Boost Python 实现C调用python错误解决方法

由于Boost Python跟不上Python版本更新，如下方法调用可能产生TypeError: 'NoneType' object does not support item assignment异常。

Boost Python文档中例子可能产生异常。

Py_Initialize();
object main_module = import("__main__");
object main_dict = main_module.attr("__dict__");
try{
object result = exec("result = 5 + 5",main_dict);
int five_squared = extract<int>(main_dict["result"]);
cout<<"extract value : "<<five_squared<<endl;
cin>>ij;
}
catch(error_already_set){
PyErr_Print();
cin>>ij;
}

可以如下方法解决

Py_Initialize();
object main_module = import("__main__");
object main_dict = main_module.attr("__dict__");
try{
handle<> ignored((PyRun_String(

"result = 5 ** 2"

, Py_file_input
, main_dict.ptr()
, main_dict.ptr())
));
int five_squared = extract<int>(main_dict["result"]);
cout<<"extract value : "<<five_squared<<endl;
cin>>ij;
}
catch(error_already_set){
PyErr_Print();
cin>>ij;
}

Boost Python中执行表达式函数也可以正常运行。

Py_Initialize();
object main_module = import("__main__");
object main_dict = main_module.attr("__dict__");
try{
object result = eval("5 + 5",main_dict);
int five_squared = extract<int>(result);
cout<<"extract value : "<<five_squared<<endl;
cin>>ij;
}
catch(error_already_set){
PyErr_Print();
cin>>ij;
}