[bug #30480] VM: load looks for files in the wrong directory

[bug #30480] VM: load looks for files in the wrong directory

[Luca Saiu]

URL:
  <http://savannah.gnu.org/bugs/?30480>

                 Summary: VM: load looks for files in the wrong directory
                 Project: Guile
            Submitted by: positrone
            Submitted on: Mon 19 Jul 2010 12:51:53 AM CEST
                Category: None
                Severity: 3 - Normal
              Item Group: None
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any

    _______________________________________________________

Details:

The behavior of the load function in bytecode programs is wrong and different
from interpreted programs.

* The interpreter works just like 1.8 did: loaded files are looked for in
paths relative to the directory of the script calling load.  This is the
reasonable and useful behavior.
* The virtual machine looks for the file to load in paths relative to the cwd
(I don't know if at startup time or at load time).
Absolute pathnames work in either case.

Ludovic said this when we spoke about that in Göteborg:
load should call canonicalize-path relative to the directory of the file
which loads the other one, not relative to `pwd`.

Of course this is a regression compared to 1.8.

How to reproduce the malfunction, in a particularly simple case (no explicit
relative paths in the pathnames given to load):
$ cd /tmp; mkdir q; echo '(display "b\n")' > q/b.scm; echo '(load
"b.scm")(display "a\n")' > q/a.scm
$ rm -rf ~/.cache
$ guile --no-autocompile q/a.scm
b
a
$ guile --autocompile q/a.scm
;;; note: autocompilation is enabled, set GUILE_AUTO_COMPILE=0
;;;       or pass the --no-autocompile argument to disable.
;;; compiling q/a.scm
;;; compiled /home/luca/.cache/guile/ccache/2.0-0.Q-LE-8/tmp/q/a.scm.go
ERROR: In procedure open-file:
ERROR: No such file or directory: "b.scm"





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[bug #30480] VM: load looks for files in the wrong directory

[Luca Saiu]

Follow-up Comment #1, bug #30480 (project guile):

I've written "I don't know if at startup time or at load time". Mmm. Since
the problem exists, I strongly suspect it's at startup time. Sorry for the
noise.


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[bug #30480] VM: load looks for files in the wrong directory

[Luca Saiu]

Follow-up Comment #2, bug #30480 (project guile):

Sorry again, I must be tired: there was no reason for me to suppose that load
changed the current directory.

Please ignore my previous comment.

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[bug #30480] VM: load looks for files in the wrong directory

[Ludovic Courtès]

Follow-up Comment #3, bug #30480 (project guile):

For the record, this was initially discussed at
http://thread.gmane.org/gmane.lisp.guile.bugs/4359 .

Ludo'.

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[bug #30480] VM: load looks for files in the wrong directory

[Andy Wingo]

Update of bug #30480 (project guile):

                  Status:                    None => Fixed                  
             Open/Closed:                    Open => Closed                 

    _______________________________________________________

Follow-up Comment #4:

Fixed, by turning load into a macro that expands to a call to
load-in-vicinity.  Nasty or awesome?  We report, you decide!

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Likely bug: SMOBs and mark functions [Was: Re: [bug #30480] VM: load looks for files in the wrong directory]

[Luca Saiu]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 02/13/2011 07:51 PM, Andy Wingo wrote:
> Update of bug #30480 (project guile):
> Fixed, by turning load into a macro that expands to a call to
> load-in-vicinity.  Nasty or awesome?  We report, you decide!

Awesome :-).  This solves the load problem in my old testcase, but
testing the new version helped me to expose another problem.

My code uses SMOBs with explicit GC mark funcions, as it was written for
Guile 1.8; seeing a segmentation fault occurring only in 1.9 made me
suspect of some mistake of mine, related to using SMOBs in some unsafe
way; but now I find this unlikely, and I think it's a real bug.

I've reproduced the problem by using the example in
  doc/example-smob/
which is much simpler than my own code; the failure is identical.

[luca@optimum
~/projects-by-others/guile-from-git-mainline/doc/example-smob]$ ./myguile
GNU Guile 1.9.15.114-b81eb
Copyright (C) 1995-2011 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> make-image
$1 = #<procedure make-image (_ _ _)>
scheme@(guile-user)> (define i (make-image "Whistler's Mother" 100 100))
scheme@(guile-user)> i
$2 = #<image Whistler's Mother>
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
The current thread is at (nil); Segmentation fault

gdb says that the problem is in smob.c, in the smob_mark function:
      SCM_I_CURRENT_THREAD->current_mark_stack_ptr = mark_stack_ptr;
A quick printf showed me that the SCM_I_CURRENT_THREAD macro returned NULL.

