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BGL in mangaged C++ (.Net )
by Bill Eidson 05 Aug '04

05 Aug '04

Has anyone had success running the BGL from with managed C++ code? I have code that compiles fine, but at runtime throws a .Net exception called TypeLoadException. Googleing and documentation I have read are no help. The graph used is a plain vanilla adjacency_list<> and the exception occurs durring the resize operation of the vertex vector. thanks in advance bille

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RE: [Boost-users] "using namespace" in template implementation fi les
by Jim.Hyslop 05 Aug '04

05 Aug '04

Erik Thiele wrote: > usually in normal non-template coding style i can do > > using namespace std; > > on the top of each .cpp file. but now i cannot do it, because it is > actually in a header file and i don't want to include another > namespace > in the interface definition. > > how can i solve the problem? i don't want to write "using > namespace std" > at the beginning of every template function declaration, but only once > per implementation file. Unfortunately, you can't. Unless you can find a way to move the function definitions out of line, into a separate file - then it would be treated as any other .cpp file. -- Jim Hyslop Senior Software Designer Leitch Technology International Inc. (http://www.leitch.com) Columnist, C/C++ Users Journal (http://www.cuj.com/experts)

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Re: [Boost-users] "using namespace" in template implementation files
by Jeff Williams 05 Aug '04

05 Aug '04

I think typically the solution is to just prefix std:: to everything. Once you get used to doing it, it doesn't even seem cumbersome anymore. (well that's my opinion at least) > > From: Erik Thiele <erik(a)thiele-hydraulik.de> > Date: 2004/08/05 Thu AM 09:27:10 EDT > To: boost-users(a)lists.boost.org > Subject: [Boost-users] "using namespace" in template implementation files > > hi > > i don't find any docs about that issue, so i ask it here: > > the usual approach to work with templates and separated > interface and implementation is as follows (i hope): > > x.hpp: > > template<class a> void foo(std::string xxx); > #include "x_impl.hpp" > > > x_impl.hpp: > > template<class a> void foo(std::string xxx) > { > string bla = xxx + "sdjkfh"; // <-- no std:: here !!!! > cout << bla; > } > > > > usually in normal non-template coding style i can do > > using namespace std; > > on the top of each .cpp file. but now i cannot do it, because it is > actually in a header file and i don't want to include another namespace > in the interface definition. > > how can i solve the problem? i don't want to write "using namespace std" > at the beginning of every template function declaration, but only once > per implementation file. > > > cu & thx > erik > > > -- > Erik Thiele > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

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"using namespace" in template implementation files
by Erik Thiele 05 Aug '04

05 Aug '04

hi i don't find any docs about that issue, so i ask it here: the usual approach to work with templates and separated interface and implementation is as follows (i hope): x.hpp: template<class a> void foo(std::string xxx); #include "x_impl.hpp" x_impl.hpp: template<class a> void foo(std::string xxx) { string bla = xxx + "sdjkfh"; // <-- no std:: here !!!! cout << bla; } usually in normal non-template coding style i can do using namespace std; on the top of each .cpp file. but now i cannot do it, because it is actually in a header file and i don't want to include another namespace in the interface definition. how can i solve the problem? i don't want to write "using namespace std" at the beginning of every template function declaration, but only once per implementation file. cu & thx erik -- Erik Thiele

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binding a member variable?
by Russell Hind 05 Aug '04

05 Aug '04

Is it possible to have a member variable in a bind expression or do I need to have an accessor method for the variable? E.g. I have the following structure and I want to use min_elemnt to find the point with the lowest m_Z value in a vector. class Point_c { public: double m_X; double m_Y; double m_Z; } Thanks Russell

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question about an implementation detail in boost::shared_ptr
by Jeff Williams 04 Aug '04

04 Aug '04

I was reading through the boost::shared_ptr source code, and I have a question about one small detail. This is in boost release 1.31.0: Around line 84 we have this code: // enable_shared_from_this support template<class T, class Y> void sp_enable_shared_from_this(boost::enable_shared_from_this<T> * pe, Y * px, shared_count const & pn) { if(pe != 0) pe->_internal_weak_this._internal_assign(px, pn); } I was curious, why is this function not inline? Jeff

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RE: [Boost-users] Re: Looking for some help with boost::thread::sleep()
by Kutch, Patrick G 04 Aug '04

