[Caml-list] Can't build a target with C stubs using ocamlbuild

[Caml-list] Can't build a target with C stubs using ocamlbuild

[Christiano F. Haesbaert]

Hi there,

I can't seem to be able to use a C stub in my project, I was following this:

http://l-lang.blogspot.de/2012/08/incorporating-c-code-in-ocaml-project.html

After I've failed to follow the original documentation, if this is not
the correct list for such inquiries please inform me the correct one

I'm using OS X 10.10 with opam and compiler 4.02.1 from opam.

These are the contents of the files and the attempt at building it,
they can also be found at http://haesbaert.org/toto.tar.gz

### toto_c.c ###
#include <stdio.h>
void
toto(void)
{
printf("Hello from C\n");
}

### toto_c.ml ###
external toto_a: unit -> unit = "toto";;
let toto_b () = toto_a(); toto_a();;

### main.ml ###
Toto_c.toto_a();;
Toto_c.toto_b();;

## build.sh ##
#!/bin/sh

ocamlbuild -classic-display toto_c.o

ocamlbuild -classic-display -lflags toto_c.o main.native

### building... ###
/Users/haesbaert/.opam/4.02.1/bin/ocamldep.opt -modules toto_c.ml >
toto_c.ml.depends
/Users/haesbaert/.opam/4.02.1/bin/ocamlc.opt -c -o toto_c.cmo toto_c.ml
/Users/haesbaert/.opam/4.02.1/bin/ocamlopt.opt -c -o toto_c.cmx toto_c.ml
/Users/haesbaert/.opam/4.02.1/bin/ocamldep.opt -modules main.ml >
main.ml.depends
/Users/haesbaert/.opam/4.02.1/bin/ocamlc.opt -c -o main.cmo main.ml
/Users/haesbaert/.opam/4.02.1/bin/ocamlopt.opt -c -o main.cmx main.ml
/Users/haesbaert/.opam/4.02.1/bin/ocamlopt.opt toto_c.o toto_c.cmx
main.cmx -o main.native
+ /Users/haesbaert/.opam/4.02.1/bin/ocamlopt.opt toto_c.o toto_c.cmx
main.cmx -o main.native
Undefined symbols for architecture x86_64:
  "_toto", referenced from:
      .L100 in main.o
      .L100 in toto_c.o
      .L101 in toto_c.o
      _camlToto_c__1 in toto_c.o
      .L100 in toto_c.o
      .L101 in toto_c.o
      _camlToto_c__1 in toto_c.o
      ...
     (maybe you meant: _camlToto_c__toto_b_1009)
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.

Re: [Caml-list] Can't build a target with C stubs using ocamlbuild

[Jeremy Yallop]

On 5 June 2015 at 11:29, Christiano F. Haesbaert
<haesbaert@haesbaert.org> wrote:
> ### toto_c.c ###
> ### toto_c.ml ###

Both of these files will be compiled to object files called
'toto_c.o'.  Renaming one of them (e.g. toto_c.c to toto_c_stubs.c)
should fix the problem.

Re: [Caml-list] Can't build a target with C stubs using ocamlbuild

[Christiano F. Haesbaert]

On 5 June 2015 at 12:38, Jeremy Yallop <yallop@gmail.com> wrote:
> On 5 June 2015 at 11:29, Christiano F. Haesbaert
> <haesbaert@haesbaert.org> wrote:
>> ### toto_c.c ###
>> ### toto_c.ml ###
>
> Both of these files will be compiled to object files called
> 'toto_c.o'.  Renaming one of them (e.g. toto_c.c to toto_c_stubs.c)
> should fix the problem.

Hooray, great, that did the trick, thanks a lot :D.

Re: [Caml-list] Can't build a target with C stubs using ocamlbuild

[Christiano F. Haesbaert]

Just one more question, now with the real code, I was able to move
everything to myocamlbuild, but I'm getting a warning:
File "_tags", line 10, characters 12-28:
Warning: the tag "linkdep(stubs.o)" is not used in any flag
declaration, so it will have no effect; it may be a typo. Otherwise
use `mark_tag_used` in your myocamlbuild.ml to disable this warning.

