If you pass it to a function like that, it passes it by value even if
it's a pointer. So it's calling the copy constructor (which you haven't
defined so it isn't printing "A start"), rather than the regular
constructor, and then destructing it.
To pass an actual pointer rather than sending it by value, you need to
do it like this:
| B() { aa=new A; }
~B() { delete
aa; }
void run(object ct) {
_obj=ct(); //creat a python object
_obj.attr("fun1")(ptr(aa)); //call a function named "fun1" with a
pointer arg
_obj.attr("fun2")(ptr(aa)); //call a function named "fun2" with a
pointer arg
}
A*aa;
object _obj;|
Note that both "aa" objects are wrapped by a call to "ptr()"
Just be careful with the python when doing this, as it can cause a crash
if python tries to access that object after its C++ lifetime has ended.
So always make sure the python object's lifetime ends before the C++
object's does.
On 12/22/2012 4:45 PM, simon zhang wrote:
when I call python's function with pointer as an argument in
boost.python, there are some troubles in destructor. The following is
a sample code
|#include <boost/python.hpp>
#include <boost/python/module.hpp>
#include <boost/python/def.hpp>
#include <string>
#include <iostream>
using namespace boost::python;
class A{
public:
A() {
std::cout<< "A start"<<std::endl;
}
~A() {std::cout<< "A end" <<std::endl;}
}
class B{
public:
B() { aa=new A
; }
~B() { delete
aa; }
void run(object ct) {
_obj=ct(); //creat a python object
_obj.attr("fun1")(aa); //call a function named "fun1" with a pointer
arg
_obj.attr("fun2")(aa); //call a function named "fun2" with a pointer
arg
}
A*aa;
object _obj;
}
BOOST_PYTHON_MODULE(ctopy)
{
class_<A> ("A",init<>())
;
class_<b> ("B",init<>())
.def("run",&B::run)
;
}|
python:
|import ctopy
class tc:
def fun1(self,tt):
print"fun1"
def fun2(self,tt):
print"fun2"
bb=ctopy.D()
bb.run(tc)|
this result:
|A start
fun1
A end
fun2
A end
A end|
note:
The "A end" has been printed three.I try it in "valgrind",there are
some errors.I just want to run the destructor once.How to do?
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