This happens on an x86_64 GNU/Linux machine, guile from today's git; 1.8
doesn't crash.

Thanks.  2.0 will seriously rock :-).

- -- 
Luca Saiu
http://www-lipn.univ-paris13.fr/~saiu
GNU epsilon: http://www.gnu.org/software/epsilon
Marionnet:   http://www.marionnet.org
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Re: Likely bug: SMOBs and mark functions [Was: Re: [bug #30480] VM: load looks for files in the wrong directory]

[Luca Saiu]

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Hash: SHA1

On 02/15/2011 12:59 PM, Luca Saiu wrote:
> The current thread is at (nil); Segmentation fault

Don't worry about the "The current thread is at (nil); ".  That was the
output of my debug printf :-), which I forgot to delete in that one
case.  Testing again on an unmodified guile:

[luca@optimum ~/projects-by-others/guile-from-git-mainline]$ cd
doc/example-smob/
[luca@optimum
~/projects-by-others/guile-from-git-mainline/doc/example-smob]$ ls
total 24
4 ChangeLog-2008  4 Makefile  4 README  4 image-type.c  4 myguile.c  4
image-type.h
[luca@optimum
~/projects-by-others/guile-from-git-mainline/doc/example-smob]$ make
cc `guile-config compile`   -c -o image-type.o image-type.c
cc `guile-config compile`   -c -o myguile.o myguile.c
cc image-type.o myguile.o `guile-config link` -o myguile
[luca@optimum
~/projects-by-others/guile-from-git-mainline/doc/example-smob]$ ./myguile
GNU Guile 1.9.15.114-b81eb
Copyright (C) 1995-2011 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> make-image
$1 = #<procedure make-image (_ _ _)>
scheme@(guile-user)> (define i (make-image "Whistler's Mother" 100 100))
scheme@(guile-user)> i
$2 = #<image Whistler's Mother>
scheme@(guile-user)> (gc)
Segmentation fault
[luca@optimum
~/projects-by-others/guile-from-git-mainline/doc/example-smob]$ gdb
- --args ./myguile
GNU gdb (GDB) 6.8.50.20090628-cvs-debian
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
(no debugging symbols found)
(gdb) run
Starting program:
/home/luca/projects-by-others/guile-from-git-mainline/doc/example-smob/myguile

[Thread debugging using libthread_db enabled]
[New Thread 0x7ffff602d710 (LWP 24847)]
[New Thread 0x7ffff582c710 (LWP 24848)]
[New Thread 0x7ffff502b710 (LWP 24849)]
[New Thread 0x7ffff482a710 (LWP 24850)]
[New Thread 0x7ffff4029710 (LWP 24851)]
[New Thread 0x7ffff3828710 (LWP 24852)]
[New Thread 0x7ffff3027710 (LWP 24853)]
[New Thread 0x7ffff1f76710 (LWP 24854)]
[New Thread 0x7ffff1775710 (LWP 24855)]
[New Thread 0x7ffff0f74710 (LWP 24856)]
[New Thread 0x7ffff0773710 (LWP 24857)]
[New Thread 0x7fffeff72710 (LWP 24858)]
[New Thread 0x7fffef771710 (LWP 24859)]
[New Thread 0x7fffeef70710 (LWP 24860)]
[New Thread 0x7fffee76f710 (LWP 24861)]
GNU Guile 1.9.15.114-b81eb
Copyright (C) 1995-2011 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> (define i (make-image "Whistler's Mother" 100 100))

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGXCPU, CPU time limit exceeded.

Program received signal SIGXCPU, CPU time limit exceeded.

Program received signal SIGXCPU, CPU time limit exceeded.

Program received signal SIGXCPU, CPU time limit exceeded.

Program received signal SIGXCPU, CPU time limit exceeded.

Program received signal SIGXCPU, CPU time limit exceeded.

Program received signal SIGXCPU, CPU time limit exceeded.

Program received signal SIGXCPU, CPU time limit exceeded.
scheme@(guile-user)> (gc)

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGPWR, Power fail/restart.

