July 2003 - Boost-users - lists.preview.boost.org

Random Number Generation
by tylersc111 23 Jul '03

23 Jul '03

I've got three questions/comments regarding the Random Number Library: Question (1) --------------------------------------------------------- How about including a facility for generating "antithetic random variates"? (Do a google search if the term is unfamiliar). A partial implementation might be something like the following, (I haven't tried compiling this, so please pardon any syntax errors...): template< class URNG > // Uniform Random Number Generator class antithetic { private: URNG urng; public: explicit antithetic( s ) { urng.seed(s); } // Perhaps not quite right (see question (2) below) typename URNG::result_type operator()() { return URNG::max_value - urng(); } }; Then one would be able to construct two antithetic variates (rng1 & rng2) as follows: mt19937 rng1(seed); antithetic<mt19937> rng2(seed); Question (2) -------------------------------------------------------- Regarding the "uniform_01" generator (and a possible bug in "uniform_in_sphere"). The interval generated by uniform_01 is designed to be the "half-open" interval [0,1). The asymmetry seems unnecessary. How about using the open interval (0,1). I can appreciate that perhaps efficiency is the reason for using the interval [0,1) if one is generating the random floating point numbers by setting the mantissa with a random bit stream. But, consider the following advantage to using (0,1): You would avoid a possible zerodivide in the "uniform_in_sphere" class. Here's my reasoning: Using the current "uniform_01" generator with the half open interval [0,1) the normal_distribution::operator() can return zero. Using my proposed "uniform_01" generator with the open interval (1,1) the normal_distribution::operator() will never return exactly zero. The "zero" return from normal_distribution::operator() could conceivably cause a zerodivide in "uniform_in_sphere". Question (3) -------------------------------------------------------- How about having a boost random number generator whose output would match that of Matlab's random number generator (both uniform and gaussian)? This would be useful in doing sanity tests when porting code to/from Matlab. Here's a link which gives some info on their generators: http://www.mathworks.com/support/solutions/data/8542.shtml

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Newbie missing a header for boost_date_time?
by dick.bridges＠tais.com 23 Jul '03

