template<float(*math_fun)(float)> float run_math_fun(float arg) {
float ret = (*math_fun)(arg);
return ret;
}

float ddd() {
float a = 10.0;
return run_math_fun<&fabs>(a);
}

In function 'float ob_charspace::ddd()'::
no matching function for call to 'run_math_fun(float&)'
candidate is:
template<float (* math_fun)(float)> float ob_charspace::run_math_fun(float)
[Build Error]  [obj/ob7.o] Error 1