Mailman 3 April 2004 - Cplusplus-sig

Re: [C++-sig] Re: init function not found [was Re: Problem with
by Aashish Chaudhary April 6, 2004

April 6, 2004

Thanks raul that was a silly mistake :( ... I should have noticed that .. > I didn't know that VC7.0 support had been dropped - at least, not > deliberately! Well that link that you sent in the some mail (on feb 03) (the status of the compilers) showed that there were couple of problems with the VC7.0 but nothing reported for 7.1.. I got the CVS version compiled on Linux .. :) > This looks very confusing to me, because the error message doesn't > seem to match up to what you "did" in Python. Maybe the problem is > very simple though. If you create a shared object called > register_ptr.so you can import it with "from register_ptr import > ....". Python then looks for a Python module or shared object that > matches that name, and in the case of a shared object loads it and > looks for a function called something like initregister_ptr. The > BOOST_PYTHON_MODULE(register_ptr) macro gives you this function, > correctly named. > > > ____________ Problem solved !! Thanks! regards, Aashish ___________________________________ > C++-sig mailing list > C++-sig(a)python.org > http://mail.python.org/mailman/listinfo/c++-sig > __________________________________________________________________________ Aashish Chaudhary Research Assistant Iowa State University E-Mail: aashish(a)iastate.edu Ames, Iowa Telephone: +1 515-441-1178

5 7

IT talents for lowest prices
by Carson Mcfarland April 6, 2004

April 6, 2004

1 0

Symbol visibility patch for GCC v3.4
by Niall Douglas April 5, 2004

April 5, 2004

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 If people could test this patch and let me know, I'd be most grateful. Some might consider this off-topic, so I'll give you a quick run down of the improvements - with my Boost.Python built bindings, my shared object went from >200,000 symbols down to just 19,738 resulting in the six minute load time dropping to a few seconds. If you examine the dynamic table with nm, the output is vastly cleaner with only what is actually required being exported - this will beat any linker version script method hands down. Also, because the compiler now knows what symbols don't need to run through the relocation table, it can substantially optimise code output with better inlining, half the overhead of calling a function, much better ability to totally elide unnecessary code and many other benefits. See Ulrich Drepper's "How to Write Shared Libraries" article. To install, get a GCC v3.4 from CVS. Apply patch. Find the header file boost/boost/python/detail/config.hpp. Modify the dllexport section to: #if defined(BOOST_PYTHON_DYNAMIC_LIB) # if (defined(_WIN32) || defined(__CYGWIN__)) # if defined(BOOST_PYTHON_SOURCE) # define BOOST_PYTHON_DECL __declspec(dllexport) # define BOOST_PYTHON_BUILD_DLL # else # define BOOST_PYTHON_DECL __declspec(dllimport) # endif # elif (defined(__GNUC__) && __GNUC__ >= 3 && __GNUC_MINOR__ >=4) # if defined(BOOST_PYTHON_SOURCE) # define BOOST_PYTHON_DECL __attribute__ ((visibility("default"))) # define BOOST_PYTHON_BUILD_DLL # else # define BOOST_PYTHON_DECL # endif # endif #endif Adjust the Jamfile to include a <cxxflags>-fvisibility=hidden for the dll boost_python. Recompile everything using -fvisibility=hidden for your binding source files too. You should see a substantial improvement in link times and your shared objects will have reduced in size, sometimes by tens of megabytes. Everything should run just as before. If it doesn't, please let me know - everything on my end runs just as before. Cheers, Niall -----BEGIN PGP SIGNATURE----- Version: idw's PGP-Frontend 4.9.6.1 / 9-2003 + PGP 8.0.2 iQA/AwUBQHGUrcEcvDLFGKbPEQJwfQCeJmlYFO1SaDeq7sO1BBjy2WTlcCcAnAgm TFiYmU2XblgPt7PsLG0DVkkd =Jv/S -----END PGP SIGNATURE-----