23 Jul '03

I must be missing one or more headers but I can't figure it out. Can someone help get me pointed in the right direction? <extract> #include "boost/date_time/gregorian/gregorian.hpp" #include "boost/date_time/posix_time/posix_time.hpp" using namespace boost::posix_time; using namespace boost::gregorian; date d(2002,Feb,1); </extract> <results> c:\boost\boost_1_30_0\boost\date_time\gregorian\greg_month.hpp(51) : warning C4244: 'argument' : conversion from 'boost::gregorian::greg_month::month_enum' to 'boost::CV::constrained_value<value_policies>::value_type', possible loss of data with [ value_policies=boost::gregorian::greg_month_policies ] c:\boost\boost_1_30_0\boost\date_time\gregorian\greg_date.hpp(77) : warning C4244: 'argument' : conversion from 'boost::gregorian::date_duration_rep' to 'boost::CV::constrained_value<value_policies>::value_type', possible loss of data with [ value_policies=boost::gregorian::greg_day_of_year_policies ] c:\boost\boost_1_30_0\boost\date_time\time_parsing.hpp(65) : warning C4267: 'initializing' : conversion from 'size_t' to 'int', possible loss of data c:\boost\boost_1_30_0\boost\iterator_adaptors.hpp(1409) : see reference to class template instantiation 'boost::filter_iterator_generator<Predicate,Iterator,Value,Reference,Pointer,Category,Distance>' being compiled c:\boost\boost_1_30_0\boost\date_time\time_duration.hpp(69) : warning C4244: 'return' : conversion from 'boost::date_time::time_resolution_traits<frac_sec_type,res,resolution_adjust,frac_digits>::fractional_seconds_type' to 'boost::date_time::time_duration<T,rep_type>::hour_type', possible loss of data with [ frac_sec_type=boost::int64_t, res=micro, resolution_adjust=0x0f4240, frac_digits=6 ] and [ T=boost::posix_time::time_duration, rep_type=boost::posix_time::time_res_traits ] c:\boost\boost_1_30_0\boost\date_time\time_duration.hpp(68) : while compiling class-template member function 'boost::date_time::time_duration<T,rep_type>::hour_type boost::date_time::time_duration<T,rep_type>::hours(void) const' with [ T=boost::posix_time::time_duration, rep_type=boost::posix_time::time_res_traits ] c: \boost\boost_1_30_0\boost\date_time\posix_time\posix_time_config.hpp(62) : see reference to class template instantiation 'boost::date_time::time_duration<T,rep_type>' being compiled with [ T=boost::posix_time::time_duration, rep_type=boost::posix_time::time_res_traits ] c:\boost\boost_1_30_0\boost\date_time\time_duration.hpp(74) : warning C4244: 'return' : conversion from 'boost::date_time::time_resolution_traits<frac_sec_type,res,resolution_adjust,frac_digits>::fractional_seconds_type' to 'boost::date_time::time_duration<T,rep_type>::min_type', possible loss of data with [ frac_sec_type=boost::int64_t, res=micro, resolution_adjust=0x0f4240, frac_digits=6 ] and [ T=boost::posix_time::time_duration, rep_type=boost::posix_time::time_res_traits ] c:\boost\boost_1_30_0\boost\date_time\time_duration.hpp(73) : while compiling class-template member function 'boost::date_time::time_duration<T,rep_type>::min_type boost::date_time::time_duration<T,rep_type>::minutes(void) const' with [ T=boost::posix_time::time_duration, rep_type=boost::posix_time::time_res_traits ] c:\boost\boost_1_30_0\boost\date_time\time_duration.hpp(79) : warning C4244: 'return' : conversion from 'boost::date_time::time_resolution_traits<frac_sec_type,res,resolution_adjust,frac_digits>::fractional_seconds_type' to 'boost::date_time::time_duration<T,rep_type>::sec_type', possible loss of data with [ frac_sec_type=boost::int64_t, res=micro, resolution_adjust=0x0f4240, frac_digits=6 ] and [ T=boost::posix_time::time_duration, rep_type=boost::posix_time::time_res_traits ] c:\boost\boost_1_30_0\boost\date_time\time_duration.hpp(78) : while compiling class-template member function 'boost::date_time::time_duration<T,rep_type>::sec_type boost::date_time::time_duration<T,rep_type>::seconds(void) const' with [ T=boost::posix_time::time_duration, rep_type=boost::posix_time::time_res_traits ] c:\boost\boost_1_30_0\boost\date_time\time_system_counted.hpp(39) : warning C4244: 'initializing' : conversion from 'boost::date_time::counted_time_rep<config>::int_type' to 'boost::date_time::gregorian_calendar_base<ymd_type_,date_int_type_>::date_int_type', possible loss of data with [ config=boost::posix_time::millisec_posix_time_system_config ] and [ ymd_type_=boost::gregorian::greg_year_month_day, date_int_type_=boost::date_time::int_adapter<unsigned