## build.sh ##
ocamlbuild -use-ocamlfind all.otarget $@

## _tags line ##
<*.native>: linkdep(stubs.o)

## myocamlbuild.ml ##
open Ocamlbuild_plugin;;
dispatch begin function
  | After_rules ->
    pflag ["ocaml";"compile";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
    pflag ["ocaml";"ocamldep";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
    pdep ["link"] "linkdep" (fun param -> [param])
  | _ -> ()
end;;

It seems to be the same case as
http://stackoverflow.com/questions/25585813/mark-tag-used-warning-with-ocaml-4-02-0

Should I just use mark_tag_used ? It seems something else is wrong
since the tag is actually used.


On 5 June 2015 at 12:47, Christiano F. Haesbaert
<haesbaert@haesbaert.org> wrote:
> On 5 June 2015 at 12:38, Jeremy Yallop <yallop@gmail.com> wrote:
>> On 5 June 2015 at 11:29, Christiano F. Haesbaert
>> <haesbaert@haesbaert.org> wrote:
>>> ### toto_c.c ###
>>> ### toto_c.ml ###
>>
>> Both of these files will be compiled to object files called
>> 'toto_c.o'.  Renaming one of them (e.g. toto_c.c to toto_c_stubs.c)
>> should fix the problem.
>
> Hooray, great, that did the trick, thanks a lot :D.

Re: [Caml-list] Can't build a target with C stubs using ocamlbuild

[Gabriel Scherer]

This seems to be an ocamlbuild bug that should be reported on the bugtracker:
  http://caml.inria.fr/mantis/

On Fri, Jun 5, 2015 at 3:55 PM, Christiano F. Haesbaert
<haesbaert@haesbaert.org> wrote:
> Just one more question, now with the real code, I was able to move
> everything to myocamlbuild, but I'm getting a warning:
> File "_tags", line 10, characters 12-28:
> Warning: the tag "linkdep(stubs.o)" is not used in any flag
> declaration, so it will have no effect; it may be a typo. Otherwise
> use `mark_tag_used` in your myocamlbuild.ml to disable this warning.
>
> ## build.sh ##
> ocamlbuild -use-ocamlfind all.otarget $@
>
> ## _tags line ##
> <*.native>: linkdep(stubs.o)
>
> ## myocamlbuild.ml ##
> open Ocamlbuild_plugin;;
> dispatch begin function
>   | After_rules ->
>     pflag ["ocaml";"compile";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>     pflag ["ocaml";"ocamldep";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>     pdep ["link"] "linkdep" (fun param -> [param])
>   | _ -> ()
> end;;
>
> It seems to be the same case as
> http://stackoverflow.com/questions/25585813/mark-tag-used-warning-with-ocaml-4-02-0
>
> Should I just use mark_tag_used ? It seems something else is wrong
> since the tag is actually used.
>
>
> On 5 June 2015 at 12:47, Christiano F. Haesbaert
> <haesbaert@haesbaert.org> wrote:
>> On 5 June 2015 at 12:38, Jeremy Yallop <yallop@gmail.com> wrote:
>>> On 5 June 2015 at 11:29, Christiano F. Haesbaert
>>> <haesbaert@haesbaert.org> wrote:
>>>> ### toto_c.c ###
>>>> ### toto_c.ml ###
>>>
>>> Both of these files will be compiled to object files called
>>> 'toto_c.o'.  Renaming one of them (e.g. toto_c.c to toto_c_stubs.c)
>>> should fix the problem.
>>
>> Hooray, great, that did the trick, thanks a lot :D.
>
> --
> Caml-list mailing list.  Subscription management and archives:
> https://sympa.inria.fr/sympa/arc/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs

Re: [Caml-list] Can't build a target with C stubs using ocamlbuild

[Gabriel Scherer]

