- Boost-users - lists.boost.org

Re: [Boost-users] port of GameDev SDL lib in Boost?
by Christian Henning 07 Jun '07

07 Jun '07

Fanzhe, I have been working on a sdl wrapper for boost::gil. It lets you draw on a canvas and react to event such as a timer event. I was thinking of outsourcing this portion so people can use just that. The good thing is the sdl is supporting almost the same platforms as boost does. The bad thing probably is the license sdl is using, LGPL. If you want I can give you a pointer for the code. Christian On 6/6/07, fanzhe cui <fanzhe.cui(a)goldiom.com> wrote: > Yes, I was referring to that library and more info could be found from the > web: http://www.libsdl.org/. > The problem with the boost timer that you mentioned is that it provides the > time elapsed, but not the interface like provided by SDL lib. Particularly > the kind of timer callback function that is available in SDL lib is not > available in Boost lit. > > Best regards, > Fanzhe Cui > > ++++++++++++++++++++++ > Goldiom Systems LLC > - Information and Communication Technology Provider > Email: fanzhe.cui(a)goldiom.com > Tel: 973-210-4254 > www.goldiom.com > > -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Tarjei Knapstad > Sent: Wednesday, June 06, 2007 4:02 AM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] port of GameDev SDL lib in Boost? > > On 6/6/07, fanzhe cui <fanzhe.cui(a)goldiom.com> wrote: > > I have been using both Boost lib and GameDev SDL lib in same projects. > Both > > of the lib have very good platform independency. But they have some > > functionalities overlapping each other and I would like to use only one of > > them. The timer lib in GameDev SDL is very easy to use and I hope such lib > > or functionally similar one exists in Boost lib. I had a look at boost > > archive on previous discussion on implementing Boost timers and feel that > > there is still no good implementation of timer in Boost lib (correct me if > I > > am wrong). Anybody in this email list had a look at GameDev timer and have > > considered implementing such a lib in Boost? > > > > Are you referring to the Simple Direct Medialayer? > > http://lazyfoo.net/SDL_tutorials/lesson12/index.php > > What's wrong with/missing in boost::timer ? > > http://boost.org/libs/timer/index.html > > -- > Tarjei > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

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Uninitialized value p$m_value
by Paul 07 Jun '07

07 Jun '07

Hi, I'm trying to learn how to use the Boost Graph Library. Here is a very simple code example. #include <boost/graph/adjacency_list.hpp> #include <string> int main( void ) { using namespace std; using namespace boost; typedef adjacency_list< listS, vecS, directedS, // Vertex properties property< vertex_name_t, std::string >, // Edge properties property< edge_weight_t, int > > Graph; Graph graph; // Graph traits used to access graph's iterator types graph_traits< Graph >::vertex_descriptor a, b; a = add_vertex( graph ); b = add_vertex( graph ); graph_traits< Graph >::edge_descriptor ed; bool inserted; tie( ed, inserted ) = add_edge( a, b, graph ); // LINE 26 return 0; } When I compile this with g++ v4, I get on my Debian Etch system the warning for line 26: /usr/include/boost/graph/detail/adjacency_list.hpp:263: warning: 'p$m_value' is used uninitialized in this function Line 263 in adjacency_list.hpp looks as follows: inline stored_edge_property(Vertex target, const Property& p = Property()) : stored_edge<Vertex>(target), m_property(new Property(p)) { } What am I doing wrong and how can I fix that? Thank you. Regards, Paul

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[filesystem] remove for directories
by Ovanes Markarian 07 Jun '07

07 Jun '07

Hello all! Is there any way to remove a directory using boost::filesystem? remove and remove_all throw an exception. Remove docs reference a POSIX remove(). There is written: [quote] If path does not name a directory, remove(path) shall be equivalent to unlink(path). If path names a directory, remove(path) shall be equivalent to rmdir(path). [/quote] Unfortunately remove does not behave so (on WinXP and Visual C++ 8). One more issue: the link to the POSIX remove() doc points to link() and not remove. With Kind Regards, Ovanes

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Signal not disconnecting?
by Christian Mol 07 Jun '07

07 Jun '07

Hi, I'm using the signal library in my application. However if I call disconnect() on my connection object the connection is not removed. Is this default behaviour? I would like not having this behaviour because the signal is connected to a member function within an object that is actually deleted. Any ideas? Regards, Christian

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BGL compile error
by gast128 07 Jun '07

07 Jun '07

Dear all, We want to (DLL) export a boost graph. Probably on (DLL) exporting, the compiler tries to generate code for every member function. However on VC++7.1 it gives then a problem with operator[]. This can be easily verified with the following case: void Foo() { boost::adjacency_list<> graph; graph[0]; } We use here Boost 1.33.0. Anyone an idea? Wkr, me

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[preprocessor] usage problem
by Christopher Lux 07 Jun '07

