Mailman 3 May 2005 - Cplusplus-sig

RE: Wrapper for exception translation
by Gottfried.Ganssauge＠HAUFE.DE April 4, 2006

April 4, 2006

> -----Original Message----- > From: David Abrahams [mailto:dave@boost-consulting.com] > Sent: Monday, December 13, 2004 1:04 PM > To: c++-sig(a)python.org; Gottfried Ganßauge > Subject: Re: Wrapper for exception translation > > > Gottfried Ganßauge wrote: > > Hi Dave, > > > > I digged through the class_<> implementation and I think I > know what I > > must do to implement it. Like you suggested I would add another > > argument to the class_base constructor which is used as > another base > > class for the newly created class. > > Hi Gottfried, Hi Dave, > > I don't know if you're still listening, but today I offered to > implement this patch on the C++-sig (see my other post). > Are you still interested? I am still listening but was buried deeply with work so I even had to abandon the work already invested into this. Nonetheless: Yes - I'm still interested. Cheers, Gottfried P.S.: What second Post? I got 2 Copies of this one. > > > > -- > Dave Abrahams > Boost Consulting > http://www.boost-consulting.com >

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Re: exporting __stdcall methods
by David Abrahams Feb. 11, 2006

Feb. 11, 2006

"John Maddock" <john(a)johnmaddock.co.uk> writes: >> Files like boost/type_traits/detail/is_mem_fun_pointer_tester.hpp >> which are outside the Boost.Python library would need to be enhanced >> to deal with __stdcall, etc. > > Should now be fixed in cvs: provided the changes don't break anything else > of course! Fantastic! Thanks, John! -- Dave Abrahams Boost Consulting www.boost-consulting.com

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Re: [C++-sig] In a C++ extension, how to use a C++ class exported in another extension
by Ralf W. Grosse-Kunstleve July 5, 2005

July 5, 2005

I guess the problem is that wxDC is not wrapped with Boost.Python, but with SWIG. Therefore Boost.Python doesn't know how to extract the wxDC instance (or a reference to the instance) from the Python object. I believe this can be solved in a nice and general (via a custom from_python converter), but first I'd experiment like this (untested): void foo(boost::python::object wxDC_swig_object) { } ... def("foo", foo); Pass your SWIG-wrapped wxDC instance to foo(). This should work in any case, I hope. Once you get this working, develop the body of foo(). I'd look at the SWIG generated code for a wxPython function that accepts a wxDC object as an argument. SWIG uses PyArg_ParseTuple() to get a PyObject*; in foo() you want to use wxDC_swig_object.ptr() to get the same pointer. You have to find out how SWIG extracts the wxDC instance given the PyObject* and emulate this in the body of foo(). From within foo() you can finally call your function expecting a wxDC object. Let us know if you get this far. The next step would be to rewrite foo() as a custom converter. However, it is only worth it if you want to wrap a number of functions with wxDC in the argument list. Otherwise the "thin wrapper" approach above (foo() is the thin wrapper) is the final solution. --- Hua Su <suh(a)mails.tsinghua.edu.cn> wrote: > Hi, > > I'v learnt Boost.Python for two weeks and now encounter some problems :( > > In brief, I can't find the way to use a C++ class, which is exported in > an > > existing extension, in another extension written by myself. > > In detail, I'm writing a paint program with wxPython which is an > > extension for GUI library wxWidgets (wxWindows). I use wxPython to implement > > GUI, and use C++ to implement paint operations. > > ( In my application the paint operations is a bottleneck so I have to > implement > > is in C++ ) > > When painting, I need to pass a pointer of DC from Python to my C++ code. > > The problem is, the class "wxDC" is a real C++ class writen in wxWidgets, > > and is exported in wxPython as Python class "DC", but I need use it in my > > code as C++ class "wxDC". I can't find support from Boost.Python for > > this problem. I have tried to pass pointer "void *" instead, but Boost.Python > > declares it does not support "void *" as argument or return type. > > Could someone give me some example? I work for this problem for days :( > > Thanks for your reply. > > regards, > Clark __________________________________ Yahoo! Mail Mobile Take Yahoo! Mail with you! Check email on your mobile phone. http://mobile.yahoo.com/learn/mail

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Re: [C++-sig] policy in map_indexing_suite for map<X,const Y*>
by Scott McKay May 31, 2005

May 31, 2005

> From: Joel de Guzman <djowel(a)gmail.com> > Subject: Re: [C++-sig] policy in map_indexing_suite for map<X,const > Y*> > Message-ID: <4297A124.5040906(a)boost-consulting.com> > > I'm sorry, but, no, not at the moment. If this is a common use case, > perhaps we should make it a part of the DerivedPolicies? Thoughts? I'll take a stab at adding it as a DerivedPolicy. Not totally sure how to, but doing so will be a good way to learn.

