Mailman 3 March 2016 - Cplusplus-sig

Multiple registration safety and unit testing
by David Sankel April 21, 2016

April 21, 2016

Hello all, I'd like to allow a class to be registered more than once and wanted to get your opinion if this change would be a good idea. 'boost::python::class_' always adds a class to the current scope and registers it in the global registry. The global registry code (particularly the 'insert' function in 'src/converter/registry.cpp') asserts that the class hasn't been registered already. This, of course, prevents multiple registrations of the same type. There is a use case, though, where multiple registrations of the same type is both necessary and safe. Generally, a c++ component which has a 'class_' call may not know the name of the module it will eventually end up in. It would still be desirable to write a unit test for this component. If we write a unit test and put the 'class_' into some dummy module we run into a problem where other unit tests might call 'class_' in another scope. The safety of multiple 'class_' calls stems from always using the same conversion function. Semantically everything is a-okay. I'm proposing to change the precondition of the 'boost::python::converter::registry::insert' function from: The behavior is undefined unless the specified 'type_info' object has not already been registered. to: The behavior is undefined unless the specified 'type_info' object has not already been registered with a semantically different converter Any objections? -- David Sankel

2 3

Building Boost Python Tutorial Linker Errors
by Joey Ortiz March 23, 2016

March 23, 2016

Hello, I have spent the past week trying to build the boost python tutorial, only to be stopped by numerous linker errors. I have posted my question on http://stackoverflow.com/questions/36143494/linker-errors-running-bjam-on-b… My system runs Windows 10, Visual Studio 2015 (msvc 14.0), Anaconda 32bit, Anaconda 64bit, and regular default-installed Python 2.7, and the Boost 1.60.0 libraries (I have tried both 32-bit and 64-bit builds). I first build my Boost libraries in either 32-bit (bootstrap, b2) or 64-bit (bootstrap, b2 address-model=64), using the instructions at http://www.boost.org/doc/libs/1_60_0/more/getting_started/windows.html I then follow the most recent boost.python tutorial at http://www.boost.org/doc/libs/1_60_0/libs/python/doc/html/tutorial/tutorial… (which by the way needs serious work). I have tried combinations of the following build instructions and msvc / python settings. bjam bjam address-model=64 bjam address-model=64 architecture=x86 using msvc : 14.0 ; using msvc : 14.0 : "C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin" ; using msvc ; using python ; using python : 2.7 ; using python : 2.7 : C:/Users/Joey/Anaconda2 ; using python : 2.7 : "C:/Users/Joey/Anaconda2 (32-bit)" ; using python : 2.7 # Version : C:\\Users\\Joey\\Anaconda2\\python.exe # Python Path : C:\\Users\\Joey\\Anaconda2\\include # include path : C:\\Users\\Joey\\Anaconda2\\libs # lib path(s) : <define>BOOST_ALL_NO_LIB=1 ; In any setting, when I run "bjam" I get the following output: Performing configuration checks - 32-bit : yes (cached) - arm : no (cached) - mips1 : no (cached) - power : no (cached) - sparc : no (cached) - x86 : yes (cached) ...found 7 targets... - symlinks supported : yes ...found 1 target... ...updating 1 target... config-cache.write bin\project-cache.jam ...updated 1 target... ...patience... ...patience... ...found 1917 targets... ...updating 9 targets... msvc.link.dll ..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.dll Creating library ..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.lib and object ..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.exp object_protocol.obj : error LNK2001: unresolved external symbol __imp__PyObject_GetAttrString wrapper.obj : error LNK2001: unresolved external symbol __imp__PyObject_GetAttrString numeric.obj : error LNK2001: unresolved external symbol __imp__PyObject_GetAttrString enum.obj : error LNK2001: unresolved external symbol __imp__PyObject_GetAttrString class.obj : error LNK2001: unresolved external symbol __imp__PyObject_GetAttrString function.obj : error LNK2001: unresolved external symbol __imp__PyObject_GetAttrString numeric.obj : error LNK2019: unresolved external symbol __imp__PyCallable_Check referenced in function "bool __cdecl boost::python::numeric::`anonymous namespace'::load(bool)" (?load@?A0xc5ed2080@numeric@python@boost@@YA_N_N@Z) class.obj : error LNK2001: unresolved external symbol __imp__PyCallable_Check function.obj : error LNK2001: unresolved external symbol __imp__PyInt_FromLong function_doc_signature.obj : error LNK2001: unresolved external symbol __imp__PyInt_FromLong numeric.obj : error LNK2001: unresolved external symbol __imp__PyInt_FromLong list.obj : error LNK2001: unresolved external symbol __imp__PyInt_FromLong enum.obj : error LNK2001: unresolved external symbol __imp__PyInt_FromLong class.obj : error LNK2001: unresolved external symbol __imp__PyInt_FromLong numeric.obj : error LNK2019: unresolved external symbol __imp__PyBool_FromLong referenced in function "public: __thiscall boost::python::converter::arg_to_python<bool>::arg_to_python<bool>(bool const &)" (??0?$arg_to_python@_N@converter@python@boost@@QAE@AB_N@Z) class.obj : error LNK2001: unresolved external symbol __imp__PyBool_FromLong numeric.obj : error LNK2019: unresolved external symbol __imp__PyString_FromStringAndSize referenced in function "public: __thiscall boost::python::converter::arg_to_python<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::arg_to_python<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??0?