1 0

Symbol visibility patch for GCC v3.4
by Niall Douglas April 5, 2004

April 5, 2004

The following section of this message contains a file attachment prepared for transmission using the Internet MIME message format. If you are using Pegasus Mail, or any other MIME-compliant system, you should be able to save it or view it from within your mailer. If you cannot, please ask your system administrator for assistance. ---- File information ----------- File: GCC3.4-20040324VisibilityPatch.diff Date: 5 Apr 2004, 18:17 Size: 46294 bytes. Type: Unknown

1 0

Loading Boost.Python made bindings is horribly slow?
by Niall Douglas April 5, 2004

April 5, 2004

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 With GCC v3.4 from CVS, I finally have build time down to only nine hours now rather than the 20+ it was with GCC v3.3. However, when loading the bindings into python on Linux v2.4 kernel it takes well over six minutes. Is anyone else having this problem? I don't think it's BPL's fault really as on Windows it only takes a second or two so I'm guessing it's the dynamic linker. I'd imagine that that prebinding linkage feature of newer Linuces will fix this problem - in the meantime, any suggestions? (Here's a thought - GCC outputs far too many symbols into the public ELF table - if GCC had a dllexport/dllimport mechanism like on Windows, the amount of symbols needing to be linked could be reduced very significantly indeed. As it so happens, someone submitted a patch to enable per-class symbol visibility specifications using the same syntax as MSVC, it just needs extending to use a command line argument specified default so you can mark everything default hidden. If people here think this a good idea, I may try tackling it). Cheers, Niall -----BEGIN PGP SIGNATURE----- Version: idw's PGP-Frontend 4.9.6.1 / 9-2003 + PGP 8.0.2 iQA/AwUBQG2bA8EcvDLFGKbPEQKACQCffwTwb5rzU0ikzQ3aWATWRKHirmEAoJez fuxMMJ25M6rhVO6No/2o4OKS =CyW3 -----END PGP SIGNATURE-----

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boost::python::numeric examples?
by Neal D. Becker April 5, 2004

April 5, 2004

I'm trying to learn about using c++ code with python numarray. I wonder if I can find some good tutorial examples?

1 0

Accessing instances of C++ objects in Python - Plus more
by Mike Gonzales April 5, 2004

April 5, 2004

Sorry if I am asking a question that has already been answered; the number of threads in this forum is formidable, and I can only see so far. This question was asking previously by my teammate Adrian Bentley; now that we know more about the problem, hopefully we can get an answer ;). I am working on a game engine that is attempting to use python for scripting support. And unusual requirement of our engine is the necessity of be able to manipulate types in C++ or Python, pretty much at the same time, e.g. dynamically instantiating an entity in C++ and then being able to manipulate it in python, and then updating its status in C++. I won't go into detail on why this is necessary, suffice to say, it has to deal with managing modules at run-time. I am most of the way to acheiving this goal; however, I am having trouble trying to access said C++ objects from python after I have instantiated them. to give you some idea what I am trying to do, following the boost tutorial I have a class that looks sorta like this --------------------------------------------------- struct PythonManager { dict main_namespace; handle<> main_module; //calls PyInitialize, and grabs the main module and namespace PythonManager(); //calls PyFinalize ~PythonManager(); //runs the interpreter on a single expression, and returns the result object EvaluateExpression(std::string &exp); //runs the interpreter on a multiline script void EvaluateScript(std::string &scr); struct PythonWrapper: public PyObject {}; PythonWrapper * MakeDualObject(int sizebytes, PyTypeObject *pto, std::string &varname) { //Get memory from Python and do necessary Python initialization PythonWrapper * mem = (PythonWrapper*)PyObject_Malloc(sizebytes); object obj( handle<>(PyObject_Init(mem, pto))); //put the variable into Python's variable namespace main_namespace[varname.c_str()] = obj; //set up some of my own tracking here.... return mem; } }; ----------------------------------------------------------- Now, the test that I am subjecting myself to see if all of this works is to have one of my defined types that I have extended into Python and another that I have created behind the scenes (like above) play well together. Unfortunately, I haven't gotten that far; so far, I am having trouble trying to get Python to recognize the types that I have just fed it. I successfully have extended a quaternion class in to python, and so I am using that as my test case, even stealing its typeobj * for use in the making these dual-language-objects. ------------------------------------------------------ struct PyQuat: public PyWrapper, public quat {}; //... _PythonManager.EvaluateScript("import mymath"); _PythonManager.EvaluateScript("x = mymath.quat(1,0,0,0)"); object testquat = _PythonManager.EvaluateExpression("x"); //verify that testquat really is a quat. PyWrapper *test = _PythonManager.MakeDualObject(sizeof(PyQuat), testquat.ptr()->objtype, "y"); //now the interpreter goes "boom!" _PythonManager.EvaluateScript("printquat(y)"); -------------------------------------------------------------- So, obviously what I am doing here is probably sub-optimal; still does anybody know of how to pull this off? Even better, if anybody knows of a more elegant way to pull this off, I am all ears. And again, once I pull that off above, I'll need to be able to make a behind-the-scenes-quat and made-in-python-quat play nicely; any advice on how to make that work would be really appreciated. Thanks for your time and patience, Mike Gonzales

3 2

wrapping interfaces and supplied implementations
by Brian Peters April 5, 2004

April 5, 2004

Hello All, I'd like first to thank the Boost.Python team and commend them on their creation. Dave Abrahams et.al. have implemented code the likes of which I could not even have conceived, let alone writen. Boost MPL is not something I could ever have thought up. My hope is simply that someone some day finds my work as useful and impressive as I find theirs. I am trying to wrap a library that implements a generic programming approach to computational geometry and topology. To achieve this it defines a number of interfaces it requires to do its job. For developers who do not wish to code the details of these interfaces it also supplies concrete implementations. Having observed Dave Abrahams' penchant for a working test case I have developed a sandbox representing a portion of the library. It has three classes that are abstract base classes: IFacade, IManager, and IProduct. All their pure virtual methods are defined using raw pointers to abstract base classes. The idea is that an application asks the facade for a manager [ IManager* IFacade::manager() ] and then uses the manager to create products [ IProduct* IManager::create(inti i) ]. The products have state that may be changed by the client or other operations of the facade. The manager can also store and retrieve products. A simple user can use the concrete Manager and Product classes supplied through these interfaces, but a more advanced user could derive their own product and manager from the abc's and pass that into the facade [ void IFacade::setManager(IManager* manager) ]. The old addage applies: "The simple should be easy, but the complex should be possible." i.e use the supplied system if you want, but you can always over ride it with something more complex. So now I want to be able to do the same thing in Python. I want to wrap everything so that a simple user can: * see the abstract base classes in python; i.e. the interfaces, their doc strings, etc. * use the supplied implementation of manager and product * derive their own products and manager if they want/need to in python Well, I got it all working! Not only working, but doing cool python stuff too. Being new to python I have found it interesting that arbitrary attributes and methods can be added to any object regardless of its class. I think of a wrapped Product passed out to python from the supplied Manager class as a python envelope containing the C++ Product. I can scribble on that envelope. Spill coffee on it. Crumple it up a bit. I can store it in the manager and throw it away. When I later retrieve from the manager, not only is it the same C++ Product (i.e same address), but it is the same PyObject (i.e. same address, or "id" as they call it in the interpreter), AND it even has the same note scribbled on it and the coffee stain! Its like decorating C++ classes dynamically at run time. I thought the article about C++/Python integration was cool when I read it a few months ago, but now I really see it. The line between Python and C++ is very fluid. ( http://www.cuj.com/documents/s=8188/cuj0307abrahams ) The code is attached below. For reference I am using the following (admittedly somewhat dated) environment: * Python 2.2.2 * Boost 1.30.0 * Windows NT4 with MSVC6 * RH linux 2.4.2-2 with g++ 1.96 I am offering this example to anyone that finds it useful. It is more complex than the examples I found in the documentation and code, yet still simple enough to examine in detail. I am hoping that those in the know will tell me if I have done anything terribly wrong. I will gladly explain why I have done things the way I have and/or share the verbose version of this sandbox that contains a lot more testing functions and cout's. This message is already too long to do so here. thanks, bfp ====================== > Brian Peters > topology<at>eircom<dot>net =============================================================================== ============ abcdf_ext.cpp ==================================================== #include <boost/python.hpp> #include <iostream> #include <sstream> using namespace boost::python; // --- component code ----------------------------------------------- // published interfaces struct IProduct { virtual ~IProduct() {} virtual int value() const = 0; virtual void set(int i) = 0; virtual int other(IProduct* product) const = 0; }; struct IManager { virtual ~IManager() {} virtual IProduct* create(int i) = 0; virtual IProduct* modify(IProduct* product) = 0; virtual int store(IProduct* product) = 0; virtual IProduct* retrieve(int index) = 0; }; struct IFacade { static IFacade* instance(); virtual ~IFacade() {} virtual IManager* manager() = 0; virtual void setManager(IManager* manager) = 0; virtual void update(int i) = 0; virtual std::string notice() const = 0; }; // supplied implementation of interfaces. // only exposed through pointers to the above interfaces. #define MANAGER_CAPACITY 10 struct Product : IProduct { Product(int i): _i(i) {} virtual ~Product() {} virtual int value() const { return _i; } virtual void set(int i) { _i = i; } virtual int other(IProduct* product) const { int v = -10; // TODO Should I throw if NULL == product??? if (product) v = product->value(); return _i*1000 + v; } int _i; }; struct Manager : IManager { Manager(): mCount(0) { memset(mProducts, 0, sizeof(mProducts)); } virtual ~Manager() {} virtual IProduct* create(int i) { return new Product(i); } virtual IProduct* modify(IProduct* product) { product->set(2 * product->value()); return product; } virtual int store(IProduct* product) { int index = -1; if (MANAGER_CAPACITY > mCount) { index = mCount; mProducts[mCount++] = product; } return index; } virtual IProduct* retrieve(int index) { IProduct* product = NULL; if (MANAGER_CAPACITY > index) product = mProducts[index]; return product; } int mCount; IProduct* mProducts[MANAGER_CAPACITY]; }; struct Facade : IFacade { Facade(): mManager(new Manager) {} virtual ~Facade() {} virtual IManager* manager() { return mManager; } virtual void setManager(IManager* manager) { // TODO Deleting the old manager will cause trouble if it has // already been sent out to python. How do I want to handle this? //if (mManager) // delete mManager; mManager = manager; } virtual void update(int delta) { // TODO get a product iterator from IManager here. IProduct* product; for (int i=0; i < MANAGER_CAPACITY; i++) { if (NULL != (product = mManager->retrieve(i))) product->set(product->value() + delta); } } virtual std::string notice() const { return "IFacade::notice() message: hello world!"; } IManager* mManager; }; // the singleton IFacade* theFacade = NULL; IFacade* IFacade::instance() { if (NULL == theFacade) theFacade = new Facade(); return theFacade; } // --- B.P.L. wrapper code ------------------------------------------- // rudimentary exception class struct error { error(std::string message): _msg(message) {} std::string const _msg; }; // ProductProxy provides abc methods to pass IProduct* to python. struct ProductProxy : IProduct { ProductProxy(IProduct* product) : mProduct(product) {} virtual ~ProductProxy() {} virtual int value() const { if (!mProduct) throw error("Bad proxy"); return mProduct->value(); } virtual void set(int i) { if (!mProduct) throw error("Bad proxy"); mProduct->set(i); } virtual int other(IProduct* product) const { if (!mProduct) throw error("Bad proxy"); return mProduct->other(product); } // this virtual function is overridden in ProductBase virtual int otherWrap(object& product) const { if (!mProduct) throw error("Bad proxy"); ProductProxy* proxy = arg_from_python<ProductProxy*>(product.ptr())(product.ptr()); return mProduct->other(proxy); } IProduct* mProduct; }; // ProductBase is the heldtype for ProductProxy to let python derive from IProduct. struct ProductBase : ProductProxy { ProductBase(PyObject* pyobject): ProductProxy(NULL), mSelf(pyobject) {} virtual ~ProductBase() {} virtual int value() const { return call_method<int>(mSelf, "value"); } int default_value() const { std::ostringstream msg; msg << mSelf->ob_type->tp_name << " missing implementation of function 'value'"; throw error(msg.str()); } virtual void set(int i) { call_method<void>(mSelf, "set", i); } void default_set(int i) { std::ostringstream msg; msg << mSelf->ob_type->tp_name << " missing implementation of function 'set'"; throw error(msg.str()); } virtual int other(IProduct* product) const { ProductProxy proxy(product); return call_method<int>(mSelf, "other", ptr(&proxy)); } // this virtual function is overridden from ProductProxy virtual int otherWrap(object& product) const { return call_method<int>(mSelf, "other", product); } int default_other(object& product) const { std::ostringstream msg; msg << mSelf->ob_type->tp_name << " missing implementation of function 'other'"; throw error(msg.str()); } PyObject* mSelf; }; // ManagerProxy provides abc methods to pass IManager* to python. struct ManagerProxy : IManager { ManagerProxy(IManager* manager): mManager(manager), mCount(0) {} ManagerProxy(ManagerProxy& manager) : mManager(manager.mManager), mCount(manager.mCount) { for (int i=--mCount; 0 <= i; --i) mProducts[i] = manager.mProducts[i]; } virtual ~ManagerProxy() {} virtual IProduct* create(int i) { if (!mManager) throw error("Bad proxy"); return mManager->create(i); } // this virtual function is overridden in ManagerBase virtual object createWrap(int i) { if (NULL == mManager) throw error("Bad proxy"); return object(ptr(new ProductProxy(mManager->create(i)))); } virtual IProduct* modify(IProduct* product) { if (NULL == mManager) throw error("Bad proxy"); return mManager->modify(product); } // this virtual function is overridden in ManagerBase virtual object modifyWrap(object& product) { if (NULL == mManager) throw error("Bad proxy"); ProductProxy* proxy = arg_from_python<ProductProxy*>(product.ptr())(product.ptr()); mManager->modify(proxy); return product; // IManager::modify returns its argument, but if another function might not, do this: //IProduct* value = mManager->anotherFunction(proxy); //return value == proxy ? product : object(ptr(new ProductProxy(value))); } virtual int store(IProduct* product) { return mManager->store(product); } virtual int storeWrap(object& product) { ProductProxy* proxy = arg_from_python<ProductProxy*>(product.ptr())(product.ptr()); // make sure side effects will happen mManager->store(proxy->mProduct); int index = -1; if (MANAGER_CAPACITY > mCount) { index = mCount; mProducts[mCount++] = product; } return index; } virtual IProduct* retrieve(int index) { return mManager->retrieve(index); } virtual object retrieveWrap(int index) { // make sure side effects will happen mManager->retrieve(index); if (MANAGER_CAPACITY > index) return mProducts[index]; else return object(); // python's None } IManager* mManager; // just mirror the Manager approach to storage for sandbox int mCount; object mProducts[MANAGER_CAPACITY]; }; // ManagerBase is the heldtype for ManagerProxy to let python derive from IManager. struct ManagerBase : ManagerProxy { ManagerBase(PyObject* pyobject): ManagerProxy(NULL), mSelf(pyobject) {} virtual ~ManagerBase() {} virtual IProduct* create(int i) { object product = call_method<object>(mSelf, "create", i); return arg_from_python<ProductProxy*>(product.ptr())(product.ptr()); } // this virtual function is overridden from ManagerProxy virtual object createWrap(int i) { return call_method<object>(mSelf, "create", i); } object default_create(int i) { std::ostringstream msg; msg << mSelf->ob_type->tp_name << " missing implementation of function 'create'"; throw error(msg.str()); } virtual IProduct* modify(IProduct* product) { ProductProxy proxy(product); return call_method<IProduct*>(mSelf, "modify", ptr(&proxy)); } // this virtual function is overridden from ManagerProxy virtual object modifyWrap(object& product) { return call_method<object>(mSelf, "modify", product); } object default_modify(object& product) { std::ostringstream msg; msg << mSelf->ob_type->tp_name << " missing implementation of function 'modify'"; throw error(msg.str()); } virtual int store(IProduct* product) { ProductProxy proxy(product); return call_method<int>(mSelf, "store", ptr(&proxy)); } virtual int storeWrap(object& product) { return call_method<int>(mSelf, "store", product); } int default_store(object& product) { std::ostringstream msg; msg << mSelf->ob_type->tp_name << " missing implementation of function 'store'"; throw error(msg.str()); } virtual IProduct* retrieve(int index) { object product = call_method<object>(mSelf, "retrieve", index); return arg_from_python<ProductProxy*>(product.ptr())(product.ptr()); } virtual object retrieveWrap(int index) { return call_method<object>(mSelf, "retrieve", index); } object default_retrieve(int index) { std::ostringstream msg; msg << mSelf->ob_type->tp_name << " missing implementation of function 'retrieve'"; throw error(msg.str()); } PyObject* mSelf; }; // after IFacade, but no need to inherit struct FacadeProxy { ~FacadeProxy() {} static FacadeProxy* instance() { return new FacadeProxy(); } object managerWrap() { if (mManager == object()) mManager = object(ptr(new ManagerProxy(IFacade::instance()->manager()))); return mManager; } void setManagerWrap(object manager) { ManagerProxy* proxy = arg_from_python<ManagerProxy*>(manager.ptr())(manager.ptr()); if (NULL != proxy) { mManager = manager; IFacade::instance()->setManager(proxy); } else { std::ostringstream msg; msg << "Object type: " << manager.ptr()->ob_type->tp_name << " not derived from IManager"; throw error(msg.str()); } } void update(int delta) { IFacade::instance()->update(delta); } std::string notice() const { return IFacade::instance()->notice(); } object mManager; }; // exception handling void translate(error const& e) { PyErr_SetString(PyExc_AttributeError, e._msg.c_str()); } // utility functions PyObject* _last; void dumpLast() { std::cout << "dumpLast" << std::endl; std::cout << " last: " << (void*)_last << " [" << (typeid(*_last)).name() << "]" << std::endl; std::cout << " last->ob_refcnt: " << _last->ob_refcnt << std::endl; std::cout << " last->ob_type->tp_name: " << _last->ob_type->tp_name << std::endl; } void dumpPyObject(PyObject* pyobject) { _last = pyobject; // steal for dumpLast std::cout << "dumpPyObject" << std::endl; std::cout << " pyobject: " << (void*)pyobject << " [" << (typeid(*pyobject)).name() << "]" << std::endl; std::cout << " pyobject->ob_refcnt: " << pyobject->ob_refcnt << std::endl; std::cout << " pyobject->ob_type->tp_name: " << pyobject->ob_type->tp_name << std::endl; } void dumpProduct(ProductProxy* proxy) { std::cout << "dumpProduct" << std::endl; std::cout << " proxy: " << (void*)proxy << " [" << (typeid(*proxy)).name() << "]" << std::endl; ProductBase* base = dynamic_cast<ProductBase*>(proxy); if (base) { std::cout << " proxy->mSelf: " << (void*)base->mSelf << " [" << (typeid(*base->mSelf)).name() << "]" << std::endl; std::cout << " proxy->mSelf->ob_refcnt: " << base->mSelf->ob_refcnt << std::endl; std::cout << " proxy->mSelf->ob_type->tp_name: " << base->mSelf->ob_type->tp_name << std::endl; } else { std::cout << " proxy->mProduct: " << (void*)proxy->mProduct << " [" << (typeid(*proxy->mProduct)).name() << "]" << std::endl; } } int useValue_PyObject_ptr(PyObject* product) { return call_method<int>(product, "value"); } int useValue_object_ref(object& product) { return call_method<int>(product.ptr(), "value"); } int useValue_ProductProxy_ptr(ProductProxy* product) { return NULL != product ? product->value() : -1; } ProductProxy* passBack_ProductProxy_ptr(ProductProxy* product) { return product; } object passBack_object(object& product) { ProductProxy* proxy = arg_from_python<ProductProxy*>(product.ptr())(product.ptr()); if (NULL == proxy) return object(); else return product; } BOOST_PYTHON_MODULE(abcdf_ext) { register_exception_translator<error>(&translate); class_<ProductProxy, ProductBase, boost::noncopyable>("IProduct") .def("value", &ProductProxy::value, &ProductBase::default_value, "Returns an int value") .def("set", &ProductProxy::set, &ProductBase::default_set, "Sets an int value") .def("other", &ProductProxy::otherWrap, &ProductBase::default_other, "Returns an int value using another IProduct") ; class_<ManagerProxy, ManagerBase, boost::noncopyable>("IManager") .def("create", &ManagerProxy::createWrap, &ManagerBase::default_create) .def("modify", &ManagerProxy::modifyWrap, &ManagerBase::default_modify) .def("store", &ManagerProxy::storeWrap, &ManagerBase::default_store) .def("retrieve", &ManagerProxy::retrieveWrap, &ManagerBase::default_retrieve) ; class_<FacadeProxy>("IFacade", no_init) .def("instance", &FacadeProxy::instance, return_value_policy<manage_new_object>()) // How do I do a singleton? .staticmethod("instance") .def("manager", &FacadeProxy::managerWrap) .def("setManager", &FacadeProxy::setManagerWrap) // ,with_custodian_and_ward<1, 2>()) // I don't think I need this as returning an object keeps track of reference counts. .def("update", &FacadeProxy::update) .def("notice", &FacadeProxy::notice) ; def("dumpLast", &dumpLast); def("dumpPyObject", &dumpPyObject); def("dumpProduct", &dumpProduct); def("useValue_PyObject_ptr", &useValue_PyObject_ptr); def("useValue_object_ref", &useValue_object_ref); def("useValue_ProductProxy_ptr", &useValue_ProductProxy_ptr); def("ProductProxy_ptr_manage_new_object", &passBack_ProductProxy_ptr, return_value_policy<manage_new_object>()); def("ProductProxy_ptr_reference_existing_object", &passBack_ProductProxy_ptr, return_value_policy<reference_existing_object>()); def("Product_as_object", &passBack_object); // no return_value_policy needed } #include "../../../boost_1_30_0/libs/python/test/module_tail.cpp" ============ abcdf_ext.cpp ==================================================== # test abcdf_ext: Abstract Base Class with DeFaults from abcdf_ext import * class Derived(IProduct): def __init__(self, i): IProduct.__init__(self) self.i = i def value(self): return self.i def set(self, i): self.i = i def other(self, product): return self.i*1000 + product.value() def callValue(product): return product.value() def callOther(product, other): return product.other(other) def callSet(product, i): product.set(i) class DManager(IManager): def __init__(self): IManager.__init__(self) self._products = [] def create(self, i): return Derived(i) def modify(self, product): product.set(product.value()*3) return product def store(self, product): index = len(self._products) self._products.append(product) return index def retrieve(self, index): try: return self._products[index] except: return None E=IFacade.instance() M=E.manager() D=DManager() m = M.create(2) n = M.create(3) m._m = "m" n._n = "n" i1 = M.store(m) i2 = M.store(n) i3 = M.store(M.create(4)) M.retrieve(i1)._m d = D.create(4) E.setManager(D) Dr=E.manager() e=Dr.create(5) f=Dr.create(6) e._e = "e" f._f = "f" Dr.store(e) Dr.store(f) =============================================================================== ===============================================================================

2 1

Newbie needs advice for decision.
by Billy Gnosis April 4, 2004

April 4, 2004

Hi I want to extend and more important embed Python in my Programs. 1. What is the best (easiest way) to extend Python with C++ ? Swig or Boost.Python, or is there something easier ? 2. What is the best (easiest way) to embed Python in a C++ Program ? Boost.Python, the Python/C Api, or is there something easier out there ? 3. General Question: I played a little bit wit the high level embedding of the python interpreter in my C++ Program (#include "Python.h", Py_Initialize()...etc.etc...). Can I somehow compile and link everything statically ? Meaning, I have one binary in the end, that already includes all necessary parts of the python interpreter - when I give this file somebody else, this should be enough to run it no installation of the python interpreter necessary, etc... Is this possible ? Cheers, sb

2 1

Re: Virtual member functions cause exception in get_derived_class_object
by David Rostowsky April 2, 2004

April 2, 2004

Attached are the files in question. Thanks for the direction. Im a newbie to these lists. In my original post I was trying to post the minimal that failed, so hence I wanted to give everything in the follow-up. Ill try to find a happier middle ground for future posts. "David Abrahams" <dave(a)boost-consulting.com> wrote in message news:uwu4zvpit.fsf@boost-consulting.com... > > Hi David, > > First of all, please bring Boost.Python questions to the C++-sig: > http://www.boost.org/more/mailing_lists.htm#cplussig > > "David Rostowsky" <davros1(a)covad.net> writes: > > > I have a couple of really simple classes: > > > > class MyBase > > { > > public: > > int x; > > virtual int foo(int new_x) { }; // our derived classes may or may > > not override this function. Coders choice. > > }; > > > > class MyDerived: public MyBase > > { > > public: > > int y; > > MyDerived() { y = 0; }; > > int Get(void) { return y; }; > > void Set(int val) { y = val; }; > > }; > > > > My main goal in life is to create an instance of MyDerived class in > > C++: > > MyDerived my_derived = new MyDerived(); > > > > and then pass the pointer to a Python script where the Python script > > can call any of the public member functions. Yes, I am careful to keep > > the pointer around in the C++ code while the Python script uses it. > > So I expose the class (this may or may not be the source of my > > problems, need help): > > > > BOOST_PYTHON_MODULE(test) > > { > > using namespace boost::python; > > > > class_<MyDerived>("MyDerived") > > .def("Get", &MyDerived::Get) > > .def("Set", &MyDerived::Set) > > ; > > } /* test*/ > > > > My impasse is that the virtual function seems to really give Boost > > hell when Im trying to pass the pointer to the class over to the > > python script. Heres the code snippet for that. > > Please post a complete, minimal, reproducible example. > > > Its the conversion thats just KILLING me. > > Chill, dude. You're still alive. At least someone's sending email > on your behalf ;-) > > > If I comment out the virtual function, everything works perfectly! I > > can pass the pointer over to my script, it calls the public member > > functions, and Im happy. HOWEVER, if I put the virtual function back > > in, the following line of code > > Well you've posted several lines there; can you be specific about > which one you're having problems with? > > > just EXPLODES! > > What does "EXPLODES" mean? Do you get a compilation error, a runtime > error, or something else? > > > // It crashes and burns in make_ptr_instance.cpp, function > > get_derived_class_object() > > boost::python::object my_arg(boost::ref(my_derived)); > > > > // pass the pointer over to the script now. > > int rval = callPython("myTestFunc", "Test String argument from c++", > > my_arg); > > -- > Dave Abrahams > Boost Consulting > www.boost-consulting.com > > _______________________________________________ > Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost > begin 666 test_script.py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a)8W!P3V)J.B B M+ T*(" @("!C<'!/8FHN<')I;G10='(H*0T*(" @("!P<FEN= T*#0H@(" @ M(",@4VAO=R!S=&%T92!O9B!C<'!/8FH-"B @(" @<')I;G0@(E!Y=&AO;CH@ M8W!P3V)J+D=E="@I(&]N(&5N=')Y.B(L(&-P<$]B:BY'970H*0T*#0H@(" @ M(",@0VAA;F=E('-T871E(&]F(&]B:F5C= T*(" @("!C<'!/8FHN4V5T*#DI M#0H-"B @(" @(R!3:&]W('-T871E(&]F(&]B:F5C= T*(" @("!P<FEN=" B M4'ET:&]N.B!C<'!/8FHN1V5T*"D@;VX@97AI=" Z(BP@8W!P3V)J+D=E="@I 6#0H-"B @(" @<F5T=7)N(#DY.2 -"@`` ` end begin 666 code2.cpp M#0HO+R!';&]B86P@;6]D=6QE('!O:6YT97(-"F)O;W-T.CIP>71H;VXZ.FAA M;F1L93P^(&UY7VUO9'5L93L-"@T*8VQA<W,@0F%S93$-"GL-"G!U8FQI8SH- M"@EI;G0@>CL-"@E"87-E,2@I('L@>CT@,3L@?3L-"@EV:7)T=6%L('9O:60@ M3VY+97E5<"AU;G-I9VYE9"!S:&]R="!V:7)T=6%L7VME>2D@>R!].PT*#0I] 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