Hi,
thanks, but I still have some problem when i tried to compile all lib into a static
lib.
g++ -o libCOPS.a COPS.o -L/home/kwong/thesis/codes/lib -lcops -lutil -lpthread
/usr/lib/crt1.o: In function `_start':
/usr/lib/crt1.o(.text+0x18): undefined reference to `main'
collect2: ld returned 1 exit status
make: *** [libCOPS.a] Error 1
cheers,
Kason
Joi Ellis wrote:
> On Sun, 29 Oct 2000, kason wong wrote:
>
> > Hi,
> >
> > Can i load more than one library in jni? I have 4 lib used in my program:
> > System.loadLibrary("pthread");
> > System.loadLibrary("util");
> > System.loadLibrary("cops");
> > System.loadLibrary("COPS");
> >
> > and i 've got this error msg when i run my program
> > Exception in thread "main" java.lang.UnsatisfiedLinkError: /home/kw
> > ong/thesis/codes/libutil.so: /home/kwong/thesis/codes/libutil.so: undefined
>symbol: pthread_cond_timedwait
>
> Yes, you can, but each library must not have any undefined symbols within it.
> You must be able to run 'ldd -r libyourlib.so' and not see any unresolved
> symbols. If there are, you either have a typo in your c (I typically
> forget the env-> pointer on JNI calls) or you've left a library off your
> -l list on the compile/link step.
>
> Here's what ldd -r on my library looks like:
>
> [joi@joi lib]$ ldd -r libjsystem.so
> /home/joi/lib/libnat.so => /home/joi/lib/libnat.so (0x40004000)
> /home/joi/lib/libsystem.so => /home/joi/lib/libsystem.so (0x4000d000)
> /home/joi/lib/libudpmsg.so => /home/joi/lib/libudpmsg.so (0x4001d000)
> /home/joi/lib/libuser.so => /home/joi/lib/libuser.so (0x40025000)
> /home/joi/lib/libvoip.so => /home/joi/lib/libvoip.so (0x40032000)
> libc.so.6 => /lib/libc.so.6 (0x40044000)
> /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x80000000)
>
> If I'm guessing correctly, you're thinking that if COPS depends upon pthread,
> your load order will resolve pthread symbols in COPS. I don't think it will.
> I think you must resolve all of the symbols first, and load the final result
> with loadLibrary.
>
> A failing report would look like this:
>
> [joi@joi lib]$ ldd -r libnat.so
> statically linked
> undefined symbol: nsSendNatMessage (./libnat.so)
> undefined symbol: nsSendNatMessage (./libnat.so)
> undefined symbol: nsSendNatMessage (./libnat.so)
> ...
>
> But then libnat.so is the c library, not the jni loadable library.
> If you see any undefined symbol messages in your jni loadable library, it
> won't load.
>
> That's why I'm doing in my makefile. In actuality there are about 6 libraries
> involved in my build of libjsystem, but I trimmed them to shorten the attached
> Makefile in my previous message. They only appeared as extra dependancies
> and were built using the suffice rule, so I felt their presence would only
> clutter the information. But libsystem.so actually needs bits of each for
> some calls to resolve during the link step.
>
> --
> Joi Ellis Software Engineer
> Aravox Technologies [EMAIL PROTECTED], [EMAIL PROTECTED]
>
> No matter what we think of Linux versus FreeBSD, etc., the one thing I
> really like about Linux is that it has Microsoft worried. Anything
> that kicks a monopoly in the pants has got to be good for something.
> - Chris Johnson
>
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