = "vcpkg-overlay"

[find-package.SDL2]
required = true
config = true

[find-package.JasPer]
required = true

[find-package.PThreads4W]
required = true

[find-package.Stb]
required = true

Important to add pkgconf to [vcpkg].packages because otherwise you need to install it globally on Windows.