ocamlbuild; building toplevel

Question

Having successfully reorganized my project for ocamlbuild with subdirectories and using ocamlfind, I've found it difficult to build the top-level.

I've constructed a .mltop file containing all the modules that would be included and added the packages to the _tags, but the build doesn't work. It cannot find the C functions that are compiled with one of the modules. With -classic-display on, I can see that file, libcside.a, not being included and isn't even being compiled at all! The c file is added as a dependency in myocamlbuild.ml by,

flag ["link"; "ocaml"; "use_cutil"] (S [A"-cclib"; A"-L."; ]);
dep  ["link"; "ocaml"; "use_cutil"] ["libcside.a"];

and in _tags,

<utilities.*> : use_cutil
<**/*.top> : use_str, use_unix, use_cutil, use_curl, use_mysql

and, finally, in libcside.clib,

cutil.o

I'm missing something in setting up the build for the top level, but I cannot find a reliable resource online. Thanks.

Answer 1

• I presume that cutil.ml describes ocaml side of libcside.a - correct?
• Did you put Cutil in mltop?
• With your current plugin cutil ocaml library will not link libcside.a in (dep only instructs ocamlbuild to build it, not link)

• Here is a simple (and working) way to build project-local ocaml library with C stubs. In myocamlbuild.ml:

  ocaml_lib "linuxnet";
  let liblinuxnet_stubs = "liblinuxnet_stubs." ^ !Options.ext_lib in
  flag ["link"; "ocaml"; "use_linuxnet"] (S[A"-cclib"; A liblinuxnet_stubs;]);
  dep  ["link"; "ocaml"; "use_linuxnet"] [liblinuxnet_stubs];
  

  In liblinuxnet_stubs.clib:

  linuxnet_c.o
  

  Notice that the C source is called linuxnet_c.c so that the resulting object file doesn't override the one from linuxnet.ml (or vice versa). And finally in _tags:

  true: use_linuxnet
  

  With this setup it will be available in toplevel (note that there is no need to put Linuxnet into .mltop cause linuxnet.cma will be added to link by use_linuxnet flag (generated with ocaml_lib usage)).