$arg_to_python@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@converter@python@boost@@QAE@ABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) str.obj : error LNK2001: unresolved external symbol __imp__PyString_FromStringAndSize builtin_converters.obj : error LNK2001: unresolved external symbol __imp__PyString_FromStringAndSize function_doc_signature.obj : error LNK2001: unresolved external symbol __imp__PyString_FromStringAndSize numeric.obj : error LNK2019: unresolved external symbol __imp__PyErr_Clear referenced in function "bool __cdecl boost::python::numeric::`anonymous namespace'::load(bool)" (?load@?A0xc5ed2080@numeric@python@boost@@YA_N_N@Z) class.obj : error LNK2001: unresolved external symbol __imp__PyErr_Clear function.obj : error LNK2001: unresolved external symbol __imp__PyErr_Clear object_protocol.obj : error LNK2001: unresolved external symbol __imp__PyErr_Clear function.obj : error LNK2001: unresolved external symbol __imp__PyErr_Format numeric.obj : error LNK2001: unresolved external symbol __imp__PyErr_Format from_python.obj : error LNK2001: unresolved external symbol __imp__PyErr_Format registry.obj : error LNK2001: unresolved external symbol __imp__PyErr_Format class.obj : error LNK2001: unresolved external symbol __imp__PyErr_Format enum.obj : error LNK2001: unresolved external symbol __imp__PyEval_CallFunction class.obj : error LNK2001: unresolved external symbol __imp__PyEval_CallFunction pickle_support.obj : error LNK2001: unresolved external symbol __imp__PyEval_CallFunction stl_iterator.obj : error LNK2001: unresolved external symbol __imp__PyEval_CallFunction numeric.obj : error LNK2001: unresolved external symbol __imp__PyEval_CallFunction list.obj : error LNK2001: unresolved external symbol __imp__PyEval_CallFunction dict.obj : error LNK2001: unresolved external symbol __imp__PyEval_CallFunction str.obj : error LNK2001: unresolved external symbol __imp__PyEval_CallFunction numeric.obj : error LNK2019: unresolved external symbol __imp__PyImport_Import referenced in function "bool __cdecl boost::python::numeric::`anonymous namespace'::load(bool)" (?load@?A0xc5ed2080@numeric@python@boost@@YA_N_N@Z) numeric.obj : error LNK2019: unresolved external symbol __imp__PyObject_IsInstance referenced in function "public: static bool __cdecl boost::python::numeric::aux::array_object_manager_traits::check(struct _object *)" (?check@array_object_manager_traits@aux@numeric@python@boost@@SA_NPAU_object@@@Z) from_python.obj : error LNK2001: unresolved external symbol __imp__PyObject_IsInstance class.obj : error LNK2001: unresolved external symbol __imp__PyObject_IsInstance wrapper.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct import.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct exec.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct function_doc_signature.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct iterator.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct stl_iterator.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct object_protocol.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct object_operators.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct life_support.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct pickle_support.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct module.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct builtin_converters.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct registry.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct enum.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct class.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct function.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct tuple.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct str.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct slice.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct from_python.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct numeric.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct list.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct long.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct dict.obj : error LNK2001: unresolved external symbol __imp___Py_NoneStruct numeric.obj : error LNK2001: unresolved external symbol __imp__PyExc_ImportError list.obj : error LNK2019: unresolved external symbol __imp__PyInt_AsLong referenced in function "public: int __thiscall boost::python::detail::list_base::count(class boost::python::api::object const &)const " (?count@list_base@detail@python@boost@@QBEHABVobject@api@34@@Z) str.obj : error LNK2001: unresolved external symbol __imp__PyInt_AsLong class.obj : error LNK2001: unresolved external symbol __imp__PyInt_AsLong builtin_converters.obj : error LNK2001: unresolved external symbol __imp__PyInt_AsLong list.obj : error LNK2019: unresolved external symbol __imp__PyList_New referenced in function "protected: __thiscall boost::python::detail::list_base::list_base(void)" (??0list_base@detail@python@boost@@IAE@XZ) list.obj : error LNK2019: unresolved external symbol __imp__PyList_Insert referenced in function "public: void __thiscall boost::python::detail::list_base::insert(int,class boost::python::api::object const &)" (?insert@list_base@detail@python@boost@@QAEXHABVobject@api@34@@Z) list.obj : error LNK2019: unresolved external symbol __imp__PyList_Append referenced in function "public: void __thiscall .... ....