keep_alive call policy (analogous to Boost.Python's with_custodian_and_ward, fixes #62)
diff --git a/example/example13.cpp b/example/example13.cpp
new file mode 100644
index 0000000..782db31
--- /dev/null
+++ b/example/example13.cpp
@@ -0,0 +1,37 @@
+/*
+ example/example13.cpp -- keep_alive modifier (pybind11's version
+ of Boost.Python's with_custodian_and_ward / with_custodian_and_ward_postcall)
+
+ Copyright (c) 2015 Wenzel Jakob <wenzel@inf.ethz.ch>
+
+ All rights reserved. Use of this source code is governed by a
+ BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "example.h"
+
+class Child {
+public:
+ Child() { std::cout << "Allocating child." << std::endl; }
+ ~Child() { std::cout << "Releasing child." << std::endl; }
+};
+
+class Parent {
+public:
+ Parent() { std::cout << "Allocating parent." << std::endl; }
+ ~Parent() { std::cout << "Releasing parent." << std::endl; }
+ void addChild(Child *) { }
+ Child *returnChild() { return new Child(); }
+};
+
+void init_ex13(py::module &m) {
+ py::class_<Parent>(m, "Parent")
+ .def(py::init<>())
+ .def("addChild", &Parent::addChild)
+ .def("addChildKeepAlive", &Parent::addChild, py::keep_alive<1, 2>())
+ .def("returnChild", &Parent::returnChild)
+ .def("returnChildKeepAlive", &Parent::returnChild, py::keep_alive<1, 0>());
+
+ py::class_<Child>(m, "Child")
+ .def(py::init<>());
+}