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RE: [Boost-Users] Boost.Threads question
by James Zappia 05 Dec '02

05 Dec '02

> Thanks for all you help. I have a few new questions now, though. ;) > Again, I'm a newbie to C++ so this may seem stupid... > > I created a boost::thread object and even though it goes out of scope, > the thread continues to run. > >As it should, and as it's well documented. The boost::thread object is >analogous to a std::fstream, where the file doesn't get deleted when the >object goes out of scope. In other words, it's just a handle to the >actual running thread. Understood. > Also, when passing a class with the > operator() defined to boost::thread, it constructs and destructs the > object several times which seems odd. > >Also well documented, and essential. If this didn't occur, you'd have to >insure the lifetime of the object passed was longer than the lifetime of >the thread of execution (not the boost::thread object, the actual thread >of execution). Understood. > What I'm basically trying to do > is run a thread, have that thread lock a timed_mutex, then do its job. > Then, in main, I try to lock the same timed_mutex and if I can't get a > lock before the time expires, I need to terminate the thread. Below is > the source code and the output generated. My questions are below, after > the output. > > SOURCE: > #include <iostream> > #include <boost/thread/xtime.hpp> > #include <boost/thread/thread.hpp> > #include <boost/thread/exceptions.hpp> > > using namespace std; > > boost::timed_mutex mutex; > > class thread_class > { > public: > explicit thread_class(int sleep): _sleep(sleep) {}; > > void operator()() > { > boost::xtime xt; > > cout << "thread: locking mutex\n"; > boost::timed_mutex::scoped_timed_lock lock(mutex,true); > >Why do you continue to use this syntax? This performs an explicit lock, >not a timed lock. This overload is for two use cases: > >1) Creating an unlocked lock object: > >scoped_time_lock lock(mutex, false); > >2) Creating a locked lock object which later will be unlocked and then >locked again through a timed lock: > >scoped_time_lock lock(mutex, true); >// .. some code >lock.unlock(); >// .. some code >if (lock.timed_lock()) { > // .. some code >} > >Obviously the second use case will be extremely rare. In your case you're >doing neither of these, and you'd be better served just using a simple >scoped_lock. > > boost::xtime_get(&xt,boost::TIME_UTC); > > cout << "thread: sleeping for " << _sleep << " seconds\n"; > > xt.sec += _sleep; > boost::thread::sleep(xt); > > cout << "thread: freeing lock -- goodbye\n"; > } > > ~thread_class() { cout << "thread_class destructed\n"; } > > private: > int _sleep; > }; > > int main( void ) > { > { > cout << "main: creating thread\n"; > > thread_class test(10); > boost::thread thrd(test); > > cout << "main: sleeping for 2 seconds\n"; > sleep(2); > > cout << "main: trying to lock mutex -- waiting 5 > seconds...\n"; > > boost::timed_mutex::scoped_timed_lock lock(mutex,false); > > boost::xtime xt; > boost::xtime_get(&xt,boost::TIME_UTC); > xt.sec += 5; > > if ( lock.timed_lock(xt) ) > { > cout << "obtain lock -- joining thread\n"; > thrd.join(); > } > else > { > cout << "failed to obtain lock\n"; > } > } > >I'd code this as: > >boost::xtime xt; >boost::xtime_get(&xt, boost::TIME_UTC); >xt.sec += 5; >boost::timed_mutex::scoped_time_lock lock(mutex); >if (lock) // or if (lock.locked()) >{ >// etc I assume you mean boost::timed_mutex::scoped_timed_lock lock(mutex,xt) because I don't see a constructor that takes only a timed_mutex. That said, I agree that your way of doing it is better. Above you asked why I continue to use the syntax I do for locking the mutex in the thread. I want to immediately lock it, then in the main thread try to lock it for a finite amount of time. I can't do that with scoped_lock. Perhaps my strategy is wrong. I want to run a thread for only a specified amount of time. I can't afford to block on a join() to wait for that thread to finish. > cout << "main: making sure thread is gone\n"; > >That's what join is for. I realize this is a toy example, but I can't see >a valid reason for coding it this way. All you've done is introduce race >conditions, even if they are conditions you can feel fairly confident will >do what you want. > > sleep(10); > > return 0; > } > > OUTPUT: > main: creating thread > thread_class destructed > thread_class destructed > thread_class destructed > thread_class destructed > main: sleeping for 2 seconds > thread: locking mutex > thread: sleeping for 10 seconds > main: trying to lock mutex -- waiting 5 seconds... > failed to obtain lock > thread_class destructed > main: making sure thread is gone > thread: freeing lock -- goodbye > thread_class destructed > > 1) Why are so many thread_class objects constructed/destructed when > calling boost::thread? > >The number surprises me a little. I'd have expected two copies, knowing >what I do about the implementation and with out carefully evaluating the >code here. But the documentation is clear that the object will be copied >AT LEAST once, and is free to copy the object any number of times. You >need to account for this in your implementation if it matters. Understood. Apologies for not thoroughly reading the doc first. > 2) After the thread object (test) goes out of scope, why does the thread > continue to run? Is it copied when calling boost::thread and run > detached from the main thread? > >I don't know what you mean by "run detached from the main thread", but >yes, test IS copied (but then, you know that based on what you asked in >1). But then, maybe you meant something else. The "thread object" is >actually "thrd" in your code above, not "test". > > 3) Is there a way I can cancel a thread if going out of scope doesn't > stop it? > >Not yet, but there will be. However, I'm not sure that what you want to >do is really to cancel the thread. It's hard to tell from this toy >example. What the application does is run a job (thread) that has a finite amount of time to finish. If it doesn't finish in that time it needs to send an alert and explicitly terminate the thread (because it can't be blocked with a join() unless it knows the thread is done). As stated above, perhaps my strategy of using the mutex to see if a thread ran in a given amount of time is wrong. Hopefully I'm making some sense, if not, I apologies. James >William E. Kempf Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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ublas::matrix debugging values
by Nick Toze 05 Dec '02

