Problem with wiringPi

Are these messages happening at compile time or at link time?

I suspect its not that these are not defined in the header but that you aren't linking in the wiringPi library at link time...

Maybe I should not use Geany, but compile and link manually in a terminal window. Must find out how to do that then. Sorry for my incompetance.

But I am using Geany, which under the "Build" main menu (among others) have the options Compile, Build, Make, Make Custom Target, Make Object and Execute. No menu for linking. I am using Compile, Build and Execute. After your reply I also tried Make. I have now tried all the menu points listed above, with the following results: Compile, Make, Make Object all (with blink.c active in Geany) run successfully. Build gives the error messages described in my first message. Execute results in a terminal window with thism text: /tmp/geany_run_script_6LY5G0.sh: 7: /tmp/geany_run_script_6LY5G0.sh: ./blink: not found

Geany uses these compile commands for C++:

-Compile: g++ -Wall -c "%f"

-Build: g++ -Wall -o "%e" "%f"

------------------ (program exited with code: 127) Press return to continue

I am getting closer now: Did a new build of wiringPi and saw the following message in the terminal: NOTE: To compile programs with wiringPi, you need to add: -lwiringPi to your compile line(s) To use the Gertboard, MaxDetect, etc. code (the devLib), you need to also add: -lwiringPiDev to your compile line(s).

So I added the text "-lwiringPi" to the compile and build commands in Geany. Now I only get the following error message when running a build: g++ -wall -o -lwiringPi "blink" "blink.c" (in directory: /home/pi/wiringpi/examples) g++: error: blink: no such file or directory Compilation failed. There is a file blink.c in directory home/pi/wiringpi/examples, so something else is nagging Geany, but what?

Best regards.

Most of us set up a make file when doing more than trivial C compilations, and execute the compilation by running 'make'. Did you do that?

If not its worthwhile to create a makefile, despite the slightly archaic format (TAB is required in some lines - spaces are not an acceptable substitute) because

(a) its quite concise and describes all the steps needed to compile something together with the dependencies such as needing all modules to have been compiled before linking and which source files are needed to compile each module.

(b) make is generally faster than other approaches because make always does the the minimum amount of work needed to compile a program, e.g. if you only edited the source for one C module, then make only compiles that module before re-linking the executable.

You're trying to compile the source files called 'blink' and 'blink.c' and create an output file called '-lwiringPi'. In other words, your command line is the wrong way round. It should be:

g++ -Wall -lwiringPi -o blink blink.c

I'd suggest writing a Makefile to run the compilation and getting geany to invoke that. I wouldn't trust editors to know how to compile things right themselves (unless they're an IDE, in which case they have a million dialogues you need to fill out to get it to build)

Theo

-Build needs a -lwiringPi

wrong order

.... -o blink -lwiringpi blink.c

Now I have success thanks to The Natural Philosopher, Theo and Martin Gregorie. Thank you for taking your time to answer. It really was a case of RTFM on my side, but the manual was so HUGE :-)

Best regards.

We have all done it...

It's why Makefiles were invented, as, once edited, you just type 'make' and correct the latest spew of errors until it all works

Only geeks want to understand the command line syntax of gcc. The rest of is get it right ONCE and copy and edit that makefile :-)

Thx

There is NO currently supported wiringPi source code download, at least none by me, the author, so I've no idea where you're getting the source from. If you're using Raspbian, then sudo apt-get install wiringpi, however read this and pick another GPIO library

And remember; wiringPi is intended for experienced C and RTB BASIC users only. It's not a newbie learning tool.

Gordon

Jesper,

I hope you do know/remember that the actual building also needs to be told which library to use (using "-lwiringPi" as an argument to GCC) ? The header file just describes which functions and such should be in that library.

The thing is, Geany is just a front-end for GCC, so you need to dive into it and alter the "build" commandline:

How to do it:

Geany toolbar -> "build" -> "Set build commands" -> "C commands" -> "build" -> textbox directly right of it (starting with "gcc -Wall") Append "-lwiringPi" to the end of that line.

Hope that helps.

Regards, Rudy Wieser

Hello Gordon, and thank you for the reply. First I would like to say that I did not mean to bother you with a newbie question, but hoped that some of the "regulars" on this group could help. And they sure did help. Now I can read and write to the GPIO from programcode, thanks to your wiringPi library and the kind help I recieved. The link you put in above was one of the places I visisted, so I know that you are not supporting wiringPi anymore. I googled "raspberry gpio c" to find ways of reaching the GPIO from programcode, and got several links to wiringPi stuff, so I set out to use that. If anyone can suggest a simpler C-library to use, I would be gratefull. I had a look at the code in wiringPi.c, and got blown away :-) For now wiringPiSetup, pinMode, digitalRead and digitalWrite is al I use.

Best regards

Rudy:

Hi Rudy, Yes, I had not put in "-lwiringPi in Geanys build-command. I now have this: gcc -Wall -lwiringPi -o "%e" "%f" , and things started working perfect.

Best regards

Jesper,

Great. :-)

Only after I posted (and looked back into the newsgroup) I noticed that your question was already several days old, and thought that you might have found the answer by now (and my suggestion would be like mustard after the meal). :-\

Regards, Rudy Wieser

I may yet want to use the GPIO and wiringPi looks like its what I would use, too.