Expose C++ obj pointers to Python API

bindings/python/context_shim.cpp

@@ -7,6 +7,7 @@
  * Please, refer to the LICENSE file in the root directory.
  * SPDX-License-Identifier: BSD-3-Clause
  */
+#include <cstdint>
 #include <pybind11/pybind11.h>
 
 #include <context_shim.hpp>
@@ -51,6 +52,8 @@ register_context(pybind11::module& m)
         .def(
             "size", [](const context_shim& c) { return c.m.size(); },
             "number of ranks within the communicator");
+
+    m.def("expose_cpp_ptr", [](context_shim* obj){return reinterpret_cast<std::uintptr_t>(&obj->m);});
 }
 
 } // namespace pyghex

bindings/python/unstructured/communication_object.cpp

@@ -7,6 +7,7 @@
  * Please, refer to the LICENSE file in the root directory.
  * SPDX-License-Identifier: BSD-3-Clause
  */
+#include <cstdint>
 #include <pybind11/pybind11.h>
 #include <pybind11/stl.h>
 
@@ -90,6 +91,8 @@ register_communication_object(pybind11::module& m)
                     return type{c.m};
                 },
                 pybind11::keep_alive<0, 1>());
+
+            m.def("expose_cpp_ptr", [](type* obj){return reinterpret_cast<std::uintptr_t>(obj);});
         });
 }
 

bindings/python/unstructured/domain_descriptor.cpp

@@ -7,6 +7,7 @@
  * Please, refer to the LICENSE file in the root directory.
  * SPDX-License-Identifier: BSD-3-Clause
  */
+#include <cstdint>
 #include <vector>
 
 #include <pybind11/pybind11.h>
@@ -53,6 +54,8 @@ register_domain_descriptor(pybind11::module& m)
                     "Returns the indices")
                 .def_property_readonly_static("__cpp_type__",
                     [type_name](const pybind11::object&) { return type_name; });
+
+            m.def("expose_cpp_ptr", [](type* obj){return reinterpret_cast<std::uintptr_t>(obj);});
         });
 }
 

bindings/python/unstructured/pattern.cpp

@@ -7,6 +7,7 @@
  * Please, refer to the LICENSE file in the root directory.
  * SPDX-License-Identifier: BSD-3-Clause
  */
+#include <cstdint>
 #include <pybind11/pybind11.h>
 #include <pybind11/stl.h>
 
@@ -68,6 +69,8 @@ register_pattern(pybind11::module& m)
                     cls.def("__call__", &pattern_container::template operator()<field>,
                         pybind11::keep_alive<0, 2>());
                 });
+
+            m.def("expose_cpp_ptr", [](pattern_container* obj){return reinterpret_cast<std::uintptr_t>(obj);});
         });
 }
 

include/ghex/unstructured/user_concepts.hpp

@@ -355,6 +355,9 @@ class data_descriptor<ghex::cpu, DomainId, Idx, T>
         assert(!(outer_stride) || (outer_stride >= (levels_first ? m_levels : m_domain_size)));
     }
 
+    /** @brief empty constructor*/
+    data_descriptor(){}
+
     // member functions
 
     device_id_type device_id() const noexcept { return arch_traits<arch_type>::default_id(); }