05 Dec '02

Hello, I'm using ublas in MSVC6. How do I find out the values of elements of a matrix when debugging? If I try putting for example mat[0][0] in the 'watch' window then it says 'CXX0058: Error: overloaded operator not found'. Thanks in advance, Nick

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[Fwd: [Boost-Users] Deadlocking problems with recursive_mutex on Linux with boost 1.29.0]
by William E. Kempf 05 Dec '02

05 Dec '02

I'm not sure if _XOPEN_SOURCE or _GNU_SOURCE are defined by the configuration headers or not. It does sound to me, however, like things may well be working on Linux properly and we might just have a user error. Again, can I get a test case for this in order to verify precisely what's wrong? Bill Kempf -------- Original Message -------- Subject: [Boost-Users] Deadlocking problems with recursive_mutex on Linux with boost 1.29.0 From: Dan Nuffer <dnuffer(a)sco.com> Date: Thu, December 5, 2002 10:02 am To: wekempf(a)cox.net Hmm, seems yahoogroups won't let me send an e-mail to boost-users, I guess I subscribed with a different e-mail addr, so I'll just send this directly to you. Subject: Re: [Boost-Users] Deadlocking problems with recursive_mutex on Linux with boost 1.2 9.0 From: Dan Nuffer <dnuffer(a)sco.com> Date: Wed, 04 Dec 2002 17:13:15 -0700 To: Boost-Users(a)yahoogroups.com William E. Kempf wrote: >> Hi >> >> I experienced a lot of deadlocking situations when I used >> recursive_mutex on SuSE Linux 8.1. When I analysed this mutex code I found out, that the implementation of recursive_mutex on Linux is based on recursive POSIX mutexes (set with pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)). Things were getting interesting when I didn't find a man page for this function and I started to suspect Linux not having implemented this mutex type. >> >> The next thing I had done was to disable recursive POSIX mutexes by commenting out the line "#define BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE" in the file boost_1_29_0/boost/config/posix_features.hpp" forcing boost to implement recursive_mutex by itself. > > > > Interestingly enough, the manpages indicate that Linux has a > pthread_mutexattr_setkind_np that does the same thing as > pthread_mutexattr_settype. I'm not a POSIX programmer, so I'm feeling my way around blindly with some of these more esoteric optional and/or new features. I'm not sure how to correctly detect the availability here, and > to configure accordingly. I'll have to research this particular case for a fix. If anyone knows how to fix the configuration here, please speak up. > Linux definitely has the required functions/functionality. See http://sources.redhat.com/cgi-bin/cvsweb.cgi/libc/linuxthreads/mutex.c?rev=… However, in the pthread.h header, the stuff is inside of: #ifdef __USE_UNIX98 To activate it, you should #define _XOPEN_SOURCE 500 or #define _GNU_SOURCE before you actually include anything (best to use -D cmd line arg). > One thing that confuses me... how does this even compile on Linux? If the > pthread_mutexattr_settype function is available to the compiler/linker, why on earth would it not function properly? Definately need to do some research. > > Also, if you have a simple test case that reproduces the deadlock it would > be beneficial for you to send it to me for addition to the test harness. > > >> Since then everything is working quite perfectly! >> >> But I'd like to raise some questions: >> * Is my assumption correct that Linux doesn't have a proper support for recursive POSIX mutexes? > > > > It has support, evidently, possibly just not "proper" support. (Or maybe it does have proper support that's just not documented and we have an implementation problem on my end?) > Linux's implementation looks okay to me. However, it not documented in the man pages. If you have any other questions or anything I can help you out with wrt Linux, just let me know. --Dan William E. Kempf Booster (http://www.boost.org) Boost.Threads author

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Deadlocking problems with recursive_mutex on Linux with boost 1.2 9.0
by beat.schaer＠ruag.com 05 Dec '02

05 Dec '02

Hi I experienced a lot of deadlocking situations when I used recursive_mutex on SuSE Linux 8.1. When I analysed this mutex code I found out, that the implementation of recursive_mutex on Linux is based on recursive POSIX mutexes (set with pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)). Things were getting interesting when I didn't find a man page for this function and I started to suspect Linux not having implemented this mutex type. The next thing I had done was to disable recursive POSIX mutexes by commenting out the line "#define BOOST_HAS_PTHREAD_MUTEXATTR_SETTYPE" in the file boost_1_29_0/boost/config/posix_features.hpp" forcing boost to implement recursive_mutex by itself. Since then everything is working quite perfectly! But I'd like to raise some questions: * Is my assumption correct that Linux doesn't have a proper support for recursive POSIX mutexes? * Can I expect that this problem will be solved in a future release of boost? Regards Beat