(too many to put here) .... object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_Add referenced in function "class boost::python::api::object __cdecl boost::python::api::operator+(class boost::python::api::object const &,class boost::python::api::object const &)" (??Hapi@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_Subtract referenced in function "class boost::python::api::object __cdecl boost::python::api::operator-(class boost::python::api::object const &,class boost::python::api::object const &)" (??Gapi@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_Multiply referenced in function "class boost::python::api::object __cdecl boost::python::api::operator*(class boost::python::api::object const &,class boost::python::api::object const &)" (??Dapi@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_Divide referenced in function "class boost::python::api::object __cdecl boost::python::api::operator/(class boost::python::api::object const &,class boost::python::api::object const &)" (??Kapi@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_Remainder referenced in function "class boost::python::api::object __cdecl boost::python::api::operator%(class boost::python::api::object const &,class boost::python::api::object const &)" (??Lapi@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_Lshift referenced in function "class boost::python::api::object __cdecl boost::python::api::operator<<(class boost::python::api::object const &,class boost::python::api::object const &)" (??6api@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_Rshift referenced in function "class boost::python::api::object __cdecl boost::python::api::operator>>(class boost::python::api::object const &,class boost::python::api::object const &)" (??5api@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_And referenced in function "class boost::python::api::object __cdecl boost::python::api::operator&(class boost::python::api::object const &,class boost::python::api::object const &)" (??Iapi@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_Xor referenced in function "class boost::python::api::object __cdecl boost::python::api::operator^(class boost::python::api::object const &,class boost::python::api::object const &)" (??Tapi@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_Or referenced in function "class boost::python::api::object __cdecl boost::python::api::operator|(class boost::python::api::object const &,class boost::python::api::object const &)" (??Uapi@python@boost@@YA?AVobject@012@ABV3012@0@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceAdd referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator+=(class boost::python::api::object &,class boost::python::api::object const &)" (??Yapi@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceSubtract referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator-=(class boost::python::api::object &,class boost::python::api::object const &)" (??Zapi@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceMultiply referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator*=(class boost::python::api::object &,class boost::python::api::object const &)" (??Xapi@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceDivide referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator/=(class boost::python::api::object &,class boost::python::api::object const &)" (??_0api@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceRemainder referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator%=(class boost::python::api::object &,class boost::python::api::object const &)" (??_1api@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceLshift referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator<<=(class boost::python::api::object &,class boost::python::api::object const &)" (??_3api@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceRshift referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator>>=(class boost::python::api::object &,class boost::python::api::object const &)" (??_2api@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceAnd referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator&=(class boost::python::api::object &,class boost::python::api::object const &)" (??_4api@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceXor referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator^=(class boost::python::api::object &,class boost::python::api::object const &)" (??_6api@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) object_operators.obj : error LNK2019: unresolved external symbol __imp__PyNumber_InPlaceOr referenced in function "class boost::python::api::object & __cdecl boost::python::api::operator|=(class boost::python::api::object &,class boost::python::api::object const &)" (??