07 Jun '07

hi, i want to do the following in a win32 project, which generates a dlls. commonly there is a macro defined like this: #ifdef DLL_BUILD #define __scm_export __declspec(dllexport) #else #define __scm_export __declspec(dllimport) #endif now i have several projects which generate dlls and depend on each other like: core_lib <- graphics_lib now to do this it is needed to differenciate between dll builds. lets say with a macro CORE_DLL_BUILD and GFX_DLL_BUILD. BUT i think this is hell ;) and thought of something like this: i would like to have one macro __scm_export(lib) which decides by the lib parameter which lib is build. i tried it the following way: (code broken out of context) #include <boost/preprocessor.hpp> #include <boost/preprocessor/detail/is_nullary.hpp> #if SCM_COMPILER == SCM_COMPILER_MSVC #define __scm_export(lib) export_(BOOST_PP_EXPAND(BOOST_PP_CAT(SCM_BUILD_LIBRARY_, lib))) #define export_(lib) BOOST_PP_IF(BOOST_PP_IS_NULLARY(lib), __declspec(dllexport), __declspec(dllimport)) #define __scm_private(lib) #else #pragma error "unsupported compiler" #endif this way i only have to define something like /DSCM_BUILD_LIBRARY_core=() for the core project and /DSCM_BUILD_LIBRARY_ogl=() for the graphics library and use __scm_export(ogl) and __scm_export(core) in the particular libraries. this works perfectly, BUT i am searching for a more elegant way to do this, because i do not like the definition of a unary macro for the projects. i would like more to define it this way: /DSCM_BUILD_LIBRARY=core and /DSCM_BUILD_LIBRARY=ogl for the libs. i experimented with BOOST_PP_IIF and so on, but the problem is if these macros are presented with an undefined macro (like when i use the one lib in the other) they do not use the false alternative and insert a lengthy macro. after a long night i came up with the BOOST_PP_IS_NULLARY workaround, but as is said i do not think is is a very good solution. dies anyone have suggestions how to solve this on a more elegant way? Thanks -chris -- Christopher Lux | | Bauhaus University Weimar | Faculty of Media - Virtual Reality Systems Group

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[date_time] Posix timespec support?
by Terry G 07 Jun '07

07 Jun '07

Does date_time support POSIX timespec? I assume that timespec is standard POSIX. Is it not? If so, is it supported now, or how should it be supported. I'd be willing to help. terry

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Operator overloading and enable_if
by Bill Buklis 07 Jun '07

07 Jun '07

For a template class I'd like to add * and -> operators for types that support it (mainly pointers). However, most instantiations of this class won't be pointers and therefore these operators won't be valid. I understand that enable_if can't directly support member functions. But, how can I do the equivalent of this? template< typename T > class Sample { T data; public: Sample( T& data ) : data(data) { } typename boost::enable_if< boost::is_pointer<T>, T >::type operator->() const { return(data); } typename boost::enable_if< boost::is_pointer<T>, typename boost::remove_pointer<T>::type >::type operator*() const { return(*data); } };

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[mpl] Fusion/MPL examples
by Zeljko Vrba 06 Jun '07

06 Jun '07

The fusion library manual gives a single example and says "this is just the tip of the iceberg". I was wondering whether the slides/materials from the Boost Conference are available? I'm most interested in the lectures "Boost Metaprogramming Concepts and Frameworks" and "Fusion by example". I'm in the process of (slowly) reading THE "MPL book" (by Dave and Alexei), but I'm looking for more "down-to-earth" examples, rather than constructing small DSLs or creating optimized versions of swap. Synopses of the above lectures contain: "We'll also get a taste of high-level metaprogramming abstractions by using several Boost metaprogramming librariesMPL, Preprocessor, and the Fusion tuple library to solve real problems." "The emphasis for the examples will be on using Boost.Fusion in application code, rather than as infrastructure for library developers." I'm in the process of writing a recursive data structure with very similar operations at every level, but still with small behavioral variations. It seems like a perfect problem for metaprogramming, but I fail to map MPL's type manipulation routines to my down-to-earth problem. I was hoping to get some more insight in MPL from the materials for the abovementioned lectures. Get a new perspective and background to keep in mind while reading the MPL book. So, I kindly ask Dave Abrahams, Dan Marsden and Joel de Guzman to make their lecture materials available on-line, if possible. Thanks and best regards, Zeljko.

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Re: [Boost-users] [serialization] Wrapper + make_nvp woes
by Dan Thill 06 Jun '07

06 Jun '07

Thank you for the fast reply, Robert. > Another idea is to cast your character array to a ... > character array - like static_cast< int [64] &>(my array address) > but that would require a constant size which might not work > for you. I'm not certain I quite understand this. Perhaps I didn't get my thoughts down coherently. I'm seeking to write my serialization like this (sorry I forgot to include this in my initial msg): char some_array[5] = "test"; .... ar & make_nvp("some_array", make_char_array(some_array, 5)); And obtain the following output: output.xml: ... <some_array>test</some_array> output.txt: .... 4 test .... --------------------------- My aforementioned make_char_array() works fine for text archives--just not when the result is composed with make_nvp(). > Finally you can use the blunt instrument approach. > > save(.... > std::string temp_string; > // copy data into temp_string > ar << temp_string > > load > .. do the opposite. Which is pretty much what my serialization wrapper is doing (this is in fact, what I wrote initially, before trying to make it a serialization wrapper). While I can certainly do the blunt approach, it will require me to split my serialization function :(

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