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RE: [Boost-Users] Boost.Threads question
by James Zappia 05 Dec '02

05 Dec '02

> Thank you, that worked. I see what I was doing wrong. > > One thing I don't understand about the alternative method... > >> boost::try_mutex::scoped_try_lock lock(mutex); // does a try_lock >> while (!lock) { >> cout << "trying..."; >> lock.try_lock(); >> } > > How does "!lock" in the "while (!lock) { ... }" statement determine > whether it's true or false? Does it call a function in the > scoped_try_lock class? (sorry if that's a lame question...) >Hmmm... this doesn't seem to be documented very well. I'll have to fix >that. What it does is invoke operator void*() for a boolean test (this >mechanism also should be updated to use the safe_bool idiom as well). >Alternatively, you could call lock.locked() (which also appears to be >poorly documented). Thanks for pointing out these deficiencies. >William E. Kempf Thanks for all you help. I have a few new questions now, though. ;) Again, I'm a newbie to C++ so this may seem stupid... I created a boost::thread object and even though it goes out of scope, the thread continues to run. Also, when passing a class with the operator() defined to boost::thread, it constructs and destructs the object several times which seems odd. What I'm basically trying to do is run a thread, have that thread lock a timed_mutex, then do its job. Then, in main, I try to lock the same timed_mutex and if I can't get a lock before the time expires, I need to terminate the thread. Below is the source code and the output generated. My questions are below, after the output. SOURCE: #include <iostream> #include <boost/thread/xtime.hpp> #include <boost/thread/thread.hpp> #include <boost/thread/exceptions.hpp> using namespace std; boost::timed_mutex mutex; class thread_class { public: explicit thread_class(int sleep): _sleep(sleep) {}; void operator()() { boost::xtime xt; cout << "thread: locking mutex\n"; boost::timed_mutex::scoped_timed_lock lock(mutex,true); boost::xtime_get(&xt,boost::TIME_UTC); cout << "thread: sleeping for " << _sleep << " seconds\n"; xt.sec += _sleep; boost::thread::sleep(xt); cout << "thread: freeing lock -- goodbye\n"; } ~thread_class() { cout << "thread_class destructed\n"; } private: int _sleep; }; int main( void ) { { cout << "main: creating thread\n"; thread_class test(10); boost::thread thrd(test); cout << "main: sleeping for 2 seconds\n"; sleep(2); cout << "main: trying to lock mutex -- waiting 5 seconds...\n"; boost::timed_mutex::scoped_timed_lock lock(mutex,false); boost::xtime xt; boost::xtime_get(&xt,boost::TIME_UTC); xt.sec += 5; if ( lock.timed_lock(xt) ) { cout << "obtain lock -- joining thread\n"; thrd.join(); } else { cout << "failed to obtain lock\n"; } } cout << "main: making sure thread is gone\n"; sleep(10); return 0; } OUTPUT: main: creating thread thread_class destructed thread_class destructed thread_class destructed thread_class destructed main: sleeping for 2 seconds thread: locking mutex thread: sleeping for 10 seconds main: trying to lock mutex -- waiting 5 seconds... failed to obtain lock thread_class destructed main: making sure thread is gone thread: freeing lock -- goodbye thread_class destructed 1) Why are so many thread_class objects constructed/destructed when calling boost::thread? 2) After the thread object (test) goes out of scope, why does the thread continue to run? Is it copied when calling boost::thread and run detached from the main thread? 3) Is there a way I can cancel a thread if going out of scope doesn't stop it? Thanks again, James Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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boost::function and template member functions
by Markus Werle 05 Dec '02

05 Dec '02

Hi! With the help of ConcreteEvoker I was able to get an (indirect) address for Test::Apply<double>. This address is obtained via automatic template instantiation, so I feel like there must be a way to achiev the same thing without ConcreteEvoker. Any comments? #include <iostream> #include "boost/function.hpp" #include "boost/bind.hpp" struct Test { template <class T> static T Apply(T t1, T t2) { return t1 + t2; } }; template <class T, class OP> struct ConcreteEvoker { static T Apply(T d1, T d2) { return OP::Apply(d1, d2); } }; int main() { boost::function<double (double, double)> test = &ConcreteEvoker<double, Test>::Apply; std::cerr << test(1.0, 2.0) << std::endl; }

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to add a function to the BGL
by Ramón Casero Cañas 05 Dec '02

05 Dec '02

Let's say I've written a function to prune edges of a graph (data structures and methods are those of the BGL), in the typical C-way (declare the function header in a .h file, and write the code in the .c file). Ok, it works, but I'm not fully satisfied. I would like to make it more BGL-like. So I use templates for generic graphs, include concept check lines in my code, and I have to forget about the .h and .c style, as templates behave a little like macros, and you cannot split the declaration and definition in two files. But, is there a better way to do this, like when you add you own internal property to the graph with BOOST_INSTALL_PROPERTY? Regards, Ramón.