I reported and proposed a fix at
  http://caml.inria.fr/mantis/view.php?id=6893

On Fri, Jun 5, 2015 at 4:24 PM, Gabriel Scherer
<gabriel.scherer@gmail.com> wrote:
> This seems to be an ocamlbuild bug that should be reported on the bugtracker:
>   http://caml.inria.fr/mantis/
>
> On Fri, Jun 5, 2015 at 3:55 PM, Christiano F. Haesbaert
> <haesbaert@haesbaert.org> wrote:
>> Just one more question, now with the real code, I was able to move
>> everything to myocamlbuild, but I'm getting a warning:
>> File "_tags", line 10, characters 12-28:
>> Warning: the tag "linkdep(stubs.o)" is not used in any flag
>> declaration, so it will have no effect; it may be a typo. Otherwise
>> use `mark_tag_used` in your myocamlbuild.ml to disable this warning.
>>
>> ## build.sh ##
>> ocamlbuild -use-ocamlfind all.otarget $@
>>
>> ## _tags line ##
>> <*.native>: linkdep(stubs.o)
>>
>> ## myocamlbuild.ml ##
>> open Ocamlbuild_plugin;;
>> dispatch begin function
>>   | After_rules ->
>>     pflag ["ocaml";"compile";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>>     pflag ["ocaml";"ocamldep";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>>     pdep ["link"] "linkdep" (fun param -> [param])
>>   | _ -> ()
>> end;;
>>
>> It seems to be the same case as
>> http://stackoverflow.com/questions/25585813/mark-tag-used-warning-with-ocaml-4-02-0
>>
>> Should I just use mark_tag_used ? It seems something else is wrong
>> since the tag is actually used.
>>
>>
>> On 5 June 2015 at 12:47, Christiano F. Haesbaert
>> <haesbaert@haesbaert.org> wrote:
>>> On 5 June 2015 at 12:38, Jeremy Yallop <yallop@gmail.com> wrote:
>>>> On 5 June 2015 at 11:29, Christiano F. Haesbaert
>>>> <haesbaert@haesbaert.org> wrote:
>>>>> ### toto_c.c ###
>>>>> ### toto_c.ml ###
>>>>
>>>> Both of these files will be compiled to object files called
>>>> 'toto_c.o'.  Renaming one of them (e.g. toto_c.c to toto_c_stubs.c)
>>>> should fix the problem.
>>>
>>> Hooray, great, that did the trick, thanks a lot :D.
>>
>> --
>> Caml-list mailing list.  Subscription management and archives:
>> https://sympa.inria.fr/sympa/arc/caml-list
>> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
>> Bug reports: http://caml.inria.fr/bin/caml-bugs

Re: [Caml-list] Can't build a target with C stubs using ocamlbuild

[Gabriel Scherer]

(Replying in-list as other people may be interested)

On Fri, Jun 5, 2015 at 7:09 PM, Christiano F. Haesbaert
<haesbaert@haesbaert.org> wrote:
> What is the common workflow to test such diff ?
>
> Is there a way to pin the compiler in opam ?

My personal workflow is to use my script
  https://github.com/gasche/opam-compiler-conf
which creates an opam switch from a compiler directory, using the
compiler version and git branch name to choose the switch name.

Steps are:
- install the opam-compiler-conf script in your $PATH *outside* opam
(otherwise you will need to install it in all switches, pain)
- clone the compiler somewhere (and go to the branch you want to test)
- apply the patch you want to test
- opam compiler-conf configure (instead of "./configure" as suggested by README)
- make world.opt
- opam compiler-conf install (instead of "make install" as suggested by README)

This will create a switch with the compiler you installed named, for
example, 4.02.2+local-git-4.02 (more generally
$OCAMLVER+local-git-$BRANCHNAME). You can install opam packages and
test them as in any switch.

Then, if you modify the compiler again and make world.opt again, you can use
- make install
  from the compiler directory to install the compiler without
reinstalling the OPAM packages (if the binary interface didn't change
and recompilation is not needed)
or
- opam compiler-conf reinstall
  to also recompile all the OPAM packages of the script

(Another common way to get a switch: pull-request made against
github/ocaml/ocaml automatically create a corresponding switch.)

