C++ global object with destructor link error: __dso_handle

[vitaly]

Hello!

I try to compile simple C++ program. Eventually I reduced it to:

Code: Select all

class CD {
public:
    ~CD(){x=0;}
    int x;
};

CD cd;

which gives me the error:

Compiling ../tmp/1.cpp
Linking build/ch.elf
build/obj/1.o: In function `__static_initialization_and_destruction_0':
.../chibios/../tmp/1.cpp:7: undefined reference to `__dso_handle'
collect2: ld returned 1 exit status
make: *** [build/ch.elf] Error 1

I use ChibiOS 2.4.0 and code sourcery light 2011.03

Any ideas?

[Giovanni]

Are you using the arm-none-eabi compiler?

I never hit this problem because static destructors do no make much sense in an embedded system. Anyway try to Google those symbols, there are a lot of hits.

Giovanni

[vitaly]

yes, I'm using the arm-none-eabi compiler.

I agree on little sense of static destructor, but anyway...

[vitaly]

After a bit of surfing I see that it's related to dynamic libraries termination. (I don't plan to use embedded dynamic libraries for some time http://sourcery.mentor.com/public/cxx-abi/abi.html#dso-dtor

Now my question boils down to: is it enough to add this line to feel safe?

Code: Select all

extern "C" void *__dso_handle = 0;

[Giovanni]

Probably yes, do you plan to actually execute destructors or just to silence the error?

Giovanni

[vitaly]

I'd like to conceit myself they are executed
Seriously, I have 2 valid imho arguments:

• the same class may have both static and dynamic instances
• it's not uncommon to use destructors to free resources in the spirit of RAII

Anyway, from ChibiOS/RT crt0.c I believe that static destructors are called, aren't they?

[Giovanni]

They are supposed to be called.

Giovanni