Problem with QTRSensors Arduino library with ATTiny84

Hi, I am trying to use the QTRSensors Arduino library with an ATTiny84 processor, but the code will not compile. I am using the out of the box sample sketch QTRAExample, and get the following error when I try to validate the program prior to uploading to the ATTiny:

QTRSensors\QTRSensors.cpp.o:(.rodata._ZTV10QTRSensors+0x4): undefined reference to `__cxa_pure_virtual’

Please help! Thanks.

–Rob Klingberg

Hi all, update to this: after several hours of tinkering with the QTRSensors.cpp file, deleting sections I didn’t need, and also after adding this line to the .cpp file to trap the __cxa_pure_virtual error:

extern “C” void __cxa_pure_virtual() { abort(); }

I got things to the point where I could compile for the ATTiny84. Challenge is, the code doesn’t work. I loaded the same code onto an Arduino Uno and it works like a champ. Any idea what could be causing the issues? My ATTiny cores say they support delayMicroseconds() and the other functions used by the QTRSensors files. I wonder if it has something to do with the clock speed of the 84 (only 8mhz) vs. the Uno (16mhz)?

Still looking for help as I’d really love to get this working.