Mailman 3 February 2003 - Cplusplus-sig

Can ownership of a wrapped C++ object be transferred between python objects?
by Bruce Lowery Feb. 4, 2003

Feb. 4, 2003

Part of an API that I'm wrapping goes something like this: struct A {}; struct B { void insert( A* ); } where B::add() takes ownership of the pointer passed to it. However: a = mod.A() b = mod.B() b.add( a ) del a del b # python interpreter crashes # later due to memory corruption. Even binding the lifetime of 'a' to 'b' via with_custodian_and_ward doesn't prevent the python object 'a' from ultimately trying to delete the object it's pointing to (right? - I tried anyway and didn't see any improvement). Is there a way to accomplish a 'transfer-of-ownership' of a wrapped C++ object? Bruce Lowery __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com

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FW: Converting from SWIG to Boost.Python
by BHELLA,OPINDERJIT (HP-Vancouver,ex1) Feb. 3, 2003

Feb. 3, 2003

In the example below, every function is wrapped with in a Py_BEGIN_ALLOW_THREADS/ Py_END_ALLOW_THREADS macro. This macro allows each function to be able to run in multiple threads in Python. Because Py_END_ALLOW_THREADS must be called to acquire the interpreter lock when the function is completed, the PyEval_RestoreThread(_save); is also called before each catch, if an excepting occurs and we return NULL. Thanks for your help David! "BHELLA,OPINDERJIT (HP-Vancouver,ex1)" < opinderjit.bhella(a)hp.com <mailto:opinderjit.bhella@hp.com>> writes: I have read through the tutorial and was unable > to figure out how to reproduce the > following SWIG logic that uses the Py_BEGIN_ALLOW_THREADS and > Py_END_ALLOW_THREADS macros. > <snip> Can you explain what it does? -- David Abrahams dave(a)boost-consulting.com <mailto:dave@boost-consulting.com> * <http://www.boost-consulting.com> Boost support, enhancements, training, and commercial distribution -----Original Message----- > From: BHELLA,OPINDERJIT (HP-Vancouver,ex1) > Sent: Thursday, January 30, 2003 11:52 AM > To: 'c++-sig(a)python.org' > Subject: Converting from SWIG to Boost.Python > > > Hi, > > I have been using SWIG 1.5p for about a year with good success. However, I > was interested in the newer functionality > that Boost.Python provides. I have read through the tutorial and was > unable to figure out how to reproduce the > following SWIG logic that uses the Py_BEGIN_ALLOW_THREADS and > Py_END_ALLOW_THREADS macros. > > Thanks. > > SWIG example: > %except(python) > { > Py_BEGIN_ALLOW_THREADS > try > { > $function > } > catch(BlackstoneErrorObject &e) > { > PyEval_RestoreThread(_save); > switch(e.getCode()) > { > case SUCCESS: ... break; > case GENERAL_ERROR: break; > default: ...break; > } > return NULL; > } > catch (...) > { > PyEval_RestoreThread(_save); > PyErr_SetString(BlackstoneError,"..."); > return NULL; > } > Py_END_ALLOW_THREADS > }

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(no subject)
by cyril bonnard Feb. 3, 2003

Feb. 3, 2003

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Re: python keyword arguments ?
by David Abrahams Feb. 2, 2003

Feb. 2, 2003

Alex, Please in the future post your Boost.Python questions to the C++-sig: http://mail.python.org/mailman/listinfo/c++-sig "Alex le grand" <alex(a)glumol.com> writes: > hi I saw on the index page of the boost.python > documentation that version V2 now has support for the > python "keyword arguments" but I can't find any > documentation about it. Is there any documentation or > examples about wrapping the python keyword arguments > function into C++ ? The information you need is in the reference documentation for def(). Please see: http://www.boost.org/libs/python/doc/v2/def.html#def-spec -- David Abrahams dave(a)boost-consulting.com * http://www.boost-consulting.com Boost support, enhancements, training, and commercial distribution

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Docstring for overloaded method
by Achim Domma Feb. 1, 2003

Feb. 1, 2003

Hi, I have something like class_<MyClass>("MyClass") .def("myFkt", (overloaded1)&MyClass::myFkt) .def("myFkt", (overloaded2)&MyClass::myFkt) ....; where overloaded1 and overloaded2 are the different signatures for the overloads. Now I want to specify a docstring for myFkt. Where should I do that? On the first version, on the last or on both? regards, Achim

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