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff502b710 (LWP 24849)]
0x00007ffff7b0bc64 in smob_mark (addr=0x1945fe0,
mark_stack_ptr=0x7ffff501b1d0, mark_stack_limit=0x7ffff502aea0,
env=<value optimized out>) at smob.c:506
506	      SCM_I_CURRENT_THREAD->current_mark_stack_ptr = mark_stack_ptr;
(gdb)

- -- 
Luca Saiu
http://www-lipn.univ-paris13.fr/~saiu
GNU epsilon: http://www.gnu.org/software/epsilon
Marionnet:   http://www.marionnet.org
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Re: Likely bug: SMOBs and mark functions [Was: Re: [bug #30480] VM: load looks for files in the wrong directory]

[Ludovic Courtès]

Hi Luca!

Luca Saiu <positron@gnu.org> writes:

> I've reproduced the problem by using the example in
>   doc/example-smob/
> which is much simpler than my own code; the failure is identical.
>
> [luca@optimum
> ~/projects-by-others/guile-from-git-mainline/doc/example-smob]$ ./myguile
> GNU Guile 1.9.15.114-b81eb
> Copyright (C) 1995-2011 Free Software Foundation, Inc.
>
> Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
> This program is free software, and you are welcome to redistribute it
> under certain conditions; type `,show c' for details.
>
> Enter `,help' for help.
> scheme@(guile-user)> make-image
> $1 = #<procedure make-image (_ _ _)>
> scheme@(guile-user)> (define i (make-image "Whistler's Mother" 100 100))
> scheme@(guile-user)> i
> $2 = #<image Whistler's Mother>
> scheme@(guile-user)> (gc)
> scheme@(guile-user)> (gc)
> The current thread is at (nil); Segmentation fault
>
> gdb says that the problem is in smob.c, in the smob_mark function:
>       SCM_I_CURRENT_THREAD->current_mark_stack_ptr = mark_stack_ptr;
> A quick printf showed me that the SCM_I_CURRENT_THREAD macro returned NULL.
>
> This happens on an x86_64 GNU/Linux machine, guile from today's git; 1.8
> doesn't crash.

I can’t reproduce the problem on x86_64-linux-gnu with a recent CVS
snapshot of libgc.  Which libgc do you use?

Thanks,
Ludo’.

Re: Likely bug: SMOBs and mark functions [Was: Re: [bug #30480] VM: load looks for files in the wrong directory]

[Luca Saiu]

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Hash: SHA1

(Hello Ludovic, Andy, and all :-)).

On 02/15/2011 04:38 PM, Ludovic Courtès wrote:
> I can’t reproduce the problem on x86_64-linux-gnu with a recent CVS
> snapshot of libgc.  Which libgc do you use?

7.2.4, compiled from sources; I think I've enabled parallel collection,
but that shouldn't interfere with Guile, should it?

I'll try with the latest stable version.
Thanks,

- -- 
Luca Saiu
http://www-lipn.univ-paris13.fr/~saiu
GNU epsilon: http://www.gnu.org/software/epsilon
Marionnet:   http://www.marionnet.org
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Re: Likely bug: SMOBs and mark functions [Was: Re: [bug #30480] VM: load looks for files in the wrong directory]

[Ludovic Courtès]

Hi Luca!

Happy 2.0 release day!  :-)

Luca Saiu <positron@gnu.org> writes:

> (Hello Ludovic, Andy, and all :-)).
>
> On 02/15/2011 04:38 PM, Ludovic Courtès wrote:
>> I can’t reproduce the problem on x86_64-linux-gnu with a recent CVS
>> snapshot of libgc.  Which libgc do you use?
>
> 7.2.4, compiled from sources; I think I've enabled parallel collection,
> but that shouldn't interfere with Guile, should it?

Unless there’s a bug.  :-)

Can you try with a stock 7.2?

Thanks,
Ludo’.

Re: Likely bug: SMOBs and mark functions [Was: Re: [bug #30480] VM: load looks for files in the wrong directory]

[Luca Saiu]

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Hash: SHA1

On 02/16/2011 02:23 PM, Ludovic Courtès wrote:
> Can you try with a stock 7.2?

I've tried with the latest 7.2 tarball I've found at
http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/ , i.e. the
alpha5 of 2011-02-01; to make it quick yes, the thing worked, so the
problem probably depended on libgc.  Sorry for the noise.

