- Boost-users - lists.preview.boost.org

newbie: need example (call python from c++)
by Peter Piehler 04 Jul '04

04 Jul '04

Hello, I use call<void>(pyFunc,arg1,..) to call a python function with standard double, int etc. What must I do to call a function with a c++ object as argument? psydocode: class MyAnimal { /*...*/ std::string __strName; public: MyAnimal() : __strName("Tux") {} /*...*/ std::string getName() { return __strName;} void setName(const std::string &strName) { __strName = strName; } }; int main() { /*...*/ MyAnimal* pTux = new Animal; /*do something with pTux*/ /*use a python function with pTux*/ call<void>(pyFunc1, ?pTux? ); /*change attributes pTux in pyFunc2*/ dog = call<MyAnimal>(pyFunc2, ?pTux?); /*if it possible to call by reference?*/ call<void>(pyFunc3, ?pTux?); pTux->getName();// return Cat } python module: def py_func1(a): print a.getName() def py_func2(a): a.setName('Dog') return a def py_funnc3(a): a.setName('Cat') ___________________________________________________________ Gesendet von Yahoo! Mail - Jetzt mit 100MB Speicher kostenlos - Hier anmelden: http://mail.yahoo.de

2 1

Problem with boost random library.
by Joshua Little 04 Jul '04

04 Jul '04

Hi all, I'm trying to use the randome number generators but I am having some problems. I'm using boost 1.31.0 and gcc 3.2 on Windows 2000. Here is my code : printf(" Die \n "); //std::cout << "Die Rolls" << std::endl; try { boost::mt19937 rng; // produces randomness out of thin air // see pseudo-random number generators boost::uniform_int<> six(1,6); // distribution that maps to 1..6 // see random number distributions boost::variate_generator<boost::mt19937, boost::uniform_int<> > die(rng, six); // glues randomness with mapping int x = die(); printf(" Die %d\n ",x); } catch(...) { std::cout << "exception" << std::endl; printf(" Die exception \n "); } I basically copied the example code off the web site to see if I could get it to work but I'm not having any luck. If I have the variate_generator defined as above I do not not get any output to the console after the declaration of die. I tried printf's and stream output but neither works, I never see the "Die %d" printed out and I do not see either of the outputs in the catch(...) section. printed either. I even had a throw in the try block at one time to see if it could get to the catch section and did not see output. When I remove the die declaration (and comment out the code that uses it) but leave the generator and the distribution then I can see output again and if I throw after the distribution declaration then I see both output statements in the catch block. So it seems like if I have the variate generator declared then I can't see any output after that, but when I comment it out I can see output again. I'm not sure what I'm doing wrong since I am basically copying a pretty simple example from the book I just can't get it to work. Ah and just incase this makes a difference I'm running this code as a test case in a boost test suite. I wanted to try to get it to work there before putting it into my main app. Thanks, Joshua.

2 5

building boost program options
by Christopher Baus 03 Jul '04

03 Jul '04

I'm trying to build the boost sandbox project program_options and am failing. Anyone know what version of boost is compiles cleanly with? -- Christopher Baus http://www.baus.net/

3 2

RE: [Boost-users] Re: boost test doesn't track validation outside autofunctions
by Rozental, Gennadiy 02 Jul '04

02 Jul '04

> > > void validate(X args) { > > > if (some tests) > > > BOOST_ERROR("message"); > > > } > > > BOOST_AUTO_UNIT_TEST(testfunction) { > > > // set up arguments > > > validate(args) > > > } [...] > I think the problem is a think-o on my part. > In the pseudo-code above, BOOST_ERROR is not executed unless > "some tests" is true. So if the tests are OK, BOOST_ERROR is > never hit. > > I think the report of 0 (boost) tests being run is therefore > accurate, though confusing. It should actually say that 1 test cases being run, but no assertions executed. > Does that sound right? > > Is there a way to signal to boost that you are doing a test, > without the error? You have 2 choices. 1. Rewrite your test, so that it looks like: ... BOOST_CHECK_MESSAGE( some_test, "message" ); 2. Or you could write it like this: .... If(some_test) BOOST_ERROR("message") else BOOST_MESSAGE( "no error" ); I prefer first solution usually. HTH, Gennadiy

2 1

boost test doesn't track validation outside auto functions
by Ross Boylan 02 Jul '04