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Re: [C++-sig] Traceback error: Pointer
by Lothar Werzinger May 31, 2005

May 31, 2005

On Tuesday 31 May 2005 10:57, Arunie wrote: > No, it doesn't work either way. The python part itself uses the swig > interface, and relies on other Example files. > The file is executable, but it won't execute. I am sorry, but I do not > understand what you mean by 'check if the x bit is set'. I tried to look it > up online, but no avail. Well, as you said you call ./testExample.py I assumed you are using a Unix system. On these systems scripts can specify the interpreter to use by putting a line like #!pathtointerpreter/interpreter as the FIRST line of the script. If this line is missing or wrong you can NOT execute the script like ./testExample.py you would have to write python ./testExample.py instead. If the script contains the line mentioned, it still has to be marked as executable. This can be achieved by issuing the command chmod +x ./testExample.py on the commandline Lothar -- Lothar Werzinger Dipl.-Ing. Univ. framework & platform architect Xcerla Corporation 275 Tennant Avenue, Suite 202 Morgan Hill, Ca 95037 email: lothar(a)xcerla.com phone: +1-408-776-9018

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Traceback error: Pointer
by Arunie May 31, 2005

May 31, 2005

Hey, I keep running into this error and I can't figure out what it is that's going wrong. I wrote a code for C++, where it basically registers an interface. It's a test for now, so it goes out and gets the interface, registers it, and then unregisters it. Then I wrote a python file that does the same thing, and it uses SWIG to talk to C++ files. All this is done compiling with the Makefile. But when I try to run the python file, I keep getting this error that drives me nuts. I did not include the files generated by the Makefile commands, as they shouldn't be edited (I could be wrong). The original files are as follows : ========================================== // // Example.cpp // #include <iostream> #include "Example.h" ExampleClass::ExampleClass() { std::cout << __PRETTY_FUNCTION__ << "\n"; this->init(); } ExampleClass::~ExampleClass() { std::cout << __PRETTY_FUNCTION__ << "\n"; } void ExampleClass::registerInterface(ExampleInterface* newInterface) { std::cout << __PRETTY_FUNCTION__ << "\n"; this->interface = newInterface; } void ExampleClass::callInterface() { std::cout << __PRETTY_FUNCTION__ << "\n"; if (this->interface) { this->interface->doMe(); } else { std::cout << "no callback currently registered\n"; } } void ExampleClass::unregisterInterface() { std::cout << __PRETTY_FUNCTION__ << "\n"; this->init(); } void ExampleClass::init() { std::cout << __PRETTY_FUNCTION__ << "\n"; this->interface = 0; } ============================================================== =========================== // // Example.h // #ifndef _EXAMPLE_H_ #define _EXAMPLE_H_ class ExampleInterface { public: virtual void doMe() = 0; }; class ExampleClass { public: ExampleClass(); ~ExampleClass(); void registerInterface(ExampleInterface* newInterface); void callInterface(); void unregisterInterface(); private: void init(); private: ExampleInterface* interface; }; #endif ================================================== ======================================================== // // Example.i // //%module("directors=1") Example %module Example %{ #include "Example.h" %} //%feature("director") ExampleInterface; class ExampleInterface { public: virtual void doMe() = 0; }; class ExampleClass { public: ExampleClass(); ~ExampleClass(); void registerInterface(ExampleInterface* newInterface); void callInterface(); void unregisterInterface(); }; ================================================================ ============================================================= // // Makefile // NAME = Example ALL = _${NAME}.so test${NAME} SRCS = ${NAME}.cpp test${NAME}.cpp OBJS = ${SRCS:.cpp=.o} CPP = g++ SRC_CFLAGS = -Wall SWIG_CFLAGS = -fpic -I/usr/include/python2.3 LDFLAGS = -shared all: ${ALL} clean: rm -f ${ALL} ${NAME}_wrap.cpp ${NAME}.py ${NAME}.pyc *.o *.doc *~ test: ${ALL} @echo "Running test${NAME}..." ./test${NAME} @echo @echo "Running test${NAME}.py..." ./test${NAME}.py _${NAME}.so: ${NAME}.o ${NAME}_wrap.o ${CPP} ${LDFLAGS} -o $@ $^ ${OBJS}: %.o: %.cpp ${CPP} ${SRC_CFLAGS} -c -o $@ $< ${NAME}_wrap.o: ${NAME}_wrap.cpp ${CPP} ${SWIG_CFLAGS} -c -o $@ $< ${NAME}_wrap.cpp: ${NAME}.i swig -python -c++ -o $@ $< test${NAME}: %: %.o ${OBJS} ${CPP} -o $@ $^ ============================================================ ================================================================ // // testExample.cpp // #include <iostream> #include "Example.h" class TestInterface : public ExampleInterface { public: void doMe(); }; void TestInterface::doMe() { std::cout << __PRETTY_FUNCTION__ << "\n"; }; int main(int argc, char** argv) { ExampleClass myObject; TestInterface myInterface; myObject.registerInterface(&myInterface); myObject.callInterface(); myObject.unregisterInterface(); } =============================================================== AND OFCOURSE, MY PROBLEM: ============================================================ #!/usr/bin/python import Example class TestInterface(Example.ExampleInterface): def __init__(self): print "TestInterface::__init__()" def doMe(self): print "TestInterface::doMe()" myObject = Example.ExampleClass() myInterface = TestInterface() myObject.registerInterface(myInterface) myObject.callInterface() myObject.unregisterInterface() ================================================================= I run Red Hat Enterprise Linux 3. Python - 2.3.4-14 SWIG - 1.3.21-6 Now I run the command: make all and then the command: make test This is the error I get: ----------------------------------------------------------------------------- Running testExample... ./testExample ExampleClass::ExampleClass() void ExampleClass::init() void ExampleClass::registerInterface(ExampleInterface*) void ExampleClass::callInterface() virtual void TestInterface::doMe() void ExampleClass::unregisterInterface() void ExampleClass::init() ExampleClass::~ExampleClass() Running testExample.py... ./testExample.py make: ./testExample.py: Command not found make: *** [test] Error 127 ----------------------------------------------------------------------------------- And so I figured since ./testExample.py isn't going properly, I run the command: python testExample.py Results are this: ------------------------------------------------------------------------------- ExampleClass::ExampleClass() void ExampleClass::init() TestInterface::__init__() Traceback (most recent call last): File "testExample.py", line 14, in ? myObject.registerInterface(myInterface) File "/root/Originals/Example.py", line 68, in registerInterface def registerInterface(*args): return _Example.ExampleClass_registerInterface(*args) TypeError: Expected a pointer ExampleClass::~ExampleClass() ---------------------------------------------------------------------------------- I checked the file Example.py, but found nothing. I can't figure out where I'm going wrong. Any help would be appreciated.

