Chapter 35 Recently removed or moved libraries (Graphics, Bigarray, Num, LablTk)

This chapter describes three libraries which were formerly part of the OCaml distribution (Graphics, Num, and LablTk), and a library which has now become part of OCaml’s standard library, and is documented there (Bigarray).

1 The Graphics Library

Since OCaml 4.09, the graphics library is distributed as an external package. Its new home is:

If you are using the opam package manager, you should install the corresponding graphics package:

        opam install graphics

Before OCaml 4.09, this package simply ensures that the graphics library was installed by the compiler, and starting from OCaml 4.09 this package effectively provides the graphics library.

2 The Bigarray Library

As of OCaml 4.07, the bigarray library has been integrated into OCaml’s standard library.

The bigarray functionality may now be found in the standard library Bigarray module, except for the map_file function which is now part of the Unix library. The documentation has been integrated into the documentation for the standard library.

The legacy bigarray library bundled with the compiler is a compatibility library with exactly the same interface as before, i.e. with map_file included.

We strongly recommend that you port your code to use the standard library version instead, as the changes required are minimal.

If you choose to use the compatibility library, you must link your programs as follows:

        ocamlc other options bigarray.cma other files
        ocamlopt other options bigarray.cmxa other files

For interactive use of the bigarray compatibility library, do:

        ocamlmktop -o mytop bigarray.cma

or (if dynamic linking of C libraries is supported on your platform), start ocaml and type #load "bigarray.cma";;.

3 The Num Library

The num library implements integer arithmetic and rational arithmetic in arbitrary precision. It was split off the core OCaml distribution starting with the 4.06.0 release, and can now be found at

New applications that need arbitrary-precision arithmetic should use the Zarith library ( instead of the Num library, and older applications that already use Num are encouraged to switch to Zarith. Zarith delivers much better performance than Num and has a nicer API.

4 The Labltk Library and OCamlBrowser

Since OCaml version 4.02, the OCamlBrowser tool and the Labltk library are distributed separately from the OCaml compiler. The project is now hosted at