error using g_idle_add() in C++, same thing works in C

Question

I need to use g_idle_add() in a C++ code, where a GSourceFunc is another class function and have to pass some arguments also. Have seen its use in C code only. So may be I am not getting the things right

While using g_idle_add() in a C code is straight forward

C program

g_idle_add ((GSourceFunc) functionA, someData);

where functionA is a function defined in that C program file scope and someData is a structure

C++ program

g_idle_add ((GSourceFunc) (mObjOfAnotherClass->functionB (* p_SomeVariable)), NULL)

Also, consider the scenario where I have to pass more than one arguments to functionB

The difference here is about the scope of functions called from g_idle_add. Can I call the g_idle_add() like I have done above in sample C++ code

nouney · Answer 1 · 2013-08-13T06:23:36.003

2

A pointer to a function is different than a pointer to a class method. You have to have an object of the class if you want to use a pointer to a method. You should wrap your method in a C function. For example:

extern "C"
{
    void myCFunction(void *p_SomeVariable)
    {
        // store your object where you want 
        static AnotherClass    mObjOfAnotherClass; 
        mObjOfAnotherClass.functionB(*p_SomeVariable);  
    }
}

And then:

g_idle_add ((GSourceFunc) myCFunction, p_SomeVariable);

edited Aug 13 '13 at 06:23

answered Aug 12 '13 at 11:47

nouney

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Thanks, What if I have to pass more than one arguments in functionB – user2618142 Aug 12 '13 at 12:13
In this case, you should pass a structure to `functionB` (and to `myCFunction` too so), which will contain all the needed data. – nouney Aug 12 '13 at 12:16

error using g_idle_add() in C++, same thing works in C

1 Answers1