[C++-sig] pass function pointer to c extension function in python

[Qinfeng(Javen) Shi]

Dear All,

I used a global function pointer op, so that when op = add, it operates as
add, when op = minus, it operates as minus. I used a function choose_op() to
set op = add or minus. It works if I call choose_op() inside other function
exposed in python. It reported a error when I used bjam to compile it if I
exposed it into python.

Any suggestion will be appreciated. Thanks in advance.


---------------------------c extension---------------------
float add(float a, float b){
    return a+b;
}
float minus(float a, float b){
    return a-b;
}
float (*op)(float a, float b) = add;
void choose_op(float (* method)(float a, float b)){
    op = method;
}
int funcPtrTest()
{
    float a,b,c;
    a = 1;
    b = 2;
    c = -10;

    choose_op(minus);
    c = op(a,b);
    printf("%f\n",c);
   return 0;
}

BOOST_PYTHON_MODULE(hello){
def("funcPtrTest", &funcPtrTest);
def("choose_op",&choose_op);// this line makes bjam report an error. Without
it is ok. But without it also means we can't call it directly in python.
}
------------------------result-------------
(1)if without def("choose_op",&choose_op),
>>> import hello
>>> c = hello.funcPtrTest()
-1.000000
so it works.

(2)if with def("choose_op",&choose_op),
It can't be compiled successfully by bjam.
/boost_1_33_1/boost/type_traits/add_cv.hpp:34: error: `const
   volatile' qualifiers cannot be applied to `float ()(float, float)'


-- 
Qinfeng(Javen) Shi

Research School of Information Sciences and Engineering
Australian National University
Locked Bag 8001
Canberra ACT 2601
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