C:\Users\knn\AppData\Local\Temp\ccOuGKSq.ltrans0.ltrans.o: In function `setup':
C:\Users\knn\Documents\Arduino\sketch_mar24b/sketch_mar24b.ino:6: undefined reference to `testfunc()'
Not sure this is your issue, but I read one of the limitations of the Arduino IDE was it was limited to only one file. I have no experience with this but you might check it out.
JohnRob:
Not sure this is your issue, but I read one of the limitations of the Arduino IDE was it was limited to only one file. I have no experience with this but you might check it out.
Not true. Try the button on the top-right that looks like a down-pointing triangle. You can add new files there. By default they are .ino and they are all mushed into one file before sending to the compiler. But .c, .h, .cpp all work if you follow the rules.