This is probably a stupid coding error, but the following code generates the error: C:\Program Files\Microsoft Visual Studio\MyProjects\Xrawdatafile\Xrawdatafile.cpp(32) : error C2065: 'FromAPI' : undeclared identifier I've marked the line in the listing that causes the error. It occurs in the function that creates a new datafile_type object to return to the interpreter. Right now the datafile_type object is very simple, and has but one method that prints a hardcoded string. I'm using CXX-4.?? with Visual C++ 6.0 and SP3. I'm going to download SP4 tonight and see if that helps, but any hints would be appreciated. I haven't been doing C++ for very long, so I'm probably mising something obvious. //**************************************************************************************************************** // Xrawdatafile.cpp : Defines the entry point for the DLL application. // #include "stdafx.h" #include <CXX/CXX_Objects.h> #include <CXX/CXX_Extensions.h> #include "Xrawdatafile.h" #include "datafile_type.h" BOOL APIENTRY DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) { switch (ul_reason_for_call) { case DLL_PROCESS_ATTACH: case DLL_THREAD_ATTACH: case DLL_THREAD_DETACH: case DLL_PROCESS_DETACH: break; } return TRUE; } class datafile_module : Py::ExtensionModule<datafile_module> { public: datafile_module() : Py::ExtensionModule<datafile_module>("datafile") { datafile_type::init(); add_varargs_method("datafile", &datafile_module::new_datafile,"datafile(filename)"); initialize("interface to ThermoFinnigan XRaw data files."); } virtual ~datafile_module() { }; private: Py::Object new_datafile(const Py::Tuple& args) { return Py::asObject((new datafile_type())); // THIS LINE CAUSES THE ERROR } }; extern "C" __declspec(dllexport) void initdatafile(void) { static datafile_module *dfm = new datafile_module; } //****************************************************************************************************************************