On Fri, Jun 5, 2015 at 7:09 PM, Christiano F. Haesbaert
<haesbaert@haesbaert.org> wrote:
> Thanks, off list,
>
> What is the common workflow to test such diff ?
>
> Is there a way to pin the compiler in opam ?
>
> On 5 June 2015 at 18:47, Gabriel Scherer <gabriel.scherer@gmail.com> wrote:
>> I reported and proposed a fix at
>>   http://caml.inria.fr/mantis/view.php?id=6893
>>
>> On Fri, Jun 5, 2015 at 4:24 PM, Gabriel Scherer
>> <gabriel.scherer@gmail.com> wrote:
>>> This seems to be an ocamlbuild bug that should be reported on the bugtracker:
>>>   http://caml.inria.fr/mantis/
>>>
>>> On Fri, Jun 5, 2015 at 3:55 PM, Christiano F. Haesbaert
>>> <haesbaert@haesbaert.org> wrote:
>>>> Just one more question, now with the real code, I was able to move
>>>> everything to myocamlbuild, but I'm getting a warning:
>>>> File "_tags", line 10, characters 12-28:
>>>> Warning: the tag "linkdep(stubs.o)" is not used in any flag
>>>> declaration, so it will have no effect; it may be a typo. Otherwise
>>>> use `mark_tag_used` in your myocamlbuild.ml to disable this warning.
>>>>
>>>> ## build.sh ##
>>>> ocamlbuild -use-ocamlfind all.otarget $@
>>>>
>>>> ## _tags line ##
>>>> <*.native>: linkdep(stubs.o)
>>>>
>>>> ## myocamlbuild.ml ##
>>>> open Ocamlbuild_plugin;;
>>>> dispatch begin function
>>>>   | After_rules ->
>>>>     pflag ["ocaml";"compile";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>>>>     pflag ["ocaml";"ocamldep";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>>>>     pdep ["link"] "linkdep" (fun param -> [param])
>>>>   | _ -> ()
>>>> end;;
>>>>
>>>> It seems to be the same case as
>>>> http://stackoverflow.com/questions/25585813/mark-tag-used-warning-with-ocaml-4-02-0
>>>>
>>>> Should I just use mark_tag_used ? It seems something else is wrong
>>>> since the tag is actually used.
>>>>
>>>>
>>>> On 5 June 2015 at 12:47, Christiano F. Haesbaert
>>>> <haesbaert@haesbaert.org> wrote:
>>>>> On 5 June 2015 at 12:38, Jeremy Yallop <yallop@gmail.com> wrote:
>>>>>> On 5 June 2015 at 11:29, Christiano F. Haesbaert
>>>>>> <haesbaert@haesbaert.org> wrote:
>>>>>>> ### toto_c.c ###
>>>>>>> ### toto_c.ml ###
>>>>>>
>>>>>> Both of these files will be compiled to object files called
>>>>>> 'toto_c.o'.  Renaming one of them (e.g. toto_c.c to toto_c_stubs.c)
>>>>>> should fix the problem.
>>>>>
>>>>> Hooray, great, that did the trick, thanks a lot :D.
>>>>
>>>> --
>>>> Caml-list mailing list.  Subscription management and archives:
>>>> https://sympa.inria.fr/sympa/arc/caml-list
>>>> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
>>>> Bug reports: http://caml.inria.fr/bin/caml-bugs

Re: [Caml-list] Can't build a target with C stubs using ocamlbuild

[Christiano F. Haesbaert]

I've just test 4.02.0+trunk and can confirm it fixes the issue.

Thanks again for fixing it :D.

