Dear Camlers, I’ve been fighting for one entire day with a problem without success and the more i dig, the more confused i am :( Suppose i define a small opam package - let’s call it « dummy » : opam-version: "2.0" name: "dummy" version: "0.0" synopsis: "A dummy OPAM package" maintainer: "JS" authors: "JS" license: "MIT" depends: [ "ocaml" "ocamlfind" ] build: [ [make] ] where [make] simply builds the library files [mylib.cma] and [mylib.cmxa] (by directly calling ocamlc/opt or using dune - this does not matter here). What is the correct way to make this package available to other programs : [opam pin add .] or [opam install .] ? I’ve tried both solutions but systematically get : ocamlfind ocamlc -package dummy -linkpkg -o main main.ml ocamlfind: Package `dummy' not found when trying to compile [main.ml], where this file contains, for example : « let _ = Mylib.dump () » (and where [dump] is a function defined in mylib.ml » When simply pinning the package, [opam info dummy] gives : <><> dummy: information on all versions <><><><><><><><><><><><><><><><><><> 🐫 name dummy all-versions 0.0 <><> Version-specific details <><><><><><><><><><><><><><><><><><><><><><><> 🐫 version 0.0 pin file:///Users/jserot/Dev/ml/opam/simple/build/raw url.src: "file:///Users/jserot/Dev/ml/opam/simple/build/raw" authors: "JS" maintainer: "JS" license: "MIT" depends: "ocaml" "ocamlfind" synopsis A dummy OPAM package which tends does not show any installed version of the package (and hence could explain why ocamlfind does not find it ?) After installing the package ([opam install .]), [opam info dummy] gives : $ opam info dummy <><> dummy: information on all versions <><><><><><><><><><><><><><><><><><> 🐫 name dummy all-installed-versions 0.0 [4.06.0] all-versions 0.0 <><> Version-specific details <><><><><><><><><><><><><><><><><><><><><><><> 🐫 version 0.0 pin file:///Users/jserot/Dev/ml/opam/simple/build/raw url.src: "file:///Users/jserot/Dev/ml/opam/simple/build/raw" authors: "JS" maintainer: "JS" license: "MIT" depends: "ocaml" "ocamlfind" synopsis A dummy OPAM package $ which now seems to indicates that the package is « installed » (though i do not fully understand the distinction between the former case..). But i still get the message ocamlfind ocamlc -package dummy -linkpkg -o main main.ml ocamlfind: Package `dummy' not found There must be sth i’m doing wrong (or have not understood in the way opam works).. Any help appreciated. Jocelyn