C++ - No Code?
 

So my team is moving to C++ away from LabVIEW (which makes me want to bang my head against the wall). I've been trying to get some very simple code working (demos). Since I don't have WindRiver (my team lost the disk), I'm using ucpp to compile through the gccdist. Everything compiles/links fine, so I have a FRC_UserProgram.out , which I ftp up to the cRIO (just reimaged for C++). Then, driver station says Comm works, but claims No Robot Code even after a restart. I've verified that the .out file has uploaded successfully to /ni-rt/system .

So any ideas why the driver station still claims that there is no code?

Thanks!

PS: I've looked at the .ini files, and it appears that lvrt.out (which I assume means labview runtime) and startup.rtexe (the name of compiled labview code) are still set for startup. Don't want to toss out a red herring, but could this be it? FRC_ImageVersion.ini has Language=C, so I assume it isn't and I'm not deploying correctly (though the only file the compiler gives me is the .out file; I'm not exactly sure what I need in this case).

Anyways, thanks again.

Re: C++ - No Code?
 

Without the Wind River installation your generic compiler is probably targeting Windows rather than the VxWorks that runs on the cRIO.

Your code on the cRIO is probably starting and immediately dying on the first Windows call.

You can use Netconsole for the cRIO to check the error messages being generated. That gets installed with the FRC Utilities package. Just make sure the cRIO is setup for Netconsole (a choice during the cRIO imaging process).

The LabVIEW leftovers won't matter.

Re: C++ - No Code?
 

No, I'm 99% sure it's targeting cRIO. For one, the build directory is for PPC. I'm using the cross-compiler provided by NI (gccdist) and the very nice ucpp project (https://github.com/nikitakit/ucpp). The makefile is virtually identical to the standard one given by NI.

I would use WindRiver, if I had it. But I wasn't able to get another copy of the license file. I need to make sure that everything works correctly before build season starts though, so necessity dictates I hack something together.

Re: C++ - No Code?
 

is the cRIO imaged for C++ or LabVIEW?
just open up the imaging tool, change it, and hit apply.

Re: C++ - No Code?
 

original post:

Re: C++ - No Code?
 

I second viewing either NetConsole or the serial port output. If you have trouble interpreting it, feel free to post it here and I will do my best to help.

The ucpp project targets the cRIO, and should build code correctly. I have been using that toolchain (under Linux) for years without issues, and with a similar Makefile.

Re: C++ - No Code?
 

OK. I was able to get NetConsole working after manually changing the default gateway in ni-rt.ini to 10.6.12.4.

More interestingly, it fails to lode the code due to undefined symbol errors. The symbols look like the mangled names of WPILib functions (_Z...WatchdogC1EPi), so i assume that ucpp is not linking in WPILib.

Where is the WPILib file? I assume I could add it to StartupDlls in ni-rt.ini, or change the makefile to run wine ldppc.exe (I too am on linux) or something of the like to statically link them together.

Or have I just missed a step. Again, I haven't modified the toolchain from the default linux ucpp.

Thanks for your help.

EDIT: Found the WPILib.a file. It looks like it *should* be linked in (glancing at the makefile). Why am I getting undefined symbol errors then?

Re: C++ - No Code?
 

Got it to work - An update to version 30 of the firmware did the trick (I was using version 29).

Thanks!

Re: C++ - No Code?
 

Great.
A mismatch of the library/image versions causing the error makes sense.

Re: C++ - No Code?
 

Technically WPILib was being linked in. The failure was coming from a mismatch of symbol names between WPILib.a and the NI_FPGA.out binary that exposes symbols to access the FPGA.

Re: C++ - No Code?
 

Would you care to write up a document describing what you used and how you put it together (potentially including the Makefile you ended up with) so that others on Linux can get a head start?

Thanks,
-Joe

Re: C++ - No Code?
 

The ucpp project is just that. It is nicely packaged to make it easy to use.

https://github.com/nikitakit/ucpp

Re: C++ - No Code?
 

Excellent. Somehow I had not seen this before. Nice work.

-Joe

Re: C++ - No Code?
 

Note that the main version by nikitakit doesn't work for me - it calls python2 which is only python on some boxes. Ozzloy added a few commits to detect where python2 was installed and call that through a shell variable, so his fork might work better for many users. He submitted a pull request a long time ago but upstream hasn't merged them in.

I made some patches to some of the scripts as well, as I was getting syntax errors on my computers (Debian & openSUSE). I have a fork at github (https://github.com/rbmj/ucpp) that has ozzloy's changes as well as mine until upstream merges them in. I've also requested that ozzloy merge my changes into his repo.

Re: C++ - No Code?
 

Did not realize that, I though that was pulled a while ago. submit the pull request to nikitakit/ucpp (I just pulled ozzloy's)