Building portable OCaml bytecode embedded in a C project

This repository illustrates how to create a portable C package from OCaml source code. The OCaml code used was taken directly from the book Real World OCaml with a minor addition to add some IO (which necessitates inclusion of the unix library). My only contribution here was to extract the OCaml bytecode runtime and unix library, which is ~6 MB from the OCaml compiler source and create the required Makefiles. I did this to make things as simple to follow as possible while demonstrating how you would go about doing this in practice. Hopefully others will find this useful.

Requirements

The OCaml runtime and unix library is from OCaml version 4.14.0 and so you need to have this version of the compiler on your system and a C compiler. If you are using windows you will need MinGW, Cygwin or some other tool that provides a POSIX API.

Building

Generate the C package by changing into the repo directory and running make:

$ cd ocaml_c_pkg
$ make

this will create a subdirectory called pkg/ with the generated C code, main.c, OCaml bytecode runtime source and Makefile. To build the package:

$ cd pkg
$ make

If the build fails it likely means that the OCaml bytecode runtime isn't supported on your particular platform. In theory this should work on any system with a functioning C compiler.

License

I've used the same license as the authors of Real World OCaml. Of course the OCaml bytecode runtime taken from the OCaml compiler is under its own license (LGPL 2.1) and a copy is included.