glibc and ocaml/libasmrun.a

glibc and ocaml/libasmrun.a

[Radu Grigore]

Hello,

I have trouble distributing a self contained executable.

Two users reported "collect_events: /lib/i686/libc.so.6: version
`GLIBC_2.3' not found". I do not have any control over their system,
so I tried to link statically against glibc by using:

  ocamlopt -ccopt -static collect_events.ml

I get:

  /usr/local/lib/ocaml/libasmrun.a(unix.o)(.text+0x241): In function
`caml_dlopen':
  warning: Using 'dlopen' in statically linked applications requires
at runtime the shared libraries from the glibc version used for
linking

At first I thought that my program uses a library function whose
implementation explicitly tries to load dynamically. But the same
warning is obtained if collect_events.ml is an empty file. It looks
like the interpreter itself wants to link dynamically against glibc.
Is this a correct diagnostic? Is there a way around it?

Other info: 
  ocaml version 3.08.1
  my system: Fedora Core 1
  user system: (probably[0]) RedHat 7

-- 
thanks,
 radu
http://rgrig.idilis.ro/

[0] they are not awake yet :)

Re: glibc and ocaml/libasmrun.a

[Radu Grigore]

Update. I managed to get acces to an older distribution (RH7) and the
executable compiled with:

>   ocamlopt -ccopt -static collect_events.ml

worked in spite of:

>   /usr/local/lib/ocaml/libasmrun.a(unix.o)(.text+0x241): In function
> `caml_dlopen':
>   warning: Using 'dlopen' in statically linked applications requires
> at runtime the shared libraries from the glibc version used for
> linking

I'd still like to know what exactly is going on. I have the OCaml
compiler sources here so maybe you could provide a pointer where to
look?

-- 
regards,
 radu
http://rgrig.idilis.ro/

Re: [Caml-list] glibc and ocaml/libasmrun.a

[Olivier Andrieu]

 > Radu Grigore [Wed, 12 Jan 2005]:
 > Hello,
 > 
 > I have trouble distributing a self contained executable.
 > 
 > Two users reported "collect_events: /lib/i686/libc.so.6: version
 > `GLIBC_2.3' not found". I do not have any control over their system,
 > so I tried to link statically against glibc by using:
 > 
 >   ocamlopt -ccopt -static collect_events.ml
 > 
 > I get:
 > 
 >   /usr/local/lib/ocaml/libasmrun.a(unix.o)(.text+0x241): In function
 > `caml_dlopen':
 >   warning: Using 'dlopen' in statically linked applications requires
 > at runtime the shared libraries from the glibc version used for
 > linking

This means the runtime (libasmrun.a) contains calls to dlopen(). Now
I'm not sure why there are dlopen's in the native (ocamlopt)
runtime. I thought only the bytecode one is using dlopen (to
dynamically link stub libraries). If that is correct (ie the native
runtime doesn't actually use dlopen) then I guess you can ignore the
warning. 

-- 
   Olivier

Re: [Caml-list] glibc and ocaml/libasmrun.a

[Xavier Leroy]

> This means the runtime (libasmrun.a) contains calls to dlopen(). Now
> I'm not sure why there are dlopen's in the native (ocamlopt)
> runtime. I thought only the bytecode one is using dlopen (to
> dynamically link stub libraries). If that is correct (ie the native
> runtime doesn't actually use dlopen) then I guess you can ignore the
> warning. 

This is entirely correct.  The reason why the native-code runtime
system contains the wrappers around dlopen() is that there exists
exactly one ocamlopt-compiled program that needs them: it's ocamlc.opt,
the natively-compiled bytecode compiler, which needs to dlopen()
shared libraries to check for the existence of symbols referenced from
external declarations in the Caml source.  

So, unless the Caml program happens to embark most of ocamlc
(unlikely!), you can safely ignore the warning at static linking time.

- Xavier Leroy

Re: [Caml-list] glibc and ocaml/libasmrun.a

[Radu Grigore]

Thank you.

On Wed, 12 Jan 2005 16:45:54 +0100, Xavier Leroy <Xavier.Leroy@inria.fr> wrote:
> > This means the runtime (libasmrun.a) contains calls to dlopen(). [...]

> This is entirely correct.  The reason [...]

-- 
regards,
 radu
http://rgrig.idilis.ro/