_5api@python@boost@@YAAAVobject@012@AAV3012@ABV3012@@Z) wrapper.obj : error LNK2019: unresolved external symbol __imp__PyDict_GetItemString referenced in function "protected: class boost::python::override __thiscall boost::python::detail::wrapper_base::get_override(char const *,struct _typeobject *)const " (?get_override@wrapper_base@detail@python@boost@@IBE?AVoverride@34@PBDPAU_typeobject@@@Z) wrapper.obj : error LNK2001: unresolved external symbol __imp__PyMethod_Type import.obj : error LNK2019: unresolved external symbol __imp__PyImport_ImportModule referenced in function "class boost::python::api::object __cdecl boost::python::import(class boost::python::str)" (?import@python@boost@@YA?AVobject@api@12@Vstr@12@@Z) exec.obj : error LNK2019: unresolved external symbol __imp__PyFile_FromString referenced in function "class boost::python::api::object __cdecl boost::python::exec_file(class boost::python::str,class boost::python::api::object,class boost::python::api::object)" (?exec_file@python@boost@@YA?AVobject@api@12@Vstr@12@V3412@1@Z) exec.obj : error LNK2019: unresolved external symbol __imp__PyFile_AsFile referenced in function "class boost::python::api::object __cdecl boost::python::exec_file(class boost::python::str,class boost::python::api::object,class boost::python::api::object)" (?exec_file@python@boost@@YA?AVobject@api@12@Vstr@12@V3412@1@Z) exec.obj : error LNK2019: unresolved external symbol __imp__PyRun_StringFlags referenced in function "class boost::python::api::object __cdecl boost::python::eval(class boost::python::str,class boost::python::api::object,class boost::python::api::object)" (?eval@python@boost@@YA?AVobject@api@12@Vstr@12@V3412@1@Z) exec.obj : error LNK2019: unresolved external symbol __imp__PyRun_FileExFlags referenced in function "class boost::python::api::object __cdecl boost::python::exec_file(class boost::python::str,class boost::python::api::object,class boost::python::api::object)" (?exec_file@python@boost@@YA?AVobject@api@12@Vstr@12@V3412@1@Z) exec.obj : error LNK2019: unresolved external symbol __imp__PyEval_GetGlobals referenced in function "class boost::python::api::object __cdecl boost::python::eval(class boost::python::str,class boost::python::api::object,class boost::python::api::object)" (?eval@python@boost@@YA?AVobject@api@12@Vstr@12@V3412@1@Z) C:\Users\Joey\Anaconda2\libs\python27.lib : warning LNK4272: library machine type 'x64' conflicts with target machine type 'X86' ..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.dll : fatal error LNK1120: 135 unresolved externals call "C:\Users\Joey\AppData\Local\Temp\b2_msvc_14.0_vcvarsall_x86.cmd" >nul link /NOLOGO /INCREMENTAL:NO /DLL /DEBUG /MACHINE:X86 /MANIFEST /subsystem:console /out:"..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.dll" /IMPLIB:"..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.lib" /LIBPATH:"C:\Users\Joey\Anaconda2\libs" @"..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.dll.rsp" if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL% ...failed msvc.link.dll ..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.dll ..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.lib ..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.pdb... ...removing ..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.lib ...removing ..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi\boost_python-vc140-mt-gd-1_60.pdb ...skipped <pbin\msvc-14.0\debug\threading-multi>hello_ext.dll for lack of <p..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi>boost_python-vc140-mt-gd-1_60.lib... ...skipped <pbin\msvc-14.0\debug\threading-multi>hello_ext.pdb for lack of <p..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi>boost_python-vc140-mt-gd-1_60.lib... ...skipped <p.>boost_python-vc140-mt-gd-1_60.dll for lack of <p..\..\..\..\bin.v2\libs\python\build\msvc-14.0\debug\threading-multi>boost_python-vc140-mt-gd-1_60.dll... ...skipped <p.>hello_ext.dll for lack of <pbin\msvc-14.0\debug\threading-multi>hello_ext.dll... ...skipped <pbin\hello.test\msvc-14.0\debug\threading-multi>hello for lack of <pbin\msvc-14.0\debug\threading-multi>hello_ext.dll... ...failed updating 3 targets... ...skipped 6 targets... When I run "bjam address-model=64" I instead get Performing configuration checks - 32-bit : yes (cached) - arm : no (cached) - mips1 : no (cached) - power : no (cached) - sparc : no (cached) - x86 : yes (cached) - symlinks supported : no (cached) - junctions supported : yes (cached) - hardlinks supported : yes (cached) ...found 1 target... ...updating 1 target... config-cache.write bin\project-cache.jam ...updated 1 target... ...patience... ...patience... ...found 1924 targets... ...updating 5 targets... msvc.link.dll bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pyd Creating library bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pdb and object bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.exp LINK : fatal error LNK1104: cannot open file 'bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pdb' call "C:\Users\Joey\AppData\Local\Temp\b2_msvc_14.0_vcvarsall_amd64.cmd" >nul link /NOLOGO /INCREMENTAL:NO /DLL /NOENTRY /DEBUG /MACHINE:X64 /MANIFEST /subsystem:console /out:"bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pyd" /IMPLIB:"bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pdb" /LIBPATH:"C:\Users\Joey\Anaconda2\libs" @"bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pyd.rsp" if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL% ...failed msvc.link.dll bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pyd bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pdb bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pdb... ...removing bin\msvc-14.0\debug\address-model-64\threading-multi\hello_ext.pyd ...skipped <p.>hello_ext.pyd for lack of <pbin\msvc-14.0\debug\address-model-64\threading-multi>hello_ext.pyd... ...skipped <pbin\hello.test\msvc-14.0\debug\address-model-64\threading-multi>hello for lack of <pbin\msvc-14.0\debug\address-model-64\threading-multi>hello_ext.pyd... ...failed updating 2 targets... ...skipped 3 targets...

