I am using Jane Street's async_core by adding package(async_core) in _tags.
When I use ocamlbuild -use-ocamlfind -I src test/test_airport.native, it gives me the following error:
camlfind ocamlopt -linkpkg -package async_core -package unix -package
netclient -package mongo -package xml-light src/airport.cmx
test/test_airport.cmx -o test/test_airport.native ocamlfind: Error
from package `threads': Missing -thread or -vmthread switch
I googled it and here is what I got http://caml.inria.fr/pub/docs/manual-ocaml-4.00/manual039.html
It says:
Programs that use system threads must be linked as follows:
ocamlc -thread other options unix.cma threads.cma other files
So I changed my ocamlbuild command like this:
ocamlbuild -use-ocamlfind -cflag -thread -I src test/test_airport.native
But the error remains the same. also the actual command that ocamlbuild generated remains the same without -thread.
How can I deal with this?
What you want to know is whether there is an ocamlbuild tag (~ feature) to add the -thread argument to the relevant command-lines, instead of hacking it with -cflag in unsatisfying ways. As explained in this blog post, you should use the -documentation option of ocamlbuild:
% 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"
So the answer is: add -tag thread to your ocamlbuild invocation
line, or just thread in the relevant place in _tags.
Related
I have simple program, which uses function from Core.Std module, e.g.:
open Core.Std
let _ = List.last [1;2;3]
I can compile and link it by ocamlfind or ocamlbuild:
ocamlfind ocamlc -package core -linkpkg -thread app.ml
ocamlbuild -use-ocamlfind -pkgs core -tag thread app.native
But I don't know how to compile and link such file using "normal" OCaml compiler:
ocamlc -c -I ~/.opam/system/lib/core_kernel/ -I ~/.opam/system/lib/core/ app.ml
ocamlc ~/.opam/system/lib/core_kernel/core_kernel.cma ~/.opam/system/lib/core/core.cma app.cmo
Last of above commands gives the following error:
File "_none_", line 1:
Error: Error on dynamically loaded library: /home/maciej/.opam/system/lib/stublibs/dllcore_kernel_stubs.so: /home/maciej/.opam/system/lib/stublibs/dllcore_kernel_stubs.so: undefined symbol: caml_ba_alloc
What am I doing wrong?
You can use ocamlfind ocamlc -only-show … to see the full command constructed by ocamlfind . Your error points towards some missing transitive dependencies of Core and an old version of OCaml and Core.
I'm somehow trying to use _CoqProject parser from coq's library in OCaml (I'd welcome better alternatives to grab the .v files of a coq project if that library is not meant for external use, is it?), but ocamlbuild seems to be linking libraries in the wrong order.
Consider this minimal example file
open CoqProject_file
let x = read_project_file
The coq.lib package (bundled with coq) somehow depends on threads, and following this answer suggests to use -tag thread for that, but I still get the following error that threads is not found when linking coq.lib:
$ ocamlbuild -pkg coq.lib -tag thread -cflag -rectypes a.native /tmp/p
+ /home/sam/.opam/4.06.0+coq-8.7/bin/ocamlopt.opt -I /home/sam/.opam/4.06.0+coq-8.7/lib/coq/config -I /home/sam/.opam/4.06.0+coq-8.7/lib/coq/lib -I /home/sam/.opam/4.06.0+coq-8.7/lib/ocaml /home/sam/.opam/4.06.0+coq-8.7/lib/ocaml/str.cmxa /home/sam/.opam/4.06.0+coq-8.7/lib/ocaml/unix.cmxa /home/sam/.opam/4.06.0+coq-8.7/lib/coq/lib/clib.cmxa -thread threads.cmxa a.cmx -o a.native
File "_none_", line 1:
Error: No implementations provided for the following modules:
Thread referenced from /home/sam/.opam/4.06.0+coq-8.7/lib/coq/lib/clib.cmxa(Exninfo)
Mutex referenced from /home/sam/.opam/4.06.0+coq-8.7/lib/coq/lib/clib.cmxa(Exninfo)
Command exited with code 2.