long>::int_type ] c:\boost\boost_1_30_0\boost\date_time\time_system_counted.hpp(38) : while compiling class-template member function 'boost::date_time::counted_time_rep<config>::date_type boost::date_time::counted_time_rep<config>::date(void) const' with [ config=boost::posix_time::millisec_posix_time_system_config ] c:\boost\boost_1_30_0\boost\date_time\time_system_counted.hpp(72) : see reference to class template instantiation 'boost::date_time::counted_time_rep<config>' being compiled with [ config=boost::posix_time::millisec_posix_time_system_config ] c:\boost\boost_1_30_0\boost\date_time\time.hpp(48) : see reference to class template instantiation 'boost::date_time::counted_time_system<time_rep>' being compiled with [ time_rep=boost::posix_time::int64_time_rep ] c:\boost\boost_1_30_0\boost\date_time\posix_time\ptime.hpp(19) : see reference to class template instantiation 'boost::date_time::base_time<T,time_system>' being compiled with [ T=boost::posix_time::ptime, time_system=boost::posix_time::posix_time_system ] c:\boost\boost_1_30_0\boost\date_time\gregorian_calendar.ipp(120) : warning C4244: 'initializing' : conversion from 'unsigned long' to 'unsigned short', possible loss of data c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\streambuf(250) : while compiling class-template member function 'boost::date_time::gregorian_calendar_base<ymd_type_,date_int_type_>::ymd_type boost::date_time::gregorian_calendar_base<ymd_type_,date_int_type_>::from_day_number(boost::date_time::gregorian_calendar_base<ymd_type_,date_int_type_>::date_int_type)' with [ ymd_type_=boost::gregorian::greg_year_month_day, date_int_type_=boost::date_time::int_adapter<unsigned long>::int_type ] c: \boost\boost_1_30_0\boost\date_time\gregorian\greg_calendar.hpp(22) : see reference to class template instantiation 'boost::date_time::gregorian_calendar_base<ymd_type_,date_int_type_>' being compiled with [ ymd_type_=boost::gregorian::greg_year_month_day, date_int_type_=boost::date_time::int_adapter<unsigned long>::int_type ] c:\boost\boost_1_30_0\boost\date_time\gregorian_calendar.ipp(121) : warning C4244: 'initializing' : conversion from 'unsigned long' to 'unsigned short', possible loss of data c:\boost\boost_1_30_0\boost\date_time\gregorian_calendar.ipp(125) : warning C4244: 'argument' : conversion from 'boost::date_time::gregorian_calendar_base<ymd_type_,date_int_type_>::date_int_type' to 'unsigned short', possible loss of data with [ ymd_type_=boost::gregorian::greg_year_month_day, date_int_type_=boost::date_time::int_adapter<unsigned long>::int_type ] c:\boost\boost_1_30_0\boost\date_time\date_parsing.hpp(30) : warning C4244: 'argument' : conversion from 'int' to 'unsigned short', possible loss of data c:\boost\boost_1_30_0\boost\date_time\gregorian\parsers.hpp(17) : see reference to function template instantiation 'date_type boost::date_time::parse_date<boost::gregorian::date>(const std::string &)' being compiled with [ date_type=boost::gregorian::date ] c:\boost\boost_1_30_0\boost\date_time\date_parsing.hpp(31) : warning C4244: 'argument' : conversion from 'int' to 'unsigned short', possible loss of data c:\boost\boost_1_30_0\boost\date_time\date_parsing.hpp(32) : warning C4244: 'argument' : conversion from 'int' to 'unsigned short', possible loss of data c:\boost\boost_1_30_0\boost\date_time\date_parsing.hpp(54) : warning C4244: 'argument' : conversion from 'int' to 'unsigned short', possible loss of data c:\boost\boost_1_30_0\boost\date_time\gregorian\parsers.hpp(22) : see reference to function template instantiation 'date_type boost::date_time::parse_undelimited_date<boost::gregorian::date>(const std::string &)' being compiled with [ date_type=boost::gregorian::date ] c:\boost\boost_1_30_0\boost\date_time\date_parsing.hpp(55) : warning C4244: 'argument' : conversion from 'int' to 'unsigned short', possible loss of data c:\boost\boost_1_30_0\boost\date_time\date_parsing.hpp(56) : warning C4244: 'argument' : conversion from 'int' to 'unsigned short', possible loss of data c:\boost\boost_1_30_0\boost\date_time\time_parsing.hpp(103) : warning C4244: 'initializing' : conversion from 'int' to 'short', possible loss of data c:\boost\boost_1_30_0\boost\date_time\time_parsing.hpp(130) : see reference to function template instantiation 'time_duration boost::date_time::parse_undelimited_time_duration<time_duration>(const std::string &)' being compiled with [ time_duration=time_duration ] c: \boost\boost_1_30_0\boost\date_time\posix_time\time_parsers.hpp(26) : see reference to function template instantiation 'time_type boost::date_time::parse_iso_time<boost::posix_time::ptime>(const std::string &,char)' being compiled with [ time_type=boost::posix_time::ptime ] c:\boost\boost_1_30_0\boost\lexical_cast.hpp(147) : warning C4800: 'void *' : forcing value to bool 'true' or 'false' (performance warning) c:\boost\boost_1_30_0\boost\lexical_cast.hpp(146) : while compiling class-template member function 'bool boost::detail::lexical_stream<Target,Source>::operator <<(const Source &)' with [ Target=int, Source=boost::token_iterator_generator<boost::char_delimiters_separator<char>,std::basic_string<char,std::char_traits<char>,std::allocator<char>>::const_iterator,std::string>::value_type ] c:\boost\boost_1_30_0\boost\lexical_cast.hpp(189) : see reference to class template instantiation 'boost::detail::lexical_stream<Target,Source>' being compiled with [ Target=int, Source=boost::token_iterator_generator<boost::char_delimiters_separator<char>,std::basic_string<char,std::char_traits<char>,std::allocator<char>>::const_iterator,std::string>::value_type ] c:\boost\boost_1_30_0\boost\date_time\date_parsing.hpp(28) : see reference to function template instantiation 'Target boost::lexical_cast<int,boost::token_iterator_generator<TokenizerFunc,Iterator,Type>::value_type>(Source)' being compiled with [ Target=int, TokenizerFunc=boost::char_delimiters_separator<char>, Iterator=std::basic_string<char,std::char_traits<char>,std::allocator<char>>::const_iterator, Type=std::string, Source=boost::token_iterator_generator<boost::char_delimiters_separator<char>,std::basic_string<char,std::char_traits<char>,std::allocator<char>>::const_iterator,std::string>::value_type ] c:\boost\boost_1_30_0\boost\date_time\gregorian\parsers.hpp(17) : see reference to function template instantiation 'date_type boost::date_time::parse_date<boost::gregorian::date>(const std::string &)' being compiled with [ date_type=boost::gregorian::date ] c:\boost\boost_1_30_0\boost\lexical_cast.hpp(147) : error C2679: binary ' <<' : no operator found which takes a right-hand operand of type 'const boost::token_iterator_generator<TokenizerFunc,Iterator,Type>::value_type' (or there is no acceptable conversion) with [ TokenizerFunc=boost::char_delimiters_separator<char>, Iterator=std::basic_string<char,std::char_traits<char>,std::allocator<char>>::const_iterator, Type=std::string ] c:\boost\boost_1_30_0\boost\lexical_cast.hpp(146) : while compiling class-template member function 'bool boost::detail::lexical_stream<Target,Source>::operator <<(const Source &)' with [ Target=unsigned short, Source=boost::token_iterator_generator<boost::char_delimiters_separator<char>,std::basic_string<char,std::char_traits<char>,std::allocator<char>>::const_iterator,std::string>::value_type ] c:\boost\boost_1_30_0\boost\lexical_cast.hpp(189) : see reference to class template instantiation 'boost::detail::lexical_stream<Target,Source>' being compiled with [ Target=unsigned short, Source=boost::token_iterator_generator<boost::char_delimiters_separator<char>,std::basic_string<char,std::char_traits<char>,std::allocator<char>>::const_iterator,std::string>::value_type ] c:\boost\boost_1_30_0\boost\date_time\time_parsing.hpp(30) : see reference to function template instantiation 'Target boost::lexical_cast<unsigned short,boost::token_iterator_generator<TokenizerFunc,Iterator,Type>::value_type>(Source)' being compiled with [ Target=unsigned short, TokenizerFunc=boost::char_delimiters_separator<char>, Iterator=std::basic_string<char,std::char_traits<char>,std::allocator<char>>::const_iterator, Type=std::string, Source=boost::token_iterator_generator<boost::char_delimiters_separator<char>,std::basic_string<char,std::char_traits<char>,std::alloca tor<char>>::const_iterator,std::string>::value_type ] c: \boost\boost_1_30_0\boost\date_time\posix_time\time_parsers.hpp(18) : see reference to function template instantiation 'time_duration boost::date_time::parse_delimited_time_duration<boost::posix_time::time_duration>(const std::string &)' being compiled with [ time_duration=boost::posix_time::time_duration ] Build log was saved at "file://c:\dev\AuthStorm\Debug\BuildLog.htm" AuthStorm - 1 error(s), 18 warning(s) ---------------------- Done ---------------------- Build: 0 succeeded, 1 failed, 0 skipped </results>