2 1

Module import / type registration performance
by John Loy March 16, 2016

March 16, 2016

Hi Everyone, I recently opened a pull request for a pair of changes to improve the time and memory costs when registering types and I'd like to also solicit feedback from the list. https://github.com/boostorg/python/pull/62 The brief summary is that there are a couple of places in the inheritance registration code that scale as O(N^2). For us, N has become large enough that Boost Python is showing up in our internal performance profiles during module imports. The larger of the two changes (b565ac4) switches the smart_graph structures to use a sparse representation. The original smart_graph behaves nicely when N is small and the graph is dense, but as N becomes large, the cost of initializing the table becomes significant. The sparse representation cuts memory usage from hundreds of megabytes down to tens of kilobytes. The second change (e1d2da5) is for those of us using standard libraries that implement std::list::size() in O(N) time, which results in num_edges on our graph also being in O(N). Adding casts is effectively quadratic due to the repeated calls to num_edges. Combined, these changes save ~400ms of application startup time on a 2.3GHz Haswell Xeon. Let me know if you have any questions or concerns, especially if you have performance targets that might be affected by these changes. John

1 0

variant_adaptor
by Mario Lang March 14, 2016

March 14, 2016

Hi. While I haven't really found a way to get reference semantics (hints appreciated), I have now made my discoveries from https://blind.guru/boost_python-and-boost_variant.html into a handy little utility class. This is the best I was able to figure out regarding integration of boost::python with boost::variant. I was hoping to be able to utilize some sort of custom instance_holder, but it seems the library forces me to declare the C++ type for the object held. This prevents me from using a visitor to create the python object at runtime. I would basically need something that returns a boost::python::object, not a concrete C++ type. I haven't found that in the docs/code so far. The best I could find was to_python_converter, but that (at least to me) seems limited to copy semantics. Any hint on how to improve the helper below is very welcome. Maybe someone finds it useful. There seems to be virtually nothing on the Net about this topic. ---<variant_adaptor.hpp>--- #if !defined(MLANG_PYTHON_VARIANT_ADAPTOR_HPP) #define MLANG_PYTHON_VARIANT_ADAPTOR_HPP #include <boost/python/implicit.hpp> #include <boost/python/object.hpp> #include <boost/python/to_python_converter.hpp> #include <boost/variant.hpp> namespace mlang { namespace python { template<typename Variant> struct variant_adaptor { variant_adaptor() { boost::python::to_python_converter<Variant, variant_adaptor>{}; register_convertibles<Variant>::apply(); } template<typename T> struct register_convertibles; template<typename T> struct register_convertibles<boost::variant<T>> { static void apply() { boost::python::implicitly_convertible<T, Variant>(); } }; template<typename T, typename... Ts> struct register_convertibles<boost::variant<T, Ts...>> { static void apply() { boost::python::implicitly_convertible<T, Variant>(); register_convertibles<boost::variant<Ts...