Yet that compiles if I take the ocamlopt invocation apart and put -thread threads.cmxa before clib.cmxa
$ cd _build/
$ /home/sam/.opam/4.06.0+coq-8.7/bin/ocamlopt.opt -I /home/sam/.opam/4.06.0+coq-8.7/lib/coq/config -I /home/sam/.opam/4.06.0+coq-8.7/lib/coq/lib -I /home/sam/.opam/4.06.0+coq-8.7/lib/ocaml /home/sam/.opam/4.06.0+coq-8.7/lib/ocaml/str.cmxa /home/sam/.opam/4.06.0+coq-8.7/lib/ocaml/unix.cmxa -thread threads.cmxa /home/sam/.opam/4.06.0+coq-8.7/lib/coq/lib/clib.cmxa a.cmx -o a.native
What is the right way to call ocamlbuild?
If you use ocamlfind packages, you should use the -use-ocamlfind flag.
There is no good solution as to why -tag thread is needed¹. There are two different implementations of the OCaml Threads interface (one with os threads and one with green threads), and coq.lib depends on the interface but won't decide for the user which one to use, so you have to specify it manually, for example by using -tag thread.
¹: one solution would be to remove this choice by deprecating vmthreads (the green threads), which is rarely used in practice.
I have a three signatures A.mli,B.mli,and C.mli. Within them I have submodules Aa, Bb, and Cc respectively and also a signature for the implementations Ai, Bi, and Ci.
I have implemented them in a file called D.ml which looks like this
open A
open B
open C
module Ai : Aa = struct ... end
module Bi : Bb = struct ... end
module Ci : Cc = struct ... end
I compile them each in turn with the following commands:
ocamlfind ocamlc -linkpkg -thread -package core A.mli
ocamlfind ocamlc -linkpkg -thread -package core B.mli
ocamlfind ocamlc -linkpkg -thread -package core C.mli
ocamlfind ocamlc -linkpkg -thread -package core D.ml
which all succeed.
I then have a file E.ml where I try to use the modules Ai, Bi, Ci.
open A
open B
open C
module M = Ai(Ci)
(* do something else *)
However when I try to compile E.ml I get the
Error: Error while linking E.cmo:
Reference to undefined global `A`
I think I have to somehow include D.ml in the compilation step but I'm unsure how to.
Using ocamlc or ocamlopt compiler directly (even with the help of ocamlfind) is not an easy task, and should be left only for those, who write OCaml tools and very sure in what they're doing. So, in short, just use ocamlbuild, that is the default way of compiling things in OCaml world. Since, you're using Core library it would be also a good idea to use corebuild instead of ocamlbuild. corebuild is shipped with core, and is actually a small wrapper around ocamlbuild, that adds core dependencies, as well as some handy flags. So, with corebuild you can compile just with:
corebuild E.native
Without corebuild, you can compile with
ocamlbuild -pkg core E.native
ocamlbuild will do all the work for you, i.e., find all dependencies, sort them in correct order, invoke proper tools, etc... You just need this one, command.
If you're still interested in how to compile your example project properly, then you can ask ocamlbuild about this. Use -classic-display option, that will show you all intermediate commands,
ocamlbuild -use-ocamlfind -classic-display -pkg core E.byte
Will show you all steps. (You may need to ocamlbuild -clean, so that you can see all the steps from the start).
Just beginning with ocaml and am struggling with the various compilers and tooling. E.g. ocamlopt, ocamlc, ocamlbuild, corebuild and so on. So, how do I compile the following?
open Core.Std
module Regex = Re2.Regex
let ls pattern =
let pat = Regex.create_exn pattern in
let matcher = Regex.matches pat in
Sys.ls_dir "."
|> List.filter ~f:matcher
|> List.iter ~f:(fun s -> print_string s; print_newline ())
let () =
match In_channel.input_line stdin with
| None -> print_string "No Input"
| Some pat -> ls pat
In utop I can just #require "re2" and go from there.
Without the inclusion of the regular expressions module I would just use corebuild ls.native, assuming that the above code is placed into ls.ml.
[edit]
Have so far tried
ocamlbuild -use-ocamlfind -package core -package re2
which spit out
ocamlfind ocamldep -package core -package re2 -modules ls.ml > ls.ml.depends
ocamlfind ocamlc -c -package core -package re2 -o ls.cmo ls.ml
+ ocamlfind ocamlc -c -package core -package re2 -o ls.cmo ls.ml
ocamlfind: Error from package `threads': Missing -thread or -vmthread switch
Command exited with code 2.