04 Aug '04

Not a problem. It looks as if it goes into the # elif defined(BOOST_HAS_NANOSLEEP) section. Patrick Kutch Life is too short to drink bad coffee. -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Michael Glassford Sent: Tuesday, August 03, 2004 4:20 PM To: boost-users(a)lists.boost.org Subject: [Boost-users] Re: Looking for some help with boost::thread::sleep() Kutch, Patrick G wrote: > Has nobody else experienced this? Sorry, I forgot all about answering your original post. If you look at the thread::sleep() method, it looks like the following; can you tell me which path it's taking (there are several options for pthreads) when you have the problem? void thread::sleep(const xtime& xt) { for (int foo=0; foo < 5; ++foo) { #if defined(BOOST_HAS_WINTHREADS) int milliseconds; to_duration(xt, milliseconds); Sleep(milliseconds); #elif defined(BOOST_HAS_PTHREADS) # if defined(BOOST_HAS_PTHREAD_DELAY_NP) timespec ts; to_timespec_duration(xt, ts); int res = 0; res = pthread_delay_np(&ts); assert(res == 0); # elif defined(BOOST_HAS_NANOSLEEP) timespec ts; to_timespec_duration(xt, ts); // nanosleep takes a timespec that is an offset, not // an absolute time. nanosleep(&ts, 0); # else mutex mx; mutex::scoped_lock lock(mx); condition cond; cond.timed_wait(lock, xt); # endif #elif defined(BOOST_HAS_MPTASKS) int microseconds; to_microduration(xt, microseconds); Duration lMicroseconds(kDurationMicrosecond * microseconds); AbsoluteTime sWakeTime(DurationToAbsolute(lMicroseconds)); threads::mac::detail::safe_delay_until(&sWakeTime); #endif xtime cur; xtime_get(&cur, TIME_UTC); if (xtime_cmp(xt, cur) <= 0) return; } } Mike _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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RE: [Boost-users] Looking for some help with boost::thread::sleep()
by Kutch, Patrick G 03 Aug '04

03 Aug '04

Has nobody else experienced this? Patrick Kutch Life is too short to drink bad coffee. -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Kutch, Patrick G Sent: Thursday, July 22, 2004 8:07 PM To: boost-users(a)lists.boost.org Subject: [Boost-users] Looking for some help with boost::thread::sleep() I am used to putting in quick sleep() statements in my worker threads, usually a sleep(0) just to give up a timeslice, or maybe a sleep(1). Of course boost::thread::sleep takes an xtime object not a milliseconds value, so I wrote a small routine to simulate the sleep() statement using boost::thread::sleep: void inline UtilitySleep(long milliSeconds) { const int NANOSECONDS_PER_MILLISECOND = 1000000; if (0 == milliSeconds) { boost::thread::yield(); // just do a yield return; } boost::xtime time; int sec = 0; // if larger than 1 sec, do some voodoo for the boost::xtime struct if (milliSeconds >= 1000) { // convert ms > 1000 into secs + remaining ms int secs = milliSeconds /1000; milliSeconds = milliSeconds - secs*1000; sec += secs; } milliSeconds*=NANOSECONDS_PER_MILLISECOND; // normal boost time sleep stuff // get current time boost::xtime_get(&time,boost::TIME_UTC); // add # of desired secs and ms time.nsec+=milliSeconds; time.sec+= sec; // sleep until that time boost::thread::sleep(time); } It seems to always work fine unde Windows, however occasionally under Linux it appears that if I use a small value, such as sleep(2) that sometimes it takes longer to setup the values and call boost::thread:sleep() and I end up passing an xtime value that has already passed, basically blocking the thread forever. Anybody have any advice for me? Thanx! - Patrick _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Looking for a simple example of instantiating normal_distribution from the random library correctly
by Kuntz, David A 03 Aug '04

03 Aug '04

> I am instantiating normal_distribution from the random > library incorrectly and looking for a simple example of how to do it > correctly. > > I compiled, built and ran random_test.cpp and can see > when I step through the normal_distribution () operator that _r1 and > _r2 have values < 1. > > Here are the relevant excerpts from my incorrect attempt > at instantiation and calling the () operator: > > typedef boost::mt19937 base_generator_type; > > boost::uint32_t x = 42u; > Ideal4045EsmModel::base_generator_type > base_generator(x); > > double randomDrawResult; > > boost::normal_distribution<double> boostNormalRand; > > boostNormalRand.reset(); > > randomDrawResult = boostNormalRand(base_generator); > > This compiles, builds, and runs, but when I step through > the normal_distribution () operator, _r1 and _r2 have very large > positive values, resulting in an attempt to take the log of a > negative number and an Indefinite value being returned. > > I am a relatively inexperienced C++ developer. I have > built and stepped through random_test.cpp > (http://www.boost.org/libs/random/random_test.cpp) and can see that > its gets correct results, but I found it quite difficult to follow. Is > there anyone out there who could show me a simpler way? > > Thanks, > > Dave > > > >

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Bidirectionnal filtered multigraph
by Robert weldon 03 Aug '04

03 Aug '04

I've created a bidirectional filtered multigraph from an adjacency_list with vectorS and listS as containers for the vertices and egdes respectively. It seems the function edge(u,v,g) does not work properly for this kind of graph. I can detect the existence of an edge (u,v) if I iterate explicitly through the out_edges of the filtered graph but not if I use edge() directly on the filtered graph. Also, I get an exception when I remove an edge that was invisible to the edge(u,v,g) function while the bidirectionnal version of remove_edge for adjacency_list is erasing the edge ID form the in_edge list of the graph. Any idea why edge() does not work in this case? Patrick --------------------------------- Do you Yahoo!? New and Improved Yahoo! Mail - Send 10MB messages!

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