>>::apply(); } }; static PyObject *convert(Variant const &v) { return apply_visitor(to_python{}, v); } struct to_python : boost::static_visitor<PyObject *> { template<typename T> result_type operator()(T const &t) const { return boost::python::incref(boost::python::object(t).ptr()); } }; }; } // namespace python } // namespace mlang #endif // !defined(MLANG_PYTHON_VARIANT_ADAPTOR_HPP) ---<snip>--- A small usage example would be: #include <boost/python/class.hpp> #include <boost/python/def.hpp> #include <boost/python/init.hpp> #include <boost/python/module.hpp> #include <boost/python/object.hpp> #include <boost/python/suite/indexing/vector_indexing_suite.hpp> #include "variant_adaptor.hpp" #include <vector> struct a { int x; }; struct b { std::string y; }; bool operator==(a const &lhs, a const &rhs) { return lhs.x == rhs.x; } bool operator==(b const &lhs, b const &rhs) { return lhs.y == rhs.y; } typedef boost::variant<a, b> variant; typedef std::vector<variant> vector; variant make_variant() { return variant(); } vector make_vector() { return vector{a(), b(), a()}; } BOOST_PYTHON_MODULE(bpva) { using namespace boost::python; // Define classes for all variant member types class_<a>("a", init<a>()).def(init<>()).def_readwrite("x", &a::x); class_<b>("b", init<b>()).def(init<>()).def_readwrite("y", &b::y); mlang::python::variant_adaptor<variant>{}; class_<vector>("vector").def(vector_indexing_suite<vector, true>()); def("make_variant", make_variant); def("make_vector", make_vector); } As described in the blog post above, the resulting Python module does work, but it does not allow to assign to members of a container element. Replacing a container element with a new one does work though. So while the Python behaviour is a bit unexpected, it is likely OKish for most use cases. I wonder if I am * missing an obvious technique to get this right, OR * hitting a fundamental limitation of Boost.Python, OR * hitting a fundamental limitation of value semantics vs. dynamic languages? -- CYa, ⡍⠁⠗⠊⠕

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Trouble building boost with Visual Studio 2010
by David Aldrich March 10, 2016

March 10, 2016

Hi I am trying to build Boost 1.60 with Visual Studio 2010 Professional on Windows 10. I use the command: b2 toolset=msvc-10.0 --with-python link=shared and get the following error: python34.lib(python34.dll) : fatal error LNK1112: module machine type 'x64' conflicts with target machine type 'X86' I guess this means I have a conflict of 32-bit and 64-bit libraries. I want to target 32-bit (X86). Do I need to install a 32-bit version of Python? I wonder if that can co-exist with the current version of Python? Best regards David

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Problem with and fix for automatic pointer registration in Boost.Python 1.60
by Greg Falcon March 8, 2016

March 8, 2016

Boost.Python 1.60 has a bug, introducing an incompatibility from 1.59, and first noted on this mailing list on January 11. What has changed is that a class declaration of the form class_<Foo, shared_ptr<Foo>>("Foo"); will no longer automatically register a converter for the shared_ptr wrapper. This is not an intentional change, but a bug exposed by a change to Boost.MPL. The template metaprogramming in class_metadata.hpp makes assumptions about the types used in Boost.MPL that are no longer true. I have posted a fix to this issue at https://github.com/boostorg/python/pull/59/files, which at least solves the problem for us. This patch, when applied against 1.60, fixes pointer registration. It can also be applied to 1.59 without issue. If someone on this list could take a look at this change, I'd appreciate it. Let me know if you have any questions. Thanks, Greg Falcon

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