Compilation error using arduino-mk on arch Linux (undefined reference to __dso_handle)

Question

1. I'm compiling a simple sketch that reads values from an analog input and activates a buzzer on a digital input.
2. working on an Arduino uno.
3. the sketch compiles and runs fine on windows and arch linux using the Arduino IDE.

I recently tried to start working with Arduino-mk, I tried to compile the said sketch and got the following compiler error (analogVal is the variable holding the analogRead):

/usr/bin/avr-gcc -mmcu=atmega328p -Wl,--gc-sections -Os -o /home/niv/Gits/bin/uno/maglove/maglove.elf

~/Gits/bin/uno/maglove/maglove.ino.o ~/Gits/bin/uno/maglove/libcore.a -lc -lm 
/home/niv/Gits/bin/uno/maglove/maglove.ino.o: In function `_GLOBAL__sub_I_nothing':
maglove.ino:(.text.startup._GLOBAL__sub_I_nothing+0xc): undefined reference to `__dso_handle'
maglove.ino:(.text.startup._GLOBAL__sub_I_nothing+0xe): undefined reference to `__dso_handle'
maglove.ino:(.text.startup._GLOBAL__sub_I_nothing+0x18): undefined reference to `__cxa_atexit'
/usr/bin/avr-ld: /home/niv/Gits/bin/uno/maglove/maglove.elf: hidden symbol `__dso_handle' isn't defined
/usr/bin/avr-ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
/home/niv/Gits/Arduino-Makefile/Arduino.mk:1416: recipe for target '/home/niv/Gits/bin/uno/maglove/maglove.elf' failed
make: *** [/home/niv/Gits/bin/uno/maglove/maglove.elf] Error 1
make: Target 'all' not remade because of errors.

I am not very experienced with Arduino yet, and google has failed me in finding this error or any keyword from it in the context of Arduino uno.

thanks.

• Mikael Patel: Please add the compile line. And google "__dso_handle".
• NivPgir: @Mikael I added the compile line. anything before that is just library compilations that go smoothly

Answer 1

I can't say I fully understand what is going on, but it seems that if you add:

void * __dso_handle;

You may be able to eliminate one of the problems. You might try the same trick with __cxa_atexit as well.

I found the idea by searching on:

arduino __dso_handle

This is the webpage that I found that suggested the void * hack.

• NivPgir: weirdly... That worked! however it seems like an ugly workaround, I would prefer to understand whats causing this error and fix it on my Linux machine since the code needs to be good to compile on windows too, and something tells me adding these declarations might break it when compiling on windows.