On 5 June 2015 at 20:36, Gabriel Scherer <gabriel.scherer@gmail.com> wrote:
> (Replying in-list as other people may be interested)
>
> On Fri, Jun 5, 2015 at 7:09 PM, Christiano F. Haesbaert
> <haesbaert@haesbaert.org> wrote:
>> What is the common workflow to test such diff ?
>>
>> Is there a way to pin the compiler in opam ?
>
> My personal workflow is to use my script
>   https://github.com/gasche/opam-compiler-conf
> which creates an opam switch from a compiler directory, using the
> compiler version and git branch name to choose the switch name.
>
> Steps are:
> - install the opam-compiler-conf script in your $PATH *outside* opam
> (otherwise you will need to install it in all switches, pain)
> - clone the compiler somewhere (and go to the branch you want to test)
> - apply the patch you want to test
> - opam compiler-conf configure (instead of "./configure" as suggested by README)
> - make world.opt
> - opam compiler-conf install (instead of "make install" as suggested by README)
>
> This will create a switch with the compiler you installed named, for
> example, 4.02.2+local-git-4.02 (more generally
> $OCAMLVER+local-git-$BRANCHNAME). You can install opam packages and
> test them as in any switch.
>
> Then, if you modify the compiler again and make world.opt again, you can use
> - make install
>   from the compiler directory to install the compiler without
> reinstalling the OPAM packages (if the binary interface didn't change
> and recompilation is not needed)
> or
> - opam compiler-conf reinstall
>   to also recompile all the OPAM packages of the script
>
> (Another common way to get a switch: pull-request made against
> github/ocaml/ocaml automatically create a corresponding switch.)
>
> On Fri, Jun 5, 2015 at 7:09 PM, Christiano F. Haesbaert
> <haesbaert@haesbaert.org> wrote:
>> Thanks, off list,
>>
>> What is the common workflow to test such diff ?
>>
>> Is there a way to pin the compiler in opam ?
>>
>> On 5 June 2015 at 18:47, Gabriel Scherer <gabriel.scherer@gmail.com> wrote:
>>> I reported and proposed a fix at
>>>   http://caml.inria.fr/mantis/view.php?id=6893
>>>
>>> On Fri, Jun 5, 2015 at 4:24 PM, Gabriel Scherer
>>> <gabriel.scherer@gmail.com> wrote:
>>>> This seems to be an ocamlbuild bug that should be reported on the bugtracker:
>>>>   http://caml.inria.fr/mantis/
>>>>
>>>> On Fri, Jun 5, 2015 at 3:55 PM, Christiano F. Haesbaert
>>>> <haesbaert@haesbaert.org> wrote:
>>>>> Just one more question, now with the real code, I was able to move
>>>>> everything to myocamlbuild, but I'm getting a warning:
>>>>> File "_tags", line 10, characters 12-28:
>>>>> Warning: the tag "linkdep(stubs.o)" is not used in any flag
>>>>> declaration, so it will have no effect; it may be a typo. Otherwise
>>>>> use `mark_tag_used` in your myocamlbuild.ml to disable this warning.
>>>>>
>>>>> ## build.sh ##
>>>>> ocamlbuild -use-ocamlfind all.otarget $@
>>>>>
>>>>> ## _tags line ##
>>>>> <*.native>: linkdep(stubs.o)
>>>>>
>>>>> ## myocamlbuild.ml ##
>>>>> open Ocamlbuild_plugin;;
>>>>> dispatch begin function
>>>>>   | After_rules ->
>>>>>     pflag ["ocaml";"compile";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>>>>>     pflag ["ocaml";"ocamldep";] "ppopt" (fun s -> S [A"-ppopt"; A s]);
>>>>>     pdep ["link"] "linkdep" (fun param -> [param])
>>>>>   | _ -> ()
>>>>> end;;
>>>>>
>>>>> It seems to be the same case as
>>>>> http://stackoverflow.com/questions/25585813/mark-tag-used-warning-with-ocaml-4-02-0
>>>>>
>>>>> Should I just use mark_tag_used ? It seems something else is wrong
>>>>> since the tag is actually used.
>>>>>
>>>>>
>>>>> On 5 June 2015 at 12:47, Christiano F. Haesbaert
>>>>> <haesbaert@haesbaert.org> wrote:
>>>>>> On 5 June 2015 at 12:38, Jeremy Yallop <yallop@gmail.com> wrote:
>>>>>>> On 5 June 2015 at 11:29, Christiano F. Haesbaert
>>>>>>> <haesbaert@haesbaert.org> wrote:
>>>>>>>> ### toto_c.c ###
>>>>>>>> ### toto_c.ml ###
>>>>>>>
>>>>>>> Both of these files will be compiled to object files called
>>>>>>> 'toto_c.o'.  Renaming one of them (e.g. toto_c.c to toto_c_stubs.c)
>>>>>>> should fix the problem.
>>>>>>
>>>>>> Hooray, great, that did the trick, thanks a lot :D.
>>>>>
>>>>> --
>>>>> Caml-list mailing list.  Subscription management and archives:
>>>>> https://sympa.inria.fr/sympa/arc/caml-list
>>>>> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
>>>>> Bug reports: http://caml.inria.fr/bin/caml-bugs