How to call the Non Member function from the class constructor

Question

I have a C code function, which I need to call from the class constructor.

Class a{
.....
}
//Included the header file in the class and
//declared the function globally as extern 
extern void ab(void); //function available in the c code 
a::a() //constructor of class a
{
::ab(); //calling the non member function - giving an error
}

It is giving an error : undefined reference to `ab()'

Can anyone help me to solve this issue?

I solved this error by adding the extern "C" void ab(); before it calls. — tharunkumar, Mar 24 '16 at 09:03

Serge · Answer 1 · 2016-03-24T05:19:44.477

1

Judging simply from the code and error supplied, it look as if you have not DEFINED your function. You have DECLARED it, but the compiler is complaining that it cannot find that function's implementation. To resolve this, provide an implementation for your function e.g.

void ab(void)
{
    int x = 0;
    printf("My int: %d", x);
}

edited Mar 24 '16 at 05:19

answered Mar 24 '16 at 05:18

Serge

634
4
9

ab() function is calling the another function, which is doing the serial bus initialization with the predefined values. – tharunkumar Mar 24 '16 at 06:49

score -2 · Answer 2 · answered Mar 24 '16 at 05:17

-2

Send pointer as a parameter to the constructor:

a::a(void (*ptrFun)(void) )
{
     ptrFun();
}

answered Mar 24 '16 at 05:17

Rafał

19
5

how can I send a nonmember function pointer as a parameter to the constructor? – tharunkumar Mar 24 '16 at 05:22
Is there any way that I can achieve through extern keyword .? – tharunkumar Mar 24 '16 at 05:37
Or just try to define global function before class definition. For me it works. – Rafał Mar 24 '16 at 05:40
thanks Rafal, Please find the above edited one – tharunkumar Mar 24 '16 at 07:03

How to call the Non Member function from the class constructor

2 Answers2