Has anybody gotten NetworkTables to work on a RaspberryPi

[JohnRLewis]

Here is my jar, but I suspect that it is going to work for you too.

https://github.com/JohnRudolfLewis/n...ntcoreblah.jar

I believe there is a difference between our environments. On your Pi, when you run ldd libntcore.so, how does your output differ from mine below?

pi@raspberrypi:~ $ ldd libntcore.so
./libntcore.so: /usr/lib/arm-linux-gnueabihf/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by ./libntcore.so)
./libntcore.so: /usr/lib/arm-linux-gnueabihf/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by ./libntcore.so)
linux-vdso.so.1 (0x7eded000)
/usr/lib/arm-linux-gnueabihf/libarmmem.so (0x76f6d000)
libstdc++.so.6 => /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 (0x76e7a000)
libgcc_s.so.1 => /lib/arm-linux-gnueabihf/libgcc_s.so.1 (0x76e4d000)
libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0x76d10000)
/lib/ld-linux-armhf.so.3 (0x54aef000)
libm.so.6 => /lib/arm-linux-gnueabihf/libm.so.6 (0x76c95000)

[Thad House]

Originally Posted by JohnRLewis

Here is my jar, but I suspect that it is going to work for you too.

https://github.com/JohnRudolfLewis/n...ntcoreblah.jar

I believe there is a difference between our environments. On your Pi, when you run ldd libntcore.so, how does your output differ from mine below?

pi@raspberrypi:~ $ ldd libntcore.so
./libntcore.so: /usr/lib/arm-linux-gnueabihf/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by ./libntcore.so)
./libntcore.so: /usr/lib/arm-linux-gnueabihf/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by ./libntcore.so)
linux-vdso.so.1 (0x7eded000)
/usr/lib/arm-linux-gnueabihf/libarmmem.so (0x76f6d000)
libstdc++.so.6 => /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 (0x76e7a000)
libgcc_s.so.1 => /lib/arm-linux-gnueabihf/libgcc_s.so.1 (0x76e4d000)
libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0x76d10000)
/lib/ld-linux-armhf.so.3 (0x54aef000)
libm.so.6 => /lib/arm-linux-gnueabihf/libm.so.6 (0x76c95000)

I get the same output too. Thats why you have to call LD_PRELOAD before you run your program. LD_PRELOAD allows you to specify a different library as the dependency. So if you LD_PRELOAD to the libstdc++.so.6 found here http://198.199.94.5/ntcore/libstdc++.so.6 it will load that one before trying to load the default one and should work.

[JohnRLewis]

I believe I am following your instructions properly, this is the command I am running to launch my jar:

env LD_PRELOAD=/home/pi/libstdc++.so.6 java -jar ntcoreblah.jar

But I still get the error. Is my syntax wrong? Is there yet another dependency that I need to preload? Is there something I need to install on my Pi in order for that environment variable to take effect?

Thank you so much for continuing to reply and not giving up on me!

[JohnRLewis]

D'oh.... I already had a version of libstdc++.so.6 in my folder from some previous troubleshooting. When I did a wget on your version, it was not overwriting it for some reason. Gah... I feel like an idiot. Error resolved.


THANK YOU so much for spending so much time with me on this.

[axton900]

Hey guys!
I am currently trying to do what you were doing and was wondering how you were able to be successful. I was able to get NetworkTables working well in C++ but not Java. I try doing what you did where you loaded the ntcore library but I keep getting a NoClassDefFoundError.
Thanks! I really appreciate it!!