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Is there a boost_date_time dll?
by dick.bridges＠tais.com 23 Jul '03

23 Jul '03

Development environment is .NET 2003 (i.e., VC7.1). I'm reasonably sure there were no errors when I built boost_1_30_0. \boost_1_30_0\libs\date_time\build\bin\boost_date_time.dll certainly exists - but it's a directory that contains a subdirectory (. \vc7\debug\runtime-link-dynamic) that contains a .CMD, .pdb and two .obj files. As the old saying goes: "I can see fine - I just don't understand what I'm looking at." I'm clearly having a "senior moment" but honestly: I searched boost.org, google.com and [even] altavista.com/web/adv. Any pointers to get me back on the right track would be appreciated.

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RE: [Boost-Users] Problem with regular expression
by James Zappia 23 Jul '03

23 Jul '03

You need to escape the backslash in your exp variable. Here's (1) that works. #include <iostream> #include <string> #include <boost/regex.hpp> using namespace std; using namespace boost; int main() { regex exp("\\s(ab)*", regbase::perl); // note the escaped \s here cmatch what; if ( regex_match(" ababab", what, exp) ) { string str = what[0]; cout << str << endl; } } Regards, James -----Original Message----- From: Javier de Acha [mailto:jdeacha@corest.com] Sent: Wednesday, July 23, 2003 10:50 AM To: Boost-Users(a)yahoogroups.com Subject: [Boost-Users] Problem with regular expression Hello, The next few lines doesn't work (1) with \s. But (2) works well [[:space:]] regbase::escape_in_lists dont func? Someone it knows because? Thanks Javier --------------------------------------------------------------------- (1) void main() { regex exp("\s(ab)*",regbase::perl); cmatch what; if(regex_match(" ababab", what, exp)) { string str = what[0]; //this fail } } ---------------------------------------------------------------------------- ---- (2) void main() { regex exp("[[:space:]](ab)*",regbase::perl); cmatch what; if(regex_match(" ababab", what, exp)) { string str = what[0]; //this succesfully match } } [Non-text portions of this message have been removed] ------------------------ Yahoo! Groups Sponsor ---------------------~--> Buy Ink Cartridges & Refill Kits for Your Epson at Myinks.com Free shipping on orders $50 or more to the US and Canada. http://www.c1tracking.com/l.asp?cid=5705&lp=home/epson.asp http://us.click.yahoo.com/brYXfA/_xWGAA/ySSFAA/EbFolB/TM ---------------------------------------------------------------------~-> 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] date-time library and ispunct() ambiguity under MSVC6
by Jeff Garland 23 Jul '03

23 Jul '03

Carl wrote: > I get the following compilation error for this simple program under MSVC6: > > ************** test.cpp****************** > #include <iostream> > #include "boost/date_time/gregorian/gregorian.hpp" > > int main() > { > using namespace std; > > cout << ispunct(',') << endl; > > return 0; > } > > ************************************ > > error: > --------------------Configuration: names_test - Win32 > Debug-------------------- > Compiling... > test.cpp > c:\documents and settings\waldbcar.waldbcar\my documents\my > projects\vc\test\names_test\test.cpp(8) : error C2668: 'ispunct' : > ambiguous call to overloaded function > Error executing cl.exe. > > test.obj - 1 error(s), 0 warning(s) > > been dumped into the global namespace by default. However, it seems like > the date-time library must be doing something like: > > namespace std > { > using ::ispunct; > } > > somewhere in its internals (or maybe just using something else that does?). This isn't done directly in date-time. I'm guessing that it might have something to do with 'tokenizer' library which date-time uses for parsing. See boost/token_function.hpp for some ispunct magic that is likely at the root of this issue. HTH, Jeff

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weak_ptr
by Jason Winnebeck 23 Jul '03

23 Jul '03

Is there a reason why weak_ptr's cannot be compared with ==, or tested in a conditional? If I have two weak_ptr's, I thought it to be strange that I have to do: (w1.lock() == w2.lock()) And to test if a weak_ptr is the empty weak_ptr: if ( !(w1.lock()) ) which seems kind of awkward. Looking at the implementation, I see how the copy constructor is defined using lock. I understand what the comments are saying there. Perhaps there are some multithreaded issues that prevent equality testing I don't see. I would like the semantics that w1 and w2 compare to be equal whether or not the object they are pointing to are valid or not. I'm not sure if weak_ptrs become "empty" when the object they point to is destroyed (because there's no way to test for "emptyness" or "nullness" of a weak_ptr), but if they do I can see how the equality test can't work, but not the conditional test. Even so, why is there not an operator == provided that locks both weak_ptr? Is it acceptable (the documentation didn't make it clear to me), to use if ( w1.expired() ) to test if simply if w1 is "null" or "reset". What I am trying to do is have a "current" pointer that takes the value of something I want to be set (or note the fact that nothing is set), but I don't care if the object dies while that pointer is set -- in fact I don't want to keep it alive because I don't have an easy way to call reset on current were I to make it a shared_ptr. Jason

