backtracking/mlpost

Linking problem with the opam `mlpost` package

Opened this issue · 5 comments

jonathan-laurent commented

I have just installed mlpost using opam (ocaml version: 4.04.2) and attempted to compile the following trivial program using ocamlbuild:

open Mlpost
open Command
open Box

let fig = draw (rect (tex "F"))

let () = 
    Metapost.emit "fig" fig ;
    Metapost.dump ~pdf:true "tmp"

I got the following linking error:

ocamlbuild -use-ocamlfind main.native
+ ocamlfind ocamlopt -linkpkg -package mlpost main.cmx -o main.native
Undefined symbols for architecture x86_64:
  "_ml_FT_Get_Char_Index", referenced from:
      _camlMlpost__Fonts__fun_2589 in mlpost.a(mlpost.o)
      _camlMlpost__Fonts__fun_2583 in mlpost.a(mlpost.o)
      _camlMlpost__Mlpost_ft__3 in mlpost.a(mlpost.o)
  "_ml_FT_Get_Name_Index", referenced from:
      _camlMlpost__Fonts__compute_trans_enc_1967 in mlpost.a(mlpost.o)
      _camlMlpost__Mlpost_ft__3 in mlpost.a(mlpost.o)
  "_ml_FT_num_charmaps", referenced from:
      _camlMlpost__Mlpost_ft__ft_set_charmap_1220 in mlpost.a(mlpost.o)
      _camlMlpost__Mlpost_ft__3 in mlpost.a(mlpost.o)
  "_ml_FT_set_charmap", referenced from:
      _camlMlpost__Mlpost_ft__ft_set_charmap_1220 in mlpost.a(mlpost.o)
      _camlMlpost__Mlpost_ft__3 in mlpost.a(mlpost.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
File "caml_startup", line 1:
Error: Error during linking
Command exited with code 2.

Besides, if I run the mlpost command line program on my source file, I get this other linking error:

File "main.ml", line 1:
Error: Error on dynamically loaded library: /Users/jlauren1/.opam/latest/lib/stublibs/dllmlpost_ft.so: dlopen(/Users/jlauren1/.opam/late
st/lib/stublibs/dllmlpost_ft.so, 138): Symbol not found: _caml_curry2
  Referenced from: /Users/jlauren1/.opam/latest/lib/stublibs/dllmlpost_ft.so
  Expected in: flat namespace
 in /Users/jlauren1/.opam/latest/lib/stublibs/dllmlpost_ft.so

I am a Mac user if this helps.

backtracking commented
ppedrot commented

I have the same issue with OCaml 4.04.0+fp on a Debian unstable, trying to install melt either with opam or by hand. The particular missing function in my case is ml_FT_num_charmaps, and it definitely seems to be a C function which is part of the MLpost distribution...

ppedrot commented

There is something wrong with the MLpost opam package it seems. If I compile and install it by hand, using the very same commands that are written in the opam script, the dllmlpost_ft.so library does contain the missing function ml_FT_num_charmaps. If I install it through opam, there are a few symbols that are marked as unavailable, according to nm (U), while they were T with hand installation.

Something very strange is going on... The only difference I can see between both cases is the path where the commands are performed.

reubenrowe commented

I have had the same problem installing melt, with 4.04.0, on Ubuntu 16.04. I tried compiling and installing mlpost manually as described by @ppedrot. First of all, I downloaded the source from the link given in OPAM:

http://mlpost.lri.fr/download/mlpost-0.8.2.tar.gz

But I still encountered the linking error when trying to install melt.

Then I downloaded the source from @backtracking's github:

https://github.com/backtracking/mlpost/releases/tag/0.8.2

and after compiling and installing from this source, my install of melt succeeded.

One difference I can see between the two source trees is that the latter contains the .c files

backend/ml_mlpost_ft.c
backend/libmlpost_ft.clib

while the former does not.

Could this be the source of the problem?

ppedrot commented

@reubenrowe I'd bet it is, because these are precisely the files that define the missing symbols!