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object_pool use ordered_malloc ordered_free. why?
by wugui 05 Dec '02

05 Dec '02

boost_1_28_0 if construct only, and freeall in ~object_pool. i think it is good. can i use object_pool to replace 'new delete'? the destroy is slow. thank for any advice. newbie and not good at english. full test code: #include <boost/pool/object_pool.hpp> #include <vector> #include <iostream> #include <time.h> #include <stdlib.h> struct Some { std::string ss; int ii; char cc[32]; }; int main(int argc, char * argv[]) { boost::object_pool<Some> pool; std::vector<Some*> v_Some; int count = 20000; time_t t = time(0); std::cout << ctime(&t) << std::endl; for (int i=0; i<count; ++i) { Some * s = pool.construct(); if (s) v_Some.push_back(s); else break; } t = time(0); std::cout << v_Some.size() << ctime(&t) << std::endl; if (argc > 1) { // fast for (std::vector<Some*>::reverse_iterator it = v_Some.rbegin(); it != v_Some.rend(); ++it) pool.destroy(*it); } else { // slow for (std::vector<Some*>::iterator it = v_Some.begin(); it != v_Some.end(); ++it) pool.destroy(*it); } t = time(0); std::cout << ctime(&t) << std::endl; return 0; }

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RE: [Boost-Users] Boost.Threads question
by James Zappia 04 Dec '02

04 Dec '02

Thank you, that worked. I see what I was doing wrong. One thing I don't understand about the alternative method... > boost::try_mutex::scoped_try_lock lock(mutex); // does a try_lock > while (!lock) { > cout << "trying..."; > lock.try_lock(); > } How does "!lock" in the "while (!lock) { ... }" statement determine whether it's true or false? Does it call a function in the scoped_try_lock class? (sorry if that's a lame question...) Thanks again for the help, very much appreciated. James Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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RE: [Boost-Users] Boost.Threads question
by James Zappia 04 Dec '02

04 Dec '02

> I'm a newbie to C++ and Boost and I'm trying to port a threaded C > program I have to Boost.Threads. I'm trying to use scoped_try_lock to > test a lock on mutex and it's not working. I'm obviously doing > something wrong but I can't figure it out. Below is the source code. > Any help would be greatly appreciated. >>How is it not working? What do you expect to happen? What I want to happen is that the main thread keeps trying the lock until it's freed. > SOURCE: > > #include <iostream> > #include <boost/thread/thread.hpp> > #include <boost/thread/exceptions.hpp> > > using namespace std; > > boost::try_mutex mutex; > > void thread_test( void ) > { > cout << "thread: locking mutex\n"; > > { > boost::try_mutex::scoped_try_lock lock(mutex); > cout << "thread: sleeping for 10 seconds\n"; > sleep(10); > } > > cout << "thread: unlocked mutex - goodbye!\n"; > > return; > } > > int main( void ) > { > cout << "main: creating thread\n"; > boost::thread thread(thread_test); > > cout << "main: sleeping for 2 seconds\n"; > sleep(2); > > cout << "main: trying to lock mutex\n"; > boost::try_mutex::scoped_try_lock lock(mutex,true); >>This will force a lock (which means we'll block until the thread releases >>the lock). > while ( !lock.try_lock() ) >>Since the above insured the mutex is already locked, this would be a >>recursive lock which should result in a thread_lock_error exception being >>thrown. Is this not what's happening for you? That is what's happening. As stated above, what I would like to happen is the main thread continuously try the lock until it's freed. What am I doing wrong? Thanks for the help! James > cout << "main: retrying to lock mutex\n"; > > cout << "main: joining thread\n"; > thread.join(); > > cout << "main: thread joined\n"; > return 0; > } >>William E. Kempf Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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Boost.Threads question
by James Zappia 04 Dec '02

04 Dec '02

Hi, I'm a newbie to C++ and Boost and I'm trying to port a threaded C program I have to Boost.Threads. I'm trying to use scoped_try_lock to test a lock on mutex and it's not working. I'm obviously doing something wrong but I can't figure it out. Below is the source code. Any help would be greatly appreciated. Thanks, James SOURCE: #include <iostream> #include <boost/thread/thread.hpp> #include <boost/thread/exceptions.hpp> using namespace std; boost::try_mutex mutex; void thread_test( void ) { cout << "thread: locking mutex\n"; { boost::try_mutex::scoped_try_lock lock(mutex); cout << "thread: sleeping for 10 seconds\n"; sleep(10); } cout << "thread: unlocked mutex - goodbye!\n"; return; } int main( void ) { cout << "main: creating thread\n"; boost::thread thread(thread_test); cout << "main: sleeping for 2 seconds\n"; sleep(2); cout << "main: trying to lock mutex\n"; boost::try_mutex::scoped_try_lock lock(mutex,true); while ( !lock.try_lock() ) cout << "main: retrying to lock mutex\n"; cout << "main: joining thread\n"; thread.join(); cout << "main: thread joined\n"; return 0; }

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compose, bind and a doubled ref problem
by Markus Werle 04 Dec '02