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date-time library and ispunct() ambiguity under MSVC6
by Carl Waldbieser 23 Jul '03

23 Jul '03

I get the following compilation error for this simple program under MSVC6: ************** test.cpp****************** #include <iostream> #include "boost/date_time/gregorian/gregorian.hpp" int main() { using namespace std; cout << ispunct(',') << endl; return 0; } ************************************ error: --------------------Configuration: names_test - Win32 Debug-------------------- Compiling... test.cpp c:\documents and settings\waldbcar.waldbcar\my documents\my projects\vc\test\names_test\test.cpp(8) : error C2668: 'ispunct' : ambiguous call to overloaded function Error executing cl.exe. test.obj - 1 error(s), 0 warning(s) Normally, this sort of thing would not be a problem, as I typically would just be using the qualified std::ispunct() instead of a using directive. However, this problem cropped up when I was trying to use the date-time library in conjuction with the Spirit parsing library. Spirit implements some function by doing exactly what I did in the above sample-- using a using directive and then calling ispunct() unqualified. I am guessing the ratonale behind this might have something to do with the fact that under MSVC6, functions like ispunct() (and most or all of <ccytpe>) seem to have been dumped into the global namespace by default. However, it seems like the date-time library must be doing something like: namespace std { using ::ispunct; } somewhere in its internals (or maybe just using something else that does?). Anyway, it seems to be a shame that I can't get these two great libraries to work together on my compiler. Is there any chance that someone out there might have a solution? Carl Waldbieser waldbie<at-sign>attglobal.net

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boost::date_time + setting system clock
by ericd 22 Jul '03

22 Jul '03

afternoon all, I was wondering if it is possible to set the clock using date_time. I been looking but have found no clue that it is so. From what I have seen so far, this library does a lot of cool stuff, and why not this. I am working on a little personal project that uses an ORB. The idea is to have all clocks synchronized. I have one machine that queries an atomic time server. After having done so it will call each machine and synchronize them. I am currently running a mix of Linux, Solaris, WIN NT 2000 and XP... and it freaks me out not to have them synchronized. Any help would be appreciated... Eric

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problem building boost on solaris
by jerry_karlin 22 Jul '03

22 Jul '03

gcc-Link-action libs/test/build/bin/libboost_prg_exec_monitor.so/g cc/debug/runtime-link-static/shared-linkable-true/ threading-single/libboost_prg_exec_monitor.so ld: warning: option -d appears more than once, first setting taken ld: fatal: option -dn and -z[text|textwarn|textoff] are incompatible ld: fatal: option -dn and -G are incompatible ld: fatal: Flags processing errors collect2: ld returned 1 exit status What's causing this, and how do I fix it? I can't figure my way through these jam files just yet... Sparc Solaris 2.7, gcc-2.95.3, binutils-2.14 Any help would be... helpful. Thanks!

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Defect in intrusive_ptr.hpp
by Ilya Chvetsov(work) 22 Jul '03

22 Jul '03

Hi! It seems to me, that the following string should be inserted to intrusive_ptr.hpp <string> #include <boost/config.hpp> </string> Following code can not be compiled without this string under MSVC6SP5(with STLPort) <code> # if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, <= 1200 && __SGI_STL_PORT) // MSVC6 has problems finding std::basic_ostream through the using declaration in namespace _STL using std::basic_ostream; template<class E, class T, class Y> basic_ostream<E, T> & operator<< (basic_ostream<E, T> & os, intrusive_ptr<Y> const & p) # else template<class E, class T, class Y> std::basic_ostream<E, T> & operator<< (std::basic_ostream<E, T> & os, intrusive_ptr<Y> const & p) # endif { os << p.get(); return os; } </code> -Ilya

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