This boilerplate is a simple example of how to build a simple Objective-C 2.0 project on Linux with GNUstep, and macOS with Apple frameworks.

GNUstep

We use the GNUstep configuration tool gnustep-config to get the GNUstep and Objective-C specific compiler and linker flags.

Make sure to source the GNUstep.sh script in your shell before compiling and running the program, otherwise meson might not be able to locate gnustep-config.

If you used the standard FHS installation layout, or did not explicitly set a layout when building GNUstep, you can source the script like this:

source /usr/share/GNUstep/Makefiles/GNUstep.sh

Note that the Makefiles directory might be located in a different place on your system, depending on your distribution.

Meson also looks for CC, and OBJC environment variables to be set. Use clang as the compiler, as GCC does not support Objective-C 2.0.

Apple frameworks

On macOS, meson will automatically find the Apple frameworks. Currently, only the Foundation framework is used, but you can add more frameworks by adding them to the modules array in meson.build.

Be aware that some frameworks are not available on Linux, and you will need to use a different implementation.

Dependencies

Linux

• A working GNUstep installation with Objective-C 2.0 support (libobjc2, gnustep-make, gnustep-base). Please note that as of writing this, the GNUstep debian packages do not support Objective-C 2.0, and use the GCC runtime.

Building

First, setup the meson project and build/ directory:

# Source the GNUstep environment script if not already done by your shell configuration (e.g. source /usr/share/GNUstep/Makefiles/GNUstep.sh)
OBJC=clang meson setup build

You can now compile and execute the example program:

ninja -C build
./build/objc-boilerplate

If everything worked, you should see an output similar to this:

2023-10-16 11:28:06.806 objc-boilerplate[40560:40560] Hello, World!