Anyway, I've noticed another glitch, which again may or may not be my fault.

Testing 2.0.0 instead of git mainline.  Downloaded from ftp, configured,
compiled, installed.  The only parameter I gave configure was
- --prefix=/home/luca/usr
. I've been doing that for years: my PATH, LIBRARY_PATH,
LD_LIBRARY_PATH, and friends should be ok:
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ env |
grep home\/luca\/usr
CPLUS_INCLUDE_PATH=/home/luca/usr/include:/usr/local/include:/usr/include:/usr/X11R6/include:/usr/include/X11
MANPATH=/home/luca/usr/man:/home/luca/usr/share/man:/usr/local/man:/usr/local/share/man:/usr/man:/usr/share/man:/usr/X11R6/man:/usr/X11R6/share/man
OBJC_INCLUDE_PATH=/home/luca/usr/include:/usr/local/include:/usr/include:/usr/X11R6/include:/usr/include/X11
LIBRARY_PATH=/home/luca/usr/lib:/home/luca/usr/lib64:/lib:/usr/local/lib:/usr/lib:/usr/X11R6/lib:/lib64:/usr/local/lib64:/usr/lib64:/usr/X11R6/lib64
LD_LIBRARY_PATH=/home/luca/usr/lib:/home/luca/usr/lib64:/lib:/usr/local/lib:/usr/lib:/usr/X11R6/lib:/lib64:/usr/local/lib64:/usr/lib64:/usr/X11R6/lib64
CPATH=/home/luca/usr/include:/usr/local/include:/usr/include:/usr/X11R6/include:/usr/include/X11
PATH=/home/luca/bin:/home/luca/usr/bin:/bin:/usr/local/bin:/usr/bin:/usr/X11R6/bin
C_INCLUDE_PATH=/home/luca/usr/include:/usr/local/include:/usr/include:/usr/X11R6/include:/usr/include/X11
INFOPATH=/home/luca/usr/info:/home/luca/usr/share/info:/usr/local/info:/usr/local/share/info:/usr/info:/usr/share/info:/usr/X11R6/info:/usr/X11R6/share/info

I've found a pkg-config problem (occurring when I try to compile the
exemple-smob example with the provided Makefile) which I don't remember
seeing with git snapshots:
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$
pkg-config guile-2.0 --cflags
Package guile-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `guile-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'guile-2.0' found

This might have something to do with my unusual multiple prefixes, but
it didn't happen with snapshots!  guile-config still works fine.

Is this the problem? I have this file:
  /home/luca/usr/lib/pkgconfig/guile-2.0.pc
But nothing related to guile-2.0 in
  /home/luca/usr/lib/pkgconfig/
Now I don't have any other version of guile installed.

I've never taken the time to really understand pkg-config, and I have to
admit I'm somewhat prejudiced against it.  Anyway, now Guile should even
support installing several different versions; isn't there a clean way
of using different prefixes with pkg-config?  I really like to do that,
because this allows me to use different prefixes for differently
dangerous tests, rather than trashing /usr/local or /usr with all my
experiments.

If I ignore pkg-config for the moment and compile the SMOB example the
old way, everything works:
[luca@optimum ~/projects-by-others/guile-2.0.0/doc]$ cd example-smob/
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ ls
total 24
4 ChangeLog-2008  4 Makefile  4 README  4 image-type.c  4 myguile.c  4
image-type.h
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ gcc -c
`guile-config compile` myguile.c
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ gcc -c
`guile-config compile` image-type.c
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ gcc
`guile-config link` image-type.o myguile.o
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ ls
total 44
 4 ChangeLog-2008   4 Makefile   4 README   4 image-type.c   4 myguile.c
  4 image-type.h   4 image-type.o   4 myguile.o  12 a.out*
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ ./a.out
GNU Guile 2.0.0
Copyright (C) 1995-2011 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

And this I can't crash guile by calling gc.  So what I was speaking
about in the previous messages was indeed a false alarm.  Sorry.