04 Dec '02

Hi! The code below compiles fine if You return to Value semantics and replace "const Vector&" with "Vector". But with reference to vector two compilers (Intel-7.0 and gcc-3.2.1) "throw" with a "reference to reference" error. How can I achieve what I want here? Do I have to apply cref somewhere? I do not want to change the type of "l" in this example. Also the signature of Vector::operator() and GetValue is fixed. Anything else may undergo a change. #include <iostream> #include <cstddef> #include "boost/function.hpp" #include "boost/bind.hpp" #include "boost/compose.hpp" struct Vector { double operator()(size_t j) const { std::cerr << "get value at index " << j << std::endl; return 99.0; } }; double GetValue(const Vector& V, size_t j) { return V(j); } double Add(double d1, double d2) { return d1 + d2; } int main() { using namespace boost; Vector V; function<double (const Vector&, size_t)> g = GetValue; function<double (const Vector&)> h1 = bind(g, _1, 5); function<double (const Vector&)> h2 = bind(g, _1, 4); function<double (double, double)> Adder = Add; function<double (const Vector&)> l = compose_f_gx_hx(Adder, h1, h2); std::cerr << l(V) << std::endl; }

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error linking debug version boost_regex with Solaris compiler
by kurt_zhang 03 Dec '02

03 Dec '02

I compiled boost_regex lib on Solaris using the following compiler: > CC -V CC: Sun WorkShop 6 update 2 C++ 5.3 2001/05/15 The version without using -g links fine, however, when I compiled the lib with -g option using provided makefile sunpro_dbx.mk, the lib was built OK; then I tried to compile provided test programs using libs/regex/test/regress/sunpro_dbx.mk, I got the following error: > make -f sunpro_dbx.mak mkdir -p r mkdir -p rm rm -f *.o rm -fr SunWS_cache CC -I../../../../ -I./ -L../../build/sunpro_dbx -g -o r/regress tests.cpp parse.cpp regress.cpp -lboost_regex tests.cpp: parse.cpp: regress.cpp: Undefined first referenced symbol in file boost::detail::allocator<unsigned char>::allocator<char>#Nvariant 1 (const boost::detail::allocator<__type_1>&) /fsys/home/zhangku/re/libs/regex/ test/regress/SunWS_cache/CC_obj_O/OhCenAP7d5aN-_Bfr3wh.o boost::detail::allocator<unsigned char>::allocator<wchar_t>#Nvariant 1 (const boost::detail::allocator<__type_1>&) ../../build/sunpro_dbx/libboost_r egex.so ld: fatal: Symbol referencing errors. No output written to r/regress make: *** [r/regress] Error 1 Can anyone help me on this? Kurt

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Lambda questions
by Claus Rasmussen 02 Dec '02

02 Dec '02

Is it possible to discern one-argument lambda expressions from two-argument expressions ? I would like to do something like this: template<typename UNARY_LAMBDA_FUNC> void f(UNARY_LAMBDA_FUNC ulf) { ulf(arg); } template<typename BINARY_LAMBDA_FUNC> void f(BINARY_LAMBDA_FUNC blf) { blf(arg1, arg2); } -Claus

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RE: [Boost-Users] Re: Extended use of BGL File Dependency Example
by Tom Matelich 02 Dec '02

02 Dec '02

From: David Abrahams [mailto:dave@boost-consulting.com] > Tom Matelich <tmatelich(a)zetec.com> writes: > > > From: David Abrahams [mailto:dave@boost-consulting.com] > > Sent: Sunday, December 01, 2002 5:58 AM > >> Tom Matelich <tmatelich(a)zetec.com> writes: > >> > >> > trying to make my graphviz representation look nicer and I > >> was wondering if > >> > there is an algorithm already for simplifying: > > > > -----B\ > > A--< \ > > --------C > > D----------/ > > > > to: > > > > A---B---C > > D------/ > > > > This eliminated the A-C edge. > > > > Thanks for considering my problem. > > Maybe you want a minimum spanning tree, where the weight of each edge > in the tree is determined by the distance between its vertices in some > topological sort? > > That seems to solve the cases shown above pretty nicely. I had looked at the minimum spanning tree docs a bit, I thought it looked pretty good. The docs say undirected graph though. I'm currently using a directed graph. I suppose I could create a separate graph. Oh, I see, create an undirected graph with weights as you said, and use the minimum spanning algorithm to choose the useful edges. I like it, hope it works. Thanks, Tom ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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RE: [Boost-Users] Re: Extended use of BGL File Dependency Example
by Tom Matelich 02 Dec '02

02 Dec '02

From: David Abrahams [mailto:dave@boost-consulting.com] Sent: Sunday, December 01, 2002 5:58 AM > Tom Matelich <tmatelich(a)zetec.com> writes: > > > trying to make my graphviz representation look nicer and I > was wondering if > > there is an algorithm already for simplifying: > > > > -----B\ > > A--< \ > > --------C > > > > to: > > > > A---B---C > > > > of course this is happening on a much larger scale. > > > > Thanks for any input you might have, > > That's known as a "topological sort", and can be done easily with a > depth-first search. I believe the graph library already has one: > > http://www.boost.org/libs/graph/doc/topological_sort.html > Hmm, its a little more complicated (I think). I'm using the topological sort for determining a build order. Now, I basically want to find a way to eliminate as many Edges as possible while still showing all dependencies. -----B\ A--< \ --------C D----------/ to: A---B---C D------/ This eliminated the A-C edge. Thanks for considering my problem. ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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RE: [Boost-Users] Warnings compiling smart_ptr_test.cpp under MSVC++ 6.0
by Randy Bowen 01 Dec '02

