October 2011 - Boost-users - lists.preview.boost.org

math tools roots
by Matwey V. Kornilov 11 Oct '11

11 Oct '11

Hi all, I believe that there is a bug in eps_tolerance implementation. At line 34 of toms748_solve.hpp one can see: return (fabs(a - b) / (std::min)(fabs(a), fabs(b))) <= eps; When both a and b equal zero this condition is evaluated to a false instead of a true. Left hand of condition is NaN and the right one is a floating- point number hence the result is false. Well obviously, a user wants to see true here because the relative length of interval in this case tend to zero.

10 13

Re: [Boost-users] What about achieving strong erection?
by Daniel Bradburn 11 Oct '11

11 Oct '11

..Stop difficulty sleeping and a loss of appetite! http://fuhes.the-best-web-sites.com/com.friend.php?tonid_hotmail=83v3

1 0

testing command-line interface using Boost.Test
by Olaf Meeuwissen 11 Oct '11

11 Oct '11

Dear all, I've been using Boost.Test with Test First and TTD approaches to library development and am one happy hacker. All tests are integrated with our continuous integration setup so we get test reports with every build. Now I'm starting on a few command-line utilities and would like to use Boost.Test to do the same. I have something simple going now with a test fixture to help with redirecting standard input, output and error and running commands in a way that the test runner does not hang when a command-line invocation returns a failure status. The gist of my tests would be as follows when testing the GNU coreutils `true` and `false` utilities BOOST_AUTO_TEST_CASE (test_false) { BOOST_CHECK_EQUAL (EXIT_FAILURE, my_system ("false")); } BOOST_AUTO_TEST_CASE (test_true) { BOOST_CHECK_EQUAL (EXIT_SUCCESS, my_system ("true")); } where my_system() basically does explicitly what system() would do for you. See [1] for an implementation of my_system(). When using system() instead of my_system(), the test runner fails the first test incorrectly(!) and hangs. It starts but never finishes the second test. Using my_system() the first tests still incorrectly fails but now at least the second tests completes and succeeds as expected. The first test produces unknown location(0): fatal error in "test_false": child has exited; pid: 19788; uid: 1000; exit value: 1 and I assume it never gets to the comparison that BOOST_CHECK_EQUAL() is supposed to do. Any suggestions on how to get this to work? Maybe even alternative approaches to testing command-line interfaces? [1] http://www.gnu.org/software/libc/manual/html_node/Process-Creation-Example.… Thanks in advance, -- Olaf Meeuwissen, LPIC-2 FLOSS Engineer -- AVASYS CORPORATION FSF Associate Member #1962 Help support software freedom http://www.fsf.org/jf?referrer=1962

3 14

Boost.Thread and thread-priority
by Andrej van der Zee 11 Oct '11

11 Oct '11

Hi, I have a question about thread priority in combination with Boost.Thread. I implemented a pool of threads that reads data-pkts from a work-queue in user-space. The main-thread receives data-packets from the kernel, copies them into user-space and places them in this data-queue. It is important that the kernel buffers do not overflow and therefor I thought raising the priority of the main-thread is a good idea. My question is would this *really* help? And how do I change priority with Boost.Thread? Cheers, Andrej

2 1

Problems installing boost 1.47.0
by Allan Nielsen 10 Oct '11

10 Oct '11

Hi I'm trying to install boost 1.47 in a single threaded edition but it does not seems to work. Here is what I tried: ./bootstrap.sh --without-icu --without-libraries=graph_parallel,mpi,python ./b2 threading=single --layout=system --prefix=/usr/local Here is the error I got on the second command: Building the Boost C++ Libraries. Performing configuration checks - has_icu builds : yes - ../config//has_gcc_visibility builds : yes - ../config//has_long_double_support builds : yes /storage/src/boost_1_47_0/tools/build/v2/build/virtual-target.jam:1079: in virtual-target.register-actual-name from module virtual-target error: Duplicate name of actual target: <pstage/lib>libboost_system.so.1.47.0 error: previous virtual target { common%common.copy-libboost_system.so.1.47.0.SHARED_LIB { gcc%gcc.link.dll-libboost_system.so.1.47.0.SHARED_LIB { gcc%gcc.compile.c++-error_code.o.OBJ { error_code.cpp.CPP } } } } error: created from ./stage-proper error: another virtual target { common%common.copy-libboost_system.so.1.47.0.SHARED_LIB { gcc%gcc.link.dll-libboost_system.so.1.47.0.SHARED_LIB { gcc%gcc.compile.c++-error_code.o.OBJ { error_code.cpp.CPP } } } } error: created from ./stage-proper error: added properties: <threading>single <warnings>on error: removed properties: <threading>multi <warnings>all /storage/src/boost_1_47_0/tools/build/v2/build/virtual-target.jam:490: in actualize-no-scanner from module object(file-target)@2784 /storage/src/boost_1_47_0/tools/build/v2/build/virtual-target.jam:135: in object(file-target)(a)2784.actualize from module object(file-target)@2784 /storage/src/boost_1_47_0/tools/build/v2/build-system.jam:749: in load from module build-system /storage/src/boost_1_47_0/tools/build/v2/kernel/modules.jam:283: in import from module modules /storage/src/boost_1_47_0/tools/build/v2/kernel/bootstrap.jam:142: in boost-build from module /storage/src/boost_1_47_0/boost-build.jam:17: in module scope from module Is there anything I can do to fix this locally ?? Best regards Allan W. Nielsen