Thanks for 2.0 :-)

- -- 
Luca Saiu
http://www-lipn.univ-paris13.fr/~saiu
GNU epsilon: http://www.gnu.org/software/epsilon
Marionnet:   http://www.marionnet.org
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Re: Likely bug: SMOBs and mark functions

[Andy Wingo]

On Thu 17 Feb 2011 10:41, Luca Saiu <positron@gnu.org> writes:

> I've tried with the latest 7.2 tarball I've found at
> http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/ , i.e. the
> alpha5 of 2011-02-01; to make it quick yes, the thing worked, so the
> problem probably depended on libgc.  Sorry for the noise.

NP.  Did you also enable parallel collection on that build?

> [luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$
> pkg-config guile-2.0 --cflags
> Package guile-2.0 was not found in the pkg-config search path.
> Perhaps you should add the directory containing `guile-2.0.pc'
> to the PKG_CONFIG_PATH environment variable
> No package 'guile-2.0' found

Indeed, just as you add paths to the other env vars, you need to do so
for pkg-config.

See "Environment Variables" in the pkg-config(1) man page.

> [luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ gcc -c
> `guile-config compile` myguile.c

This is really strange, for me, because I think the current guile-config
just shells out to pkg-config.  Is it possible you modified the
environment in the meantime?

> Thanks for 2.0 :-)

Thanks for the bug reports :)

Have fun with Guile,

Andy
-- 
http://wingolog.org/

Re: Likely bug: SMOBs and mark functions

[Luca Saiu]

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Hash: SHA1

On 02/17/2011 12:13 PM, Andy Wingo wrote:
> On Thu 17 Feb 2011 10:41, Luca Saiu <positron@gnu.org> writes:
> 
>> I've tried with the latest 7.2 tarball I've found at
>> http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/ , i.e. the
>> alpha5 of 2011-02-01; to make it quick yes, the thing worked, so the
>> problem probably depended on libgc.  Sorry for the noise.
> 
> NP.  Did you also enable parallel collection on that build?

Not on that build, as you requested a 'stock' GC.  Now I'm testing again
with parallel marking enabled...

>> [luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$
>> pkg-config guile-2.0 --cflags
>> Package guile-2.0 was not found in the pkg-config search path.
>> Perhaps you should add the directory containing `guile-2.0.pc'
>> to the PKG_CONFIG_PATH environment variable
>> No package 'guile-2.0' found
> 
> Indeed, just as you add paths to the other env vars, you need to do so
> for pkg-config.
> 
> See "Environment Variables" in the pkg-config(1) man page.

I will.  Thanks.

>> [luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ gcc -c
>> `guile-config compile` myguile.c
> 
> This is really strange, for me, because I think the current guile-config
> just shells out to pkg-config.

Indeed.

> Is it possible you modified the environment in the meantime?

I didn't modify the environment, but the source of guile-config explains
everything: after configuration, I see the second line of guile-config as

PKG_CONFIG_PATH="/home/luca/usr/lib/pkgconfig:$PKG_CONFIG_PATH"

, and I see that PKG_CONFIG_PATH is (at least part of) what you were
hinting at in pkg-config(1).

So, just for completeness, I'm fixing my PKG_CONFIG_PATH and testing
again; this time with parallel marking on, GC version 7_2alpha5-20110107.

[luca@optimum ~/projects-by-others/guile-2.0.0]$ export
PKG_CONFIG_PATH="/home/luca/usr/lib/pkgconfig:$PKG_CONFIG_PATH"
[luca@optimum ~/projects-by-others/guile-2.0.0]$ cd doc/example-smob/
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ make
cc `pkg-config guile-2.0 --cflags`   -c -o image-type.o image-type.c
cc `pkg-config guile-2.0 --cflags`   -c -o myguile.o myguile.c
cc image-type.o myguile.o `pkg-config guile-2.0 --libs` -o myguile
[luca@optimum ~/projects-by-others/guile-2.0.0/doc/example-smob]$ ./myguile
GNU Guile 2.0.0
Copyright (C) 1995-2011 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> make-image
$1 = #<procedure make-image (_ _ _)>
scheme@(guile-user)> (define i (make-image "Whistler's Mother" 100 100))
scheme@(guile-user)> i
$2 = #<image Whistler's Mother>
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)> (gc)
scheme@(guile-user)>

And it works.  Good :-).  Sorry again,

- -- 
Luca Saiu
http://www-lipn.univ-paris13.fr/~saiu
GNU epsilon: http://www.gnu.org/software/epsilon
Marionnet:   http://www.marionnet.org
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