01 Dec '02

Visual Studio 6 maintained at 255-character limit on identifiers in its debug information. You'll see this warning with just about any usage of STL containers and non-simple data types. It's basically harmless... annoying, but harmless. Randy Bowen -----Original Message----- From: fejimush [mailto:greitz@tomotherapy.com] Sent: Wednesday, November 13, 2002 10:59 AM To: Boost-Users(a)yahoogroups.com Subject: [Boost-Users] Warnings compiling smart_ptr_test.cpp under MSVC++ 6.0 I am brand new to boost. I have been able to compile and link smart_ptr_test.cpp. I have also been able to successfully run the test without errors. Can anyone tell me why I am getting numerous warnings? (shown below) One more item, the warning takes me to c:\...\VC98\Include\UTILITY Is this a stl implentation problem? Thanks in advanced. ---------------Build Output----------------------- Compiling... smart_ptr_test.cpp c:\program files\microsoft visual studio\vc98\include\utility(25) : warning C4786: 'std::_Tree<boost::shared_ptr<int>,boost::shared_ptr<int>,std:: set<boost::shared_ptr<int>,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > > ::_Kfn,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::iterator' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\libs\smart_ptr\smart_ptr_test.cpp(198) : see reference to class template instantiation 'std::pair<std::_Tree<boost::shared_ptr<int>,boost::shar ed_ptr<int>,std::set<boost::shared_ptr<int>,std::less<boost::shared_pt r<int> >,std ::allocator<boost::shared_ptr<int> > >::_Kfn,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::iterator,bool>' being compiled c:\program files\microsoft visual studio\vc98\include\utility(25) : warning C4786: 'std::_Tree<boost::shared_array<char>,boost::shared_array<char> ,std::set<boost::shared_array<char>,std::less<boost::shared_array<char > >,std::allocator<boost::shared_ array<char> > >::_Kfn,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::iterator' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\libs\smart_ptr\smart_ptr_test.cpp(242) : see reference to class template instantiation 'std::pair<std::_Tree<boost::shared_array<char>,boost::s hared_array<char>,std::set<boost::shared_array<char>,std::less<boost:: shared_array <char> >,std::allocator<boost::shared_array<char> > >::_Kfn,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::iterator,bool>' being compiled c:\program files\microsoft visual studio\vc98\include\utility(21) : warning C4786: 'std::pair<std::_Tree<boost::shared_ptr<int>,boost::shared_ptr< int>,std::set<boost::shared_ptr<int>,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_pt r<int> > >::_Kfn,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::iterator,bool>::pair<std::_Tree<boost::shared_ptr<int>,boost::share d_ptr<int>,std::set<boost::shared_ptr<int>,std::less<boost::shared_ptr <int> >,std::allo cator<boost::shared_ptr<int> > >::_Kfn,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::iterator,bool>' : identifier was truncated to '255' characters in the debug information c:\program files\microsoft visual studio\vc98\include\utility(21) : warning C4786: 'std::pair<std::_Tree<boost::shared_array<char>,boost::shared_a rray<char>,std::set<boost::shared_array<char>,std::less<boost::shared_ array<char> >,std::allocator<boos t::shared_array<char> > >::_Kfn,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::iterator,bool>::pair<std::_Tree<boost::shared_array<char>,boost::sh ared_array<char>,std::set<boost::shared_array<char>,std::less<boos t::shared_array<char> >,std::allocator<boost::shared_array<char> > >::_Kfn,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::iterator,bool>' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_array<char>,boost::shared_array<char> ,std::set<boost::shared_array<char>,std::less<boost::shared_array<char > >,std::allocator<boost::shared_array<char> > >::_Kfn ,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::_Nil' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_array<char>,boost::shared_array<char> ,std::set<boost::shared_array<char>,std::less<boost::shared_array<char > >,std::allocator<boost::shared_array<char> > >::_Kfn ,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::_Nilrefs' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_ptr<int>,boost::shared_ptr<int>,std:: set<boost::shared_ptr<int>,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::_Kfn,std::less<boos t::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::_Nilrefs' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_array<char>,boost::shared_array<char> ,std::set<boost::shared_array<char>,std::less<boost::shared_array<char > >,std::allocator<boost::shared_array<char> > >::_Kfn ,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_array<char>,boost::shared_array<char> ,std::set<boost::shared_array<char>,std::less<boost::shared_array<char > >,std::allocator<boost::shared_array<char> > >::_Kfn ,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::const_iterator' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_array<char>,boost::shared_array<char> ,std::set<boost::shared_array<char>,std::less<boost::shared_array<char > >,std::allocator<boost::shared_array<char> > >::_Kfn ,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::iterator' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_array<char>,boost::shared_array<char> ,std::set<boost::shared_array<char>,std::less<boost::shared_array<char > >,std::allocator<boost::shared_array<char> > >::_Kfn ,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::_Node' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_array<char>,boost::shared_array<char> ,std::set<boost::shared_array<char>,std::less<boost::shared_array<char > >,std::allocator<boost::shared_array<char> > >::_Kfn ,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::_Redbl' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_ptr<int>,boost::shared_ptr<int>,std:: set<boost::shared_ptr<int>,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::_Kfn,std::less<boos t::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::const_iterator' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_ptr<int>,boost::shared_ptr<int>,std:: set<boost::shared_ptr<int>,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::_Kfn,std::less<boos t::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::iterator' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::_Tree<boost::shared_ptr<int>,boost::shared_ptr<int>,std:: set<boost::shared_ptr<int>,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::_Kfn,std::less<boos t::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::_Redbl' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::pair<std::_Tree<boost::shared_ptr<int>,boost::shared_ptr< int>,std::set<boost::shared_ptr<int>,std::less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::_Kfn,std: :less<boost::shared_ptr<int> >,std::allocator<boost::shared_ptr<int> > >::iterator,bool>' : identifier was truncated to '255' characters in the debug information c:\boost_1_29_0\boost\checked_delete.hpp(28) : warning C4786: 'std::pair<std::_Tree<boost::shared_array<char>,boost::shared_a rray<char>,std::set<boost::shared_array<char>,std::less<boost::shared_ array<char> >,std::allocator<boost::shared_array<char> > >::_Kfn,std::less<boost::shared_array<char> >,std::allocator<boost::shared_array<char> > >::iterator,bool>' : identifier was truncated to '255' characters in the debug information Linking... GRPostOffice.exe - 0 error(s), 17 warning(s) Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> . [Non-text portions of this message have been removed]

