Hello, I have an issue with ocamlbuild. I type : ocamlbuild -use-ocamlfind sdit.native I get the following error : ocamlfind: Error from package `postgresql': This library requires multi-threading support Command exited with code 2. I have checked this : $ ocamlbuild -documentation | grep thread flag {. byte, link, ocaml, program, thread .} "threads.cma -thread" flag {. link, native, ocaml, program, thread .} "threads.cmxa -thread" flag {. doc, ocaml, thread .} "-I +threads" flag {. compile, ocaml, thread .} "-thread" I have checked _build/_log also : tag thread is active # Target: sdit.native, tags: { dont_link_with, extension:native, file:sdit.native, link, native, ocaml, package(extlib), package(gsl), package(postgresql), package(pxp), package(str), program, quiet, thread, traverse, use_menhir } /usr/bin/ocamlfind ocamlopt -linkpkg -package extlib -package gsl -package postgresql -package pxp -package str dependent.cmx sdit.cmx -o sdit.native I think there is a bug with -use-ocamlfind where -thread is not appended to the command. I use ocaml 3.12.0 What do you think ? Thanks, RĂ©mi