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callbacks to python
by David King May 28, 2005

May 28, 2005

Hi all: Can you quickly tell me how boost might support calling back from C[++] into python, as described in the Python C API here: http://docs.python.org/ext/callingPython.html Thanks, dk

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policy in map_indexing_suite for map<X,const Y*>
by Scott McKay May 27, 2005

May 27, 2005

Is there a way to override the usage of default_call_policies in the map indexing suite without patching map_indexing_suite? I have a std::map with a const pointer as the data type - so I need to provide an appropriate call policy. Many thanks. Scott ---- Scott McKay Yahoo!

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pyste shared_ptr question
by Grant Goodyear May 26, 2005

May 26, 2005

I'm slowly trying to convert some code that throws around raw pointers to use shared_ptr. My current pyste file looks like: Include("emdata.h") Enum("EMAN::fp_flag", "fundamentals.h") periodogram = Function("EMAN::periodogram", "fundamentals.h") set_policy(periodogram, return_value_policy(manage_new_object)) where periodogram returns an EMData*. So, I went through and changed my C++ code to return a shared_ptr<EMData>, and manually patched my boost.python code to read: def("periodogram", &EMAN::periodogram); // removed return policy register_ptr_to_python< shared_ptr<EMAN::EMData> >(); and the code works beautifully, at least as far as I can tell. What's the magic pyste invocation to do the same thing? I'd like to avoid EMData = Class('EMAN::EMData', 'emdata.h') use_shared_ptr(EMData) because that seems to bring in all of the junk in EMData into this module. Help? Thanks, Grant Goodyear -- Grant Goodyear web: http://www.grantgoodyear.org e-mail: grant(a)grantgoodyear.org

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pyste reports no-policy even if wrapper specified
by Vladimir Sukhoy May 25, 2005

May 25, 2005

I specified a wrapper for a function (class static method in fact), which avoids returning reference, but pyste still reports an error.

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