4 8

Building boost with stlport?
by Robert Dailey 10 Oct '11

10 Oct '11

Hello, I was searching around Google for this but I wasn't able to find any documentation. Is there a way to reliably build the latest version of Boost using STLport on Windows instead of letting boost use Microsoft's STL implementation? Thanks in advance. --------- Robert Dailey

2 4

Variant stream output of ICU UnicodeString
by André 10 Oct '11

10 Oct '11

Hi, I'm trying to stream a Boost::Variant with << to std::cout but when I include an UnicodeString member from the ICU Unicode library the compiler doesn't recognices my overloaded operator<< for the UnicodeString. Here is a test program: #include <iostream> #include <unicode/unistr.h> #include <boost/variant.hpp> class Foo {}; std::ostream& operator<<(std::ostream& stream, Foo const &b) { return stream << "Foo"; } std::ostream& operator<<(std::ostream& stream, UnicodeString const & unicode) { return stream << "Unicode"; } int main() { boost::variant<Foo, UnicodeString, int, double> test; test = Foo(); std::cout << test << std::endl; test = "Hello World"; std::cout << test << std::endl; return 0; } Without the UnicodeString code everything works find but with it I get the following errors: g++ -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/TestUnicode.d" -MT"src/TestUnicode.d" -o "src/TestUnicode.o" "../src/TestUnicode.cpp" In file included from /usr/include/boost/variant/variant.hpp:1859, from /usr/include/boost/variant.hpp:17, from ../src/TestUnicode.cpp:11: /usr/include/boost/variant/detail/variant_io.hpp: In member function ‘void boost::detail::variant::printer<OStream>::operator()(const T&) const [with T = icu_4_2::UnicodeString, OStream = std::basic_ostream<char, std::char_traits<char> >]’: /usr/include/boost/variant/variant.hpp:825: instantiated from ‘typename Visitor::result_type boost::detail::variant::invoke_visitor<Visitor>::internal_visit(T&, int) [with T = const icu_4_2::UnicodeString, Visitor = boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > >]’ /usr/include/boost/variant/detail/visitation_impl.hpp:126: instantiated from ‘typename Visitor::result_type boost::detail::variant::visitation_impl_invoke_impl(int, Visitor&, VoidPtrCV, T*, mpl_::true_) [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, T = boost::detail::variant::visitation_impl(int, int, Visitor&, VoidPtrCV, mpl_::false_, NoBackupFlag, Which*, step0*) [with Which = boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor_impl(int, int, Visitor&, VoidPtrCV) [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, T0_ = Foo, T1 = icu_4_2::UnicodeString, T2 = int, T3 = double, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_]::first_which, step0 = boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor_impl(int, int, Visitor&, VoidPtrCV) [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, T0_ = Foo, T1 = icu_4_2::UnicodeString, T2 = int, T3 = double, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_]::first_step, Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, NoBackupFlag = boost::variant<Foo, icu_4_2::UnicodeString, int, double, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_>::has_fallback_type_]::T1]’ /usr/include/boost/variant/detail/visitation_impl.hpp:169: instantiated from ‘typename Visitor::result_type boost::detail::variant::visitation_impl_invoke(int, Visitor&, VoidPtrCV, T*, NoBackupFlag, int) [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, T = boost::detail::variant::visitation_impl(int, int, Visitor&, VoidPtrCV, mpl_::false_, NoBackupFlag, Which*, step0*) [with Which = boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor_impl(int, int, Visitor&, VoidPtrCV) [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, T0_ = Foo, T1 = icu_4_2::UnicodeString, T2 = int, T3 = double, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_]::first_which, step0 = boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor_impl(int, int, Visitor&, VoidPtrCV) [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, T0_ = Foo, T1 = icu_4_2::UnicodeString, T2 = int, T3 = double, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_]::first_step, Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, NoBackupFlag = boost::variant<Foo, icu_4_2::UnicodeString, int, double, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_>::has_fallