Mailman 3 October 2005 - Cplusplus-sig

Can QPointer be used as a smart pointer?
by Eric Jardim Oct. 21, 2005

Oct. 21, 2005

Hi, The Qt4 library have a custom smart pointer type template, QPointer<...>: http://doc.trolltech.com/4.0/qt4-intro.html#qpointer-t http://doc.trolltech.com/4.0/qpointer.html Is it compatible with boost.python, like smart_ptr and auto_ptr are, or do I have to register (if possible) it? Thanks, [Eric Jardim]

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cross compile python for embedded system
by giovanniangeli＠iquattrocastelli.it Oct. 21, 2005

Oct. 21, 2005

thank you Stefan, I think that the difficulties arising in the cross-compilation procedure come essentially from the intricated sequence of configuration operations specific of the python package, hence someone who knows the details of the configure procedure performed by the automatic configure utility used in building Python could address me toward a solution. regards, Giovanni. Stefan Seefeld seefeld at sympatico.ca wrote: > giovanniangeli at iquattrocastelli.it wrote: > > how can I cross-compile python for a Linux target (arm9 based) system, on > > a > > Linux host PC, using the cross gnu tool chain ? > > If you are asking about compiling Python itself (as opposed to > boost.python), > you should direct your question at a gcc-related mailing list such as > gcc-help at gcc.gnu.org instead. > Regards, > Stefan

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Re: [C++-sig] Beginner Question on Pointers Passed to Python via Boost
by Matthew B. Keyes Oct. 19, 2005

Oct. 19, 2005

One quick note: If I use a return_value_policy of reference_existing_object, it seems to work. I know this is considered "dangerous" - would this be problematic in this case? Thanks again! "Matt" <mjkeyes(a)sbcglobal.net> wrote in message news:<dj6bk6$960$1(a)sea.gmane.org>... > Hello again, > > To start with, let me provide a simple case scenario to elaborate on what I > want to do: > > class UserData > { > public: > UserData() : m_nID(0) {} > virtual ~UserData() {} > > int GetID() {return m_nID;} > void SetID(int nID) {m_nID = nID;} > > protected: > int m_nID; > }; > > class UserDataMgr > { > public: > UserDataMgr() {} > virtual ~UserDataMgr() {DeleteMappedUserData();} > > void RegisterUserData(int nID) > { > //do some checking to see if it already exists... left out for > simplicity > > UserData *pData = new UserData(); > pData->SetID(nID); > m_MappedUserData[nID] = pData; > } > > UserData * GetUserData(int nID) > { > return m_MappedUserData[nID]; > } > > protected: > void DeleteMappedUserData() > { > //iterate through the map and delete the pointers... > } > > std::map<int,UserData*> m_MappedUserData; > } > > BOOST_INIT_MODULE(MyModule) > { > class_<UserData, boost::noncopyable>("UserData") > .def("GetID",&UserData::GetID) > ; > > class_<UserDataMgr>("UserDataMgr") > //If I understand things correctly, the below will cause Python to > manage the lifetime of the UserData * returned > .def("GetUserData", &UserDataMgr::GetUserData, > return_value_policy<manage_new_object>())) > ; > } > > What I'm hoping to accomplish is the above scenario *without* letting Python > manage the lifetime of the UserData pointer. In other words, I want to be > able to have a single copy of a UserData instance available in which Python > can retrieve from the UserDataMgr and perform operations on (but not destroy > or copy the underlying pointer). Is this possible? I'm sure this is a > beginner question, but help is appreciated. > > Note - I imagine that the manage_new_object return policy will be changed, > but I'm simply supplying what I have for illustration. > > Thanks!

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Beginner Question on Pointers Passed to Python via Boost
by Matt Oct. 19, 2005

Oct. 19, 2005

Hello again, To start with, let me provide a simple case scenario to elaborate on what I want to do: class UserData { public: UserData() : m_nID(0) {} virtual ~UserData() {} int GetID() {return m_nID;} void SetID(int nID) {m_nID = nID;} protected: int m_nID; }; class UserDataMgr { public: UserDataMgr() {} virtual ~UserDataMgr() {DeleteMappedUserData();} void RegisterUserData(int nID) { //do some checking to see if it already exists... left out for simplicity UserData *pData = new UserData(); pData->SetID(nID); m_MappedUserData[nID] = pData; } UserData * GetUserData(int nID) { return m_MappedUserData[nID]; } protected: void DeleteMappedUserData() { //iterate through the map and delete the pointers... } std::map<int,UserData*> m_MappedUserData; } BOOST_INIT_MODULE(MyModule) { class_<UserData, boost::noncopyable>("UserData") .def("GetID",&UserData::GetID) ; class_<UserDataMgr>("UserDataMgr") //If I understand things correctly, the below will cause Python to manage the lifetime of the UserData * returned .def("GetUserData", &UserDataMgr::GetUserData, return_value_policy<manage_new_object>())) ; } What I'm hoping to accomplish is the above scenario *without* letting Python manage the lifetime of the UserData pointer. In other words, I want to be able to have a single copy of a UserData instance available in which Python can retrieve from the UserDataMgr and perform operations on (but not destroy or copy the underlying pointer). Is this possible? I'm sure this is a beginner question, but help is appreciated. Note - I imagine that the manage_new_object return policy will be changed, but I'm simply supplying what I have for illustration. Thanks!

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cross compile python for embedded system
by giovanniangeli＠iquattrocastelli.it Oct. 19, 2005

Oct. 19, 2005

how can I cross-compile python for a Linux target (arm9 based) system, on a Linux host PC, using the cross gnu tool chain ? Thank you. Giovanni.

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Re: [C++-sig] Nasty Heap Error in MSVC 7.1 WithBoost andPythonUsing Derived Classes
by mjkeyes＠sbcglobal.net Oct. 19, 2005

Oct. 19, 2005

I thought that at first, too. I've done a search on my entire computer for every boost_python* file there is and deleted them, but the error remains after I build again with bjam. I'm going to look into it a bit further tonight and see if I can find any other differences. Thanks for all the help guys. "David Abrahams" <dave(a)boost-consulting.com> wrote in message news:<ull0qij2v.fsf(a)boost-consulting.com>... > "Matthew B. Keyes" <Keyes(a)simcrest.com> writes: > > > Here is how I built my extension/embedded application and extension > > dll with MS Visual Studio .NET 2003: > > > > -Use the MSVC project supplied with Boost.Python to build > > boost_python.dll -Link to the boost_python.lib file for both > > projects -Build (and everything works fine and runs well) > > > > Now, in trying to add the import function, I retrieved the latest > > Boost files from CVS. I initially tried to use the supplied MSVC > > project to build the boost_python.dll, but I received linking errors > > when I use the import function. Thus, I fired up bjam and let it > > build the boost_python.dll file. However, when I rebuild my project > > that uses import (the extension/embedded application), I still > > receive the linking error. If I add import.cpp to the project, the > > linking error goes away. > > > > I tried looking at the exec.cpp test applet via bjam, but I receive > > several errors on some of the other applets and it is very difficult > > to filter out all the command line chatter to see what happened with > > the exec applet. That said, I do take your word for it that it > > works. > > > > The specific linking error I receive is this: > > > > error LNK2019: unresolved external symbol "class > > boost::python::api::object __cdecl boost::python::import(class > > boost::python::str)" > > (?import@python@boost@@YA?AVobject@api@12@Vstr@12@@Z) referenced in > > function "public: virtual bool __thiscall > > PythonLib::PythonLibObjectContainer::CreateInstanceOfObject(class > > std::basic_string<char,struct std::char_traits<char>,class > > std::allocator<char> > const &,class std::basic_string<char,struct > > std::char_traits<char>,class std::allocator<char> > const &)" > > (?CreateInstanceOfObject@PythonLibObjectContainer@PythonLib@@UAE_NAB > > V?$b > > asic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@0@Z) > > Then you're clearly linking with the old library you built with the > IDE and not the one you built with bjam. > > -- > Dave Abrahams > Boost Consulting > www.boost-consulting.com

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Re: [C++-sig] Nasty Heap Error in MSVC 7.1 With Boost andPythonUsing Derived Classes
by Matthew B. Keyes Oct. 18, 2005

Oct. 18, 2005

Here is how I built my extension/embedded application and extension dll with MS Visual Studio .NET 2003: -Use the MSVC project supplied with Boost.Python to build boost_python.dll -Link to the boost_python.lib file for both projects -Build (and everything works fine and runs well) Now, in trying to add the import function, I retrieved the latest Boost files from CVS. I initially tried to use the supplied MSVC project to build the boost_python.dll, but I received linking errors when I use the import function. Thus, I fired up bjam and let it build the boost_python.dll file. However, when I rebuild my project that uses import (the extension/embedded application), I still receive the linking error. If I add import.cpp to the project, the linking error goes away. I tried looking at the exec.cpp test applet via bjam, but I receive several errors on some of the other applets and it is very difficult to filter out all the command line chatter to see what happened with the exec applet. That said, I do take your word for it that it works. The specific linking error I receive is this: error LNK2019: unresolved external symbol "class boost::python::api::object __cdecl boost::python::import(class boost::python::str)" (?import@python@boost@@YA?AVobject@api@12@Vstr@12@@Z) referenced in function "public: virtual bool __thiscall PythonLib::PythonLibObjectContainer::CreateInstanceOfObject(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?CreateInstanceOfObject@PythonLibObjectContainer@PythonLib@@UAE_NABV?$b asic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@0@Z) PythonLib::PythonLibObjectContainer is a class I have to persist a Boost.Python object after the function call (it basically maps an extracted pointer to its object until the object is no longer needed). Not that that part is important, but I thought I'd clarify as to what is being stated on the error above. Like I said, I can include import.cpp into the project and it builds fine. That solution works, but it is not as desirable as leaving all the Boost.Python files out and simply including the .hpp files. Thanks for any additional help. "Stefan Seefeld" <seefeld(a)sympatico.ca> wrote in message news:<43550C0E.8000508(a)sympatico.ca>... > mjkeyes(a)sbcglobal.net wrote: > > Sorry for the spam, but one final note: > > > > I used bjam and still got the linking error. If I add import.cpp to my > > project, the linking error goes away. Thoughts? I looked at the build > > files and see that exec.cpp and import.cpp have been added, but I'm > > still getting this linking error. > > Sorry, that's still too vague to be of any help. The 'exec.cpp' test applet, > which makes use of both, exec as well as import, gets built and run with bb1, > and there are no linking errors on any of the tested platforms. > > I thus have no idea what could be the cause of the failure you are seeing. > It's most probably related to your build procedure. (But since I don't have > MSVC I'm totally unqualified to help if the problem is related to that.) > > Regards, > Stefan

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Re: [C++-sig] Nasty Heap Error in MSVC 7.1 With Boost andPythonUsing Derived Classes
by mjkeyes＠sbcglobal.net Oct. 18, 2005

Oct. 18, 2005

Sorry for the spam, but one final note: I used bjam and still got the linking error. If I add import.cpp to my project, the linking error goes away. Thoughts? I looked at the build files and see that exec.cpp and import.cpp have been added, but I'm still getting this linking error. <mjkeyes(a)sbcglobal.net> wrote in message news:<000001c5d3a2$f7e1f2f0$210110ac@CROW>... > One more note - I'm using the Visual Studio project included in the > Boost folders for Python. Import.cpp was not part of this project - I > added it, but I'm still getting the linking problems. > > "David Abrahams" <dave(a)boost-consulting.com> wrote in message > news:<ur7aqdcmi.fsf(a)boost-consulting.com>... > > "Matt" <mjkeyes(a)sbcglobal.net> writes: > > > > > Hey all, > > > > > > i'm trying to create an application that both embeds and extends > > > python through boost. i've got a rough framework up and running, > > > but now that i'm finally to the python part i'm having troubles. > > > Please know that i'm a noob to boost and to boost.python, so if you > > > see any obvious noob idiocies in my code please point them out > > > (we've all got to start learning somewhere :)). > > > > You should never be doing any Py_XINCREF or Py_XDECREF stuff when > > using Boost.Python. Also, you're using an outdated approach to > > supporting virtual functions. > > > > I suggest you follow the example of > > http://www.boost-consulting.com/boost/libs/python/test/exec.cpp > > > > You'll need the latest Boost CVS state in order to use all the > > idioms > > therein, though. > > > > -- > > Dave Abrahams > > Boost Consulting > > www.boost-consulting.com

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Issues with Overloading with Boost
by Dirgesh Patel Oct. 18, 2005

Oct. 18, 2005

I have listed many questions about overloading in the gmane.comp.python.c++ newsgroup. Yet i still have not found a cure for my issue. The problem that I am having is I have a function called bkimage* copy(bkimage *img, xint32_t pln0, xint32_t row0, xint32_t col0, xint32_t pln1, xint32_t row1, xint32_t col1) then i have a boost.cpp file which is running this line BOOST_PYTHON_FUNCTION_OVERLOADS(imageMorph_copy, copy, 1, 7) and def("copy", copy, imageMorph_copy() [return_value_policy<manage_new_object>()] ); yet i still get errors

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Re: [C++-sig] Nasty Heap Error in MSVC 7.1 With Boost and PythonUsing Derived Classes
by mjkeyes＠sbcglobal.net Oct. 18, 2005

Oct. 18, 2005

One more note - I'm using the Visual Studio project included in the Boost folders for Python. Import.cpp was not part of this project - I added it, but I'm still getting the linking problems. "David Abrahams" <dave(a)boost-consulting.com> wrote in message news:<ur7aqdcmi.fsf(a)boost-consulting.com>... > "Matt" <mjkeyes(a)sbcglobal.net> writes: > > > Hey all, > > > > i'm trying to create an application that both embeds and extends > > python through boost. i've got a rough framework up and running, > > but now that i'm finally to the python part i'm having troubles. > > Please know that i'm a noob to boost and to boost.python, so if you > > see any obvious noob idiocies in my code please point them out > > (we've all got to start learning somewhere :)). > > You should never be doing any Py_XINCREF or Py_XDECREF stuff when > using Boost.Python. Also, you're using an outdated approach to > supporting virtual functions. > > I suggest you follow the example of > http://www.boost-consulting.com/boost/libs/python/test/exec.cpp > > You'll need the latest Boost CVS state in order to use all the idioms > therein, though. > > -- > Dave Abrahams > Boost Consulting > www.boost-consulting.com

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