Re: [Gcl-devel] New user question - more explicit information concerning shared library use

[Camm Maguire]

BTW, as a heavy gcl-tk user, just in case you have any windows (mingw)
expters at your site who might be able to spare a few hours getting
this working on the mingw port, that would be most appreciated.  It
appeasrs as though there will be at least one other serious gcl-tk
user in the medium term -- axiom.

Take care,

Jordan Rosenthal <address@hidden> writes:

> Hi all,
> 
> We have a fairly large codebase for image processing that was
> developed on top of an older version of GCL (it is currently running
> on top of 2.4.4).  Here's a little bit of info about what we're running
> 
> -------
> - Linux OS (although we had a version on Solaris)
> - GCL 2.4.4
> - extensive use of the GCL to TCL/TK 8.4 link
> - On top of the TCL/TK we have built the BLT library extension (this
> does not affect the GCL build directly) and a custom TK extension
> - Our system loads in a bunch of compiled files on top of GCL and does
> a si::save to create a new image
> -------
> 
> One of the biggest annoyances I have with our system is that it is
> really painful to use external C and LISP libraries.  For C libraries,
> we have been using the EXTRAS make variable to link in certain
> symbols, but this is not fun to do.  External LISP libraries never
> seem to work out of the box, because most of them are dependent on
> some of the newer ANSI features (e.g., objects don't exists in GCL
> 2.4.4).
> 
> Lo and behold, I've recently out found that newer versions of GCL are
> being worked on by the group reading this email!  It is moving towards
> ANSI compliance and apparently has the ability to link to shared
> libraries with the compiler::link command.  (I have also seen posts
> regarding the gcl-elf-loader that can do this at runtime.)
> 
> I downloaded GCL 2.6.6 and have compiled without any (major)
> issues. However, I am having trouble with a few things in the new
> version:
> 
> 1) There are a bunch of configure options to get dynamic loading of
> compiled files (e.g., static bfd, local bfd, dynamic bfd, dlopen,
> etc). Which is the preferred method?  Currently, I am using the
> dynamic bfd (i.e., the shared bfd libraries on my system).  Also, how
> does the gcl-elf-loader fit into the picture?
> 
> 2) How do I use the compiler::link command?  The syntax is
> straight-forward, but whenever I do it I get errors.  I have tried
> both using and not using the system-p key, but in either case I get
> some sort of error.  In one case (I can't remember which) I get a
> "cannot relocate" error.  In the other case I get a "multiple
> instances of init_code defined" error.
> 
> I think my problems most likely stem from a lack of understanding
> about how GCL works internally, especially in regard to dynamic
> loading of object files.  Also, I've only been using LISP (the GCL
> 2.4.4 variety) for a little while now so sometimes that can be a
> little bit of a block.
> 
> If anyone could give me a brief tutorial (or point me to some reading
> material) on how this stuff works, I'd really appreciate it.  I've
> reversed engineered some of the code, but that is slow going and some
> sort of overview would be much appreciated.
> 
> Perhaps if it is simpler, we could work with a toy problem.  Let's say
> I have an external shared library...maybe the BLAS numerical library
> or the libxml2 library on Linux.  How do I create an image that let's
> me link to all the symbol's in these (shared) libraries from a clines
> construct later on?
> 
> Any help will be much appreciated.
> 
> Thanks,
> 
> Jordan Rosenthal
> 
> PS I also noticed a gcl-users mailing list, but I didn't post there
> because it seems to have very little activity.  If the gcl-devel list
> is not the right place to post this question, just let me know and
> I'll move this discussion to the gcl-users list.
> 
> 
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> 
> 
> 

-- 
Camm Maguire                                            address@hidden
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