02 Jul '04

I have a test program that looks like this, in stylized form: -------------------------- #include <boost/test/auto_unit_test.hpp> using namespace boost::unit_test_framework; void validate(X args) { if (some tests) BOOST_ERROR("message"); } BOOST_AUTO_UNIT_TEST(testfunction) { // set up arguments validate(args) } ---------------------------------- When I run this with report-level detailed, it reports that there are 0 assertions in testfunction. Furthermore, the assertions done in validate are not even added to the overall number of assertions reported for the run. I know the checks are being run, because I have seen errors from them. Also, the error messages include the name "testfunction", so it is available at run time. It would be nice if the error reporting and logging functions got their info at run-time; apparently they are grabbing it from some pre-processor magic at the moment (I haven't examined the code in detail; that's just an inference from the behavior). Since the tests do seem to be run, this is basically a cosmetic problem, but it would be nice to fix. If any easy fixes occur to anyone, I'd love to know. Boost 1.31.0 on Debian. P.S. The module's author is listed as rogeeff(a)fusemail.com in the documentation, but that address doesn't work. -- Ross Boylan wk: (415) 502-4031 530 Parnassus Avenue (Library) rm 115-4 ross(a)biostat.ucsf.edu Dept of Epidemiology and Biostatistics fax: (415) 476-9856 University of California, San Francisco San Francisco, CA 94143-0840 hm: (415) 550-1062

2 2

Sun Solaris Forte 8 and boost_1_31_0
by Tom Aratari 02 Jul '04

02 Jul '04

Hello, Has anyone gotten boost_1_31 to compile with Forte 8.0 (__SUNPRO_CC = x550) ? I get errors for the boost::iterator. Also, does anyone know if the next release of boost will be compatible with forte 8.0? Thanks Tom

5 4

Boost Test Tutorial
by Sebastian Stein 02 Jul '04

02 Jul '04

I have written a small tutorial how to use boost test within the KDE project. If you are interested, you will find it under: http://www.hpfsc.de/boosttest/ Sebastian -- http://www.hpfsc.de/ - die Seite rund um: Assembler, Bundeswehr, TFT LCDs, Halle/Saale, Fahrradtouren, Neuseeland, Wanderstaat Mauma, Raumschiff USS Nathan, Enemy Room, MLCAD Tutorial

1 0

standard way to specify undefined values
by Erik Thiele 02 Jul '04

02 Jul '04

hi, i have a userdefined type "foobar". it has a special value that means "undefined". is there a standard way to specify which value is undefined? i do not want to use boost::optional here, as foobar itself can be "undefined". you know: class foobar { static const foobar undefined(blablabla); int a,b,c; } but is this "standard"? cya erik -- Erik Thiele

1 0

RE: [Boost-users] Re: [mpl] Alexandrescu's hierarchy generators
by Klaus Nowikow 02 Jul '04

02 Jul '04

David Abrahams wrote: > [..] > template<class T, class Base> > struct node; > > typedef mpl::vector<int, char, long> types; > > // node<int, node<char, node<long, mpl::empty_base> > > > typedef mpl::inherit_linearly< > types > , node<_2,_1> > >::type lin; > [...] > HTH. That helps a lot. Thank you! -- Klaus Nowikow

1 0

iterator_adaptor problem (mpl?)
by Angus Leeming 01 Jul '04

01 Jul '04

Consider a container such as std::vector<std::pair<int, std::string> > my_container; I want to be able to iterate over the ints of this container so, following the tutorial to the iterator_adaptor docs, came up with template <typename BaseIterator> class first_iter : public boost::iterator_adaptor< first_iter<BaseIterator>, BaseIterator, boost::use_default, boost::use_default, typename BaseIterator::value_type::first_type & > { // snip body }; This works fine so long as BaseIterator::value_type is not const, but falls over when it is because I've defined the 'super_t::reference' type to be mutable. I guess that I need a piece of metafunction magic, but my naive implementation fails typename boost::mpl::apply_if< boost::is_const<typename BaseIterator::value_type> , typename BaseIterator::value_type::first_type const & , typename BaseIterator::value_type::first_type & >::type trial.C:38: error: no type named `type' in `struct boost::mpl::apply_if< boost::is_const<std::pair<int, std::string> >, const int&, int&>' I must admit I'm a bit baffled. There plainly is a 'type' in the apply_if class template. Any pointers? I attach the code as I have it. While I'm at it, is there not something in the MPL that will return the appropriate const-qualified reference for me? None of the header file names in boost/mpl jump out and grab me, but I may well be looking in the wrong place. Regards, Angus

2 4