Hi everybody! :wave: Can anybody help me to figure out why this can happen on OS X (arm64)? I have a very simple code let hello () = Lwt_main.run (Lwt_io.printl "Hello, world!") which compiles, but doesn’t link % ocamlfind opt -output-complete-obj -thread -package lwt.unix -linkpkg -o lib.o lib…

I get the same with linux with x86_64, so it is not to do with OS X specifically. Nor is it anything specific to lwt.unix: I seem to get the error with any attempt to combine the --output-complete-obj flag with ocamlfind’s -linkpkg. I also seem to get the same problem if I use dune instead of ocam…

Thank you @cvine for experimenting! What you’ve proposed works fine for me. I just put a snippet for history. LIB=`ocamlc -where` libtool -static -o libexport.a \ ${LIB}/libasmrun.a \ ${LIB}/libunix.a \ ${LIB}/libthreadsnat.a \ ${LIB}/../lwt/unix/liblwt_unix_stubs.a \ lib.o

Two things: first you can find the location of liblwt_unix_stubs.a with `ocamlfind query lwt.unix`, which might simplify your Makefile. Secondly further experimentation shows that using the -output-complete-obj compiler flag with ocamlfind’s -thread and -linkpkg options will fail at link time where…

It seems that in the failing case ocamlopt calls ld with -lpthread, whereas by default (when linking an executable or shared object) it calls gcc with -lpthread and -pthread. In fact it looks like the problem seems to come from the use of ld -r vs regular ld, perhaps pthread is handled specially. -…

I found the bug report (closed due to inactivity): ld: warning: /usr/lib/libpthread.dylib, ignoring unexpected dylib file · Issue #7933 · ocaml/ocaml · GitHub The issue is relevant to me in the context of an iOS project using opam-cross-ios where the main program is in C. I am building the OCaml li…

[image] cvine: I can work around the problem on a toy example by using the --output-obj flag instead and linking libunix.a, libthreadsnat.a, libasmrun.a and liblwt_unix_stubs.a into the final executable by hand. @cvine Do you have a working dune file for your workaround that you can share? Wh…

No, I couldn’t get dune to work with ocaml’s -output-obj flag but I didn’t spend much time trying. Since the C part of the program used Makefiles (generated by autoconf) I just used a Makefile for the ocaml code also, which called up ocamlopt via ocamlfind to generate a library archive. The linkin…

For the record, this works for me without error: (executable (name lib) (libraries threads) (flags (:standard -noautolink -cclib -lunix -cclib -lthreadsnat)) (foreign_stubs (language c) (names libwrap)) (modes (native object)))

`pthread` is missing on OS X

Learning

borisd September 25, 2022, 3:03am 5

I am running into the same issue. Is this a bug in ocamlfind or ocaml? Do you know if a bug report has been filed?

Topic		Replies	Views
Ocamlfind can't find threads.cmxa after adding `-package threads` Learning build	10	950	March 28, 2024
Js_of_ocaml / Lwt: Missing Ocaml threads primitives at compilation Community lwt , js_of_ocaml	7	1436	July 31, 2020
How to compile OCaml and C/C++ code that depend on each other? Learning dune	21	2972	May 8, 2020
Linker errors when using the `threads` library and building an object file (.o) Ecosystem build , dune	9	1931	February 2, 2024
Can't link complete object file in a C program Learning dune , linking	1	1201	August 2, 2018

`pthread` is missing on OS X

Related topics