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RE: [Boost-Users] Extended use of BGL File Dependency Example
by Tom Matelich 01 Dec '02

01 Dec '02

> I was excited to get to use the graph library for a > dependency tracking tool > we needed, now I have a feature that I don't know how to do. This is > mapping library/executable dependencies and we have a lot of apps with > common sub-libraries. I'd like to extract a full-rebuild > order for only > certain nodes, i.e. what libs do I need to build for apps A > and B? Since > its a DAG, I thought something about reachability, perhaps? > I'm not too > familiar with graph theory :( Okay, so I solved that one with using a "depends on" relationship rather than "used by", then used a breadth_first_search. Now I have a tougher question, maybe I'll get an answer this time :). I'm trying to make my graphviz representation look nicer and I was wondering if there is an algorithm already for simplifying: -----B\ A--< \ --------C to: A---B---C of course this is happening on a much larger scale. Thanks for any input you might have, Tom pardon the disclaimer... ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

2 1

boost::iterator_adaptor
by Julia Donawald 01 Dec '02

01 Dec '02

Hi, I am trying to write my own iterator - class and using for that the boost::iterator_adaptor. I could find on the webpage several examples of how to connect an existing iterator like std::string::iterator or a simple array as "base-class" for my new iterator, but what can I do if I dont have any base-iterator? In the documentation I found the following sentence: "The Iterator Adaptor library allows you transform an arbitrary ``base'' type into a standard-conforming iterator with the behaviors you choose. Doing so is especially easy if the ``base'' type is itself an iterator." In my situation I dont have any base type which is an iterator, so how should I now create such a base-type? Which are the specifications of such a base-type? Where can I get information on how to create a new base-type? I am trying to write an iterator which reads records from a file or a database and always when I do the it++ the next record is read from the file or database. Thanks a lot in advance Julia

3 2

FW: [Boost-Users] Spirit build problems on msvc
by HartmutKaiser＠t-online.de 30 Nov '02

30 Nov '02

Holger Thiele wrote: > Spirit has been accepted into boost, so i guess this is the > correct group > for posting this question. > Trying to build the simplexml example, i get the following > output from msvc6 > sp5 > (and similar ones from msvc 7): > [sniped error messages] Not all features of spirit are supported for all compilers (yet). Please have a look at http://spirit.sourceforge.net/wiki/index.php?page=Compiler+Table, where you can find a list of supported compilers (which compiler can handle which sample/feature). Regards Hartmut PS: I took the liberty to forward your message to the spirit mailing list. > I downloaded the spirit-only-1.5.1.zip and included it in my > boost directory > tree. > > Any ideas?

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Spirit build problems on msvc
by Holger Thiele 29 Nov '02

29 Nov '02

Spirit has been accepted into boost, so i guess this is the correct group for posting this question. Trying to build the simplexml example, i get the following output from msvc6 sp5 (and similar ones from msvc 7): -------------------Configuration: simplexml - Win32 Debug-------------------- Compiling... ****** {BD Software Proxy CL v2.26} STL Message Decryption is Off ****** simplexml.cpp f:\swd\boost\boost\spirit\core\impl\primitives.ipp(88) : warning C4244: 'return' : conversion from 'int' to 'char', possible loss of data f:\swd\boost\boost\spirit\core\impl\primitives.ipp(89) : warning C4244: 'return' : conversion from 'int' to 'char', possible loss of data f:\swd\boost\boost\spirit\iterator\impl\msvc_ps_helper.hpp(60) : error C2371: 'true_t' : redefinition; different basic types f:\swd\boost\boost\spirit\core\basics.hpp(38) : see declaration of 'true_t' f:\swd\boost\boost\spirit\iterator\impl\msvc_ps_helper.hpp(65) : error C2371: 'false_t' : redefinition; different basic types f:\swd\boost\boost\spirit\core\impl\basics.ipp(23) : see declaration of 'false_t' f:\swd\boost\boost\spirit\iterator\impl\multi_pass_msvc.hpp(402) : fatal error C1903: unable to recover from previous error(s); stopping compilation Error executing cl.exe. I downloaded the spirit-only-1.5.1.zip and included it in my boost directory tree. Any ideas?

