ocamlsdl on MacOS X 10.5 "Leopard"

I've found that there a number of pitfalls that make getting ocamlsdl up and running on Leopard a less than straightforward experience. For the record, here are a number of fixes I found I needed to apply. I'm reconstructing the process after the fact, so I apologize if anything is missing.

0. Prepare your environment

You'll need to set up some environment variables first. I'm a tcsh user, while the default in Leopard is bash; hence, you'll have to modify the environment yourself depending on your shell.

Include X11 in your executable path
libpng and freetype2 live inside /usr/X11. The standard way to pass linker options is to use libpng-config and freetype-config, these are in /usr/X11/bin. Add this to your binary path.
Fix broken Leopard linker
Set and export LDFLAGS with value
-dylib_file \

(this is one long option, broken into lines for ease of reading.)

1. Get SDL to compile

SDL proper builds and installs without problems; however, the tests need manual intervention.

  1. Enter the test directory and ./configure.
  2. Then manually edit Makefile and append $(LDFLAGS) to CFLAGS (line 7).
  3. Finally make and run the tests. A good test to try is testwm.

2. Compile attendant libraries

For some strange reason, SDL_image won't find the built-in libpng. Build and install it, together with libtiff. Then, build and install SDL_image, SDL_ttf and SDL_mixer. Everything should work; if not, check that the variables above are correctly set in your session's environment.

3. Compile ocamlsdl

I assume you're using ocamlfind; if not, you'll probably not find trouble with the last step.

  1. Start by doing ./configure; it should say that it'll build SDL_image, SDL_ttf and SDL_mixer.
  2. Then, edit makefile.config.gcc so that lines 29 and 30 read -framework Cocoa instead of the original -Wl,-framework,Cocoa.
  3. Also, edit src/Makefile so that line 89 reads $(RANLIB) $$($(OCAMLFIND) query sdl)/*.$(A) instead of the original $(RANLIB) $$($(OCAMLFIND) printconf destdir)/*.$(A).
  4. Finaly make it.

If you've installed a previous version of ocamlsdl and you're using ocamlfind, you'll need to manually remove the installation directory (ocamlfind query sdl) prior to sudo make install.

3. Test ocamlsdl

I've found a great "hello world"-type of walk-through., but it needs some tweaking for MacOS X, as the ocamlsdl README explains. Use the following Makefile:

RESULT        = testsdl_1
SOURCES       = testsdl_1.ml
PACKS         = bigarray sdl

include OCamlMakefile

and make sure that the example built with make nc (native code) and make (bytecode) both work. Again, I assume you're using ocamlfind.

Good luck!


efnx said...

I've followed all the steps and I'm sure my installations are correct, but it looks as if there's something wrong with OCamlMakefile. Here's the error that I'm getting:

make[1]: *** No rule to make target `testsdl_1.cmi', needed by `testsdl_1'. Stop.
make: *** [byte-code] Error 2

I'll admit I'm not familiar with ocamlc and ocamlopt, maybe using OCamlMakefile for this is a little overkill?

efnx said...

My problem was my ocamlsdl installation, I had installed ocamlsdl before installing ocamlfind. I hadn't followed the steps quite like I said I had.