Re: Undefined procedure on foreign library in 6.6.4

FYI.. this is running under Ubuntu 13.10, whereas my last successful 
foreign library build was Ubuntu 12.04 LTS.  I can't comment/not tried 
12.10 or 13.04.

On 02/04/14 17:52, Jan Wielemaker wrote:
> On 04/02/2014 04:54 PM, jon judge wrote:
>> Hi,
>>
>> I successfully installed 6.6.4 using your apt-add-repository
>> ppa:swi-prolog/stable url (not from source),  All worked perfectly first
>> time - I can run swipl.
>>
>> But now I'm hitting issues accessing a foreign library predicate that
>> appears to build correctly. I've removed nearly all the code to simplify /
>> reproduce:
>>
>> #include <SWI-Prolog.h>
>>
>> static foreign_t testfo(void)
>> {
>> 	PL_succeed;
>> }
>>
>> install_t install_libtestfo()
>> {
>>    PL_register_foreign("testfo", 0, testfo, 0);
>> }
>>
>> When I build the above from eclipse as a shared object, it compiles no
>> problem, creating the shared object:
>>
>> -rwxr-xr-x 1 jon  jon    41531 Apr  2 15:18 libtestfo.so
>>
>> Now I link to swipl:
>>
>> # swipl-ld -v -shared -o libtestfo ../testfo.c
>> 	eval `swipl --dump-runtime-variables`
>> 		CC="gcc"
>> 		PLBASE="/usr/lib/swi-prolog"
>> 		PLARCH="i386"
>> 		PLLIBS=""
>> 		PLLIB="-lswipl"
>> 		PLCFLAGS="-fno-strict-aliasing -pthread -fPIC -D_FORTIFY_SOURCE=2 -fPIC
>> -I/usr/include/ncursesw"
>> 		PLLDFLAGS="-rdynamic -Wl,-Bsymbolic-functions -Wl,-z,relro -g -O2
>> -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security
>> -pthread"
>> 		PLSOEXT="so"
>> 		PLTHREADS="yes"
>> 	gcc -c -fpic -fno-strict-aliasing -pthread -fPIC -D_FORTIFY_SOURCE=2 -fPIC
>> -I/usr/include/ncursesw -D_REENTRANT -D__SWI_PROLOG__
>> -I/usr/lib/swi-prolog/include -o ../testfo.o ../testfo.c
>> 	gcc -o libtestfo.so -shared -rdynamic -Wl,-Bsymbolic-functions -Wl,-z,relro
>> -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat
>> -Werror=format-security -pthread ../testfo.o -L/usr/lib/swi-prolog/lib/i386
>> -lswipl
>> 	rm ../testfo.o
>>
>> .. no errors.  The new library is definitely built.. timestamp updated, and
>> file size has increased compared to the version above.
>>
>> -rwxr-xr-x 1 root root 1237082 Apr  2 15:20 libtestfo.so
>>
>> Check the symbols are in there:
>>
>> root@phoenix:/home/jon/Dev/testfo/Debug# nm libtestfo.so | grep testfo
>> 0000e4b5 T install_libtestfo
>> 0000e4ab t testfo
>>
>> .. all ok.
>>
>> Now in prolog, testfo.pl containing a single line:
>>
>> :- use_foreign_library(foreign('/home/jon/Dev/testfo/Debug/libtestfo.so')).
>>
>> This loads correctly, so it has found the install predicate etc..
> Well, copy-and-pasting the commands from swipl-ld and editing them a
> little, it turns out that the fatal option is -Wl,-Bsymbolic-functions.
> Once you delete that from the link command, all works just fine. I don't
> understand why (see man ld for what the option does). It indeed does
> call the install function (verified with an Sdprintf() call in there).
> But, it seems it is not really calling PL_register_foreign() inside
> Prolog.
>
> If I run Prolog under gdb and put a break on PL_register_foreign, it
> nicely breaks, but this seems a different PL_register_foreign(). If I
> put a breakpoint in a function called by PL_register_foreign(), it no
> longer breaks, so it indeed does not seem to be calling
> PL_register_foreign() in Prolog itself.
>
> Before this can be fixed, we must know what is going on.  Anyone?
>
> Maybe our Debian maintainer (Eugeniy) has an idea?
>
> 	Cheers --- Jan
>
>> 5 ?-
>> pdt_reload:pdt_reload(['/home/jon/Dev/pl/testfo.pl']).
>> |    % /home/jon/Dev/pl/testfo.pl compiled 0.00 sec, 5 clauses
>> true.
>>
>> But I get undefined procedure when trying to access it:
>>
>> 6 ?- testfo.
>> ERROR: [Thread pdt_console_client_0_Default Process] toplevel: Undefined
>> procedure: testfo/0 (DWIM could not correct goal)
>>
>> It's always tempting to make 1+1=3, but someone else hit the similar
>> symptoms today:
>>
>> http://stackoverflow.com/questions/22811055/why-am-i-not-able-to-load-this-c-code-in-prolog-in-linux-but-i-am-able-in-os-x
>>
>> I have successfully done this before lots of times on 6.2.6 compiled from
>> source.. but for this install I'm on a completely new machine using
>> packages, and wondering what I am doing wrong.. / have forgotten / how the
>> process is different.
>>
>> Thanks,
>> Jon.
>>
>>
>>
>>
>> --
>> View this message in context: http://swi-prolog.996271.n3.nabble.com/Undefined-procedure-on-foreign-library-in-6-6-4-tp14676.html
>> Sent from the SWI Prolog mailing list archive at Nabble.com.
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