1 0

Date_Time library question...
by Luc Bergeron 29 Nov '02

29 Nov '02

Hello everyone, I was wondering, while looking at the source files, why the date_iterator doesn't provide an operator--() ??? I've added this in the "date_iterator.hpp" file : //--------------------------------------------------------- date_itr_base& operator--() { current_ = current_ - get_offset(current_); return *this; } //--------------------------------------------------------- I've rebuilt the library and done this little test : //--------------------------------------------------------- #include <iostream> #include <boost/date_time/gregorian/gregorian.hpp> int main(void) { using namespace boost::gregorian; date today = day_clock::local_day(); day_iterator ditr(today, 1); int nbDaysToIterate = 360; for (;nbDaysToIterate != 0; --ditr, --nbDaysToIterate) { std::cout << to_iso_extended_string(*ditr) << std::endl; } } //--------------------------------------------------------- Everything seems to run OK. I've checked the february month and it has a 28th... Now I wonder why wasn't it included in the release ??? Cheers. Luc Bergeron.

2 1

Using function_traits
by Marshall Clow 29 Nov '02

29 Nov '02

I'm trying to use the function traits to extract the return type of a template parameter, but it's not compiling. Any ideas what's wrong here? -------- begin simplified code ------ template<typename Proc> class CacheValue { typedef boost::function_traits<Proc>::R ReturnType; template<typename Arg1> ReturnType operator () ( Arg1 arg1 ) { /* do something */ } }; CacheValue<unsigned long (*) ( unsigned long )> aValue; -------- end simplified code ------ Gets the error: Error : illegal use of incomplete struct/union/class 'boost::detail::function_traits_helper<unsigned long (**)(unsigned long)>' (point of instantiation: 'main()') (instantiating: 'CacheValue<unsigned long (*)(unsigned long)>') (instantiating: 'boost::function_traits<unsigned long (*)(unsigned long)>') function_traits.hpp line 170 public detail::function_traits_helper<typename add_pointer<Function>::type> Error : 'R' is not a member of class 'boost::function_traits<unsigned long (*)(unsigned long)>' (point of instantiation: 'main()') (instantiating: 'CacheValue<unsigned long (*)(unsigned long)>') HelloWorld.cp line 57 CacheValue<TickGetter> ticks ( GetCount ); Environment: MacOS 10.2.2, CodeWarrior 8.3, boost from CVS this morning. It seems as if the "add_pointer" in function_traits_helper is messing things up. Of course, it's more likely that I am using this wrong ;-) Thanks in advance! -- -- Marshall Marshall Clow Idio Software <mailto:marshall@idio.com> Hey! Who messed with my anti-paranoia shot?

2 1

boost::iterator_adaptor
by Julia Donawald 29 Nov '02

29 Nov '02

Hi, I am trying to write my own iterator - class and using for that the boost::iterator_adaptor. I could find on the webpage several examples of how to connect an existing iterator like std::string::iterator or a simple array as "base-class" for my new iterator, but what can I do if I dont have any base-iterator? In the documentation I found the following sentence: "The Iterator Adaptor library allows you transform an arbitrary ``base'' type into a standard-conforming iterator with the behaviors you choose. Doing so is especially easy if the ``base'' type is itself an iterator." In my situation I dont have any base type which is an iterator ( as base type I have a simple int ), so how should I now create such a base-type? Which are the specifications of such a base-type? Where can I get information on how to create a new base-type? I am trying to write an iterator which reads records from a file or a database and always when I do the it++ the next record is read from the file or database. Bye, Julia

1 0

Re: [Boost-Users] ublas::matrix sharing storage with ublas::vecto r
by Stephen Crowley 28 Nov '02

28 Nov '02

On Thu, Nov 28, 2002 at 09:12:53AM -0500, Toon Knapen wrote: > On Wednesday 27 November 2002 20:46, Stephen Crowley wrote: > > What do you mean by "just use it as" ? > > > > For example.. I have a matrix<double> m(5,5); > > > > In some code I actually need to use it as a 5x5 matrix.. but other parts > > must reference it as a vector (to pass to another library). > > OK, So as to get to the bottom of this. Do you really want to perform vector > operations on a vector that consists of a concatenation of all rows (or > columns) of the matrix do you want to get access to the storage to pass your > information to another library. > > The latter case is dealt with in the boost-sandbox/boost/numeric/bindings. > There we've spend effort to be able to extract the begin- and end-pointer > (not iterator) from any vector or matrix. (In the bindings it's used to pass > these pointers to e.g. BLAS) > > In the former case, could you enlighten me what kind of numeric operations > you're dealing with ? The matrix I am working with is a set of weights for a neural net. I am using a kalman filtering library (http://www.acfr.usyd.edu.au/technology/bayesianfilter/Bayes++.htm) that treats the weights as a vector. So, I'm not really sure how to answer your question. I guess I would say that I need to access a vector as a concatenation of the rows or columns of the matirx (for this purpose it does not matter as long as it is consistent). However, copying undering data() member is working for now, although not as quickly as I would like. -- Stephen

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