So after some googling I was led to this blog I tried
ocamlbuild -tag thread -use-ocamlfind -package core -package re2
which spits out over 6000 lines of what looks like make output before failing with:
collect2: error: ld returned 1 exit status
File "caml_startup", line 1:
Error: Error during linking
Command exited with code 2.
so I'm not sure what to try next.
I am using Ubuntu 14.04 on a 64bit machine. I ditched the apt-get versions of ocaml:
sudo apt-get remove --purge ocaml ocaml-base-nox ocaml-compiler-libs \
ocaml-interp ocaml-native-compilers \
ocaml-nox campl4 ocaml-base ocaml-docs opam
Then I installed opam from source according to the instructions here.
Next I installed core, utop, and re2 with opam install core utop re2
And finally I ran ocamlbuild -use-ocamlfind -package re2 -package core -tag thread ls.native
which built the desired executable.
I would suggest you to use oasis tool. It is not as hard, as one may think. But it removes all library burden from you.
Lets create a simple _oasis file for your project:
OASISFormat: 0.4
Name: ls
Version: 0.1
Synopsis: Testing oasis
Authors: Fizz_ed
License: MIT
Plugins: META (0.4), DevFiles (0.4)
BuildTools: ocamlbuild, camlp4o
BuildDepends: core, camlp4, threads,
sexplib.syntax,
bin_prot.syntax,
comparelib.syntax,
herelib,
herelib.syntax
Executable "ls"
Path: .
MainIs: ls.ml
CompiledObject: best
BuildDepends: re2
After you've created this file, run oasis setup command (if oasis is not installed, then install it using opam, or your package manager).
After that you will have a common configure script and makefiles. So all you need is to type
./configure
make
and your file will be compiled.
Or you can just use ocamlbuild directly, it will work too, since oasis created all the necessary files
ocamlbuild ls.native
A few explanations about the file. The preamle contains everything you need to build your core-style applications.
Executable section describes your executable file, and also adds a dependency to re2 library.
Update: fixed some issues.
I am currently working on a website project written in OCaml and compiled to javascript using js_of_ocaml. It works pretty well as long as I have only one source file using the command ocamlfind ocamlc -package js_of_ocaml -package js_of_ocaml.syntax -syntax camlp4o -linkpkg -o file.byte file.ml but I would like to include several modules in my project. How can I do that ?
The other modules are actually a lexer and a parser poduced by ocamllex and menhir. I have read a tutorial on how to use ocamllex and menhir with js_of_ocaml but it makes wrong assumptions on where js_of_ocaml is installed (I installed it with opam) and it uses ocamlbuild and I want to know how to do it by hand without using an automated tool such as ocamlbuild.
I found the solution by trying to understand the makefiles for the official examples.
Here is my Makefile :
OBJS=file1.cmo file2.cmo file3.cmo
NAME=projectname
OCAMLC=ocamlfind ocamlc -package js_of_ocaml -package js_of_ocaml.syntax -syntax camlp4o
$(NAME).byte: $(OBJS)
$(OCAMLC) -linkpkg -o $# $(OBJS)
$(NAME).js: $(NAME).byte
js_of_ocaml $<
%.cmo: %.ml
$(OCAMLC) -c $<
...
ocamlbuild keeps a log of the operations it performs. After an ocamlbuild call, look at _build/_log and you will see all the commands that it has invoked, with full arguments etc. That's probably the easiest way for you to figure how to do it by hand.
(Regarding +site-lib assumptions and OPAM, that's something you should report to the authors of the tutorial, they'll want to make sure that it also works for OPAM users.)
It's taken a bunch of experimentation, but I finally figured out how to have ocamlbuild pass the same flags to ocamlfind as ocsigen use in those makefiles. I'm also using js_of_ocaml installed with OPAM.
For my test case, I created a very small example with two files - main.ml and square.ml.
square.ml:
let square x = x * x
main.ml:
let () = (Js.Unsafe.coerce Dom_html.window)##square <- Js.wrap_callback Square.square
The command to build this successfully:
ocamlbuild -use-ocamlfind -pkgs js_of_ocaml,js_of_ocaml.syntax -syntax camlp4o main.byte
This produces identical JS output to my initial test case where the square function was in main.ml. The ocamlbuild log shows exactly what I expect (two calls to ocamldep, two to ocamlc -c, one to ocamlc -linkpkg).