topic Re: Metrowerks compiler issue in Classic/Legacy CodeWarrior

Metrowerks compiler issue

cw_Potz — Wed, 17 Aug 2011 16:11:15 GMT

Hello all,

I have 2 functions, both are identical except that one function is a template function. When I send the functions as function_pointer arguments to some other function, Metrowerks compiler complains for the template function.

template <typename T>
static void
call_stub (void *argument)
{

...........

..............
}

static void
call_stub_ (void *argument)
{

...........

..............

}

void register_callback ( (void (*)())(&call_stub<T>) ) ---- Gives error

void register_callback ( (void (*)())(&call_stub_) ) ---- Works fine.

Error Description:

Illegal explicit conversion from 'void' to 'void (*)()'.

Am I missing something here ? Is it a problem with the Metrowerks compiler ?

I am using PowerPC EABI Linker. Version: Code Warrior PowerPC ISA, Release 8.5 Build 50425.

Thanks !!

Re: Metrowerks compiler issue

Lundin — Wed, 17 Aug 2011 19:52:48 GMT

I haven't used C++ in Codewarrior but a qualified guess is the classic problem with linking of template functions:

http://www.parashift.com/c++-faq-lite/templates.html#faq-35.12

Whether Codewarrior supports export keyword or not, I have no idea.

Re: Metrowerks compiler issue

CompilerGuru — Thu, 18 Aug 2011 11:36:12 GMT

as the error is a compilation failure and not a link time failure, I doubt it is that issue.

I would recommend to show a complete example and not just snippets, there is just too much undefined otherwise.

The text "void register_callback ( (void (*)())(&call_stub<T>) )" is not legal in C++ code as

it is neither a declaration nor a statemen, seems to be some psedocode.

Either way only a concrete instance of the call_stub template function has an address (call_stub<int>), the address of call_stub<T> only makes sense if used inside of another template.

Daniel

Re: Metrowerks compiler issue

cw_Potz — Thu, 18 Aug 2011 20:57:50 GMT

Actually the project on which I am working is quite a big one. So I just wrote the minimum stuff. Please check the code below, maybe better than previous time.

Thanks !!

class MyThread
{
    template <typename T>
    static void
    call_stub (void *argument)
    {
    }

    static void
    call_stub_ (void *argument)
    {
    }

public:
    template <typename T>
    MyThread (T &function, bool joinable = false)
    {
        int result = register_callback ((void (*)())(&call_stub<T>), joinable, (void*)&function);

        int result = register_callback ((void (*)())(&call_stub_), joinable, (void*)&function);

    }
};

int
register_callback(

void (*entryAddr)(void),

bool joinable,

void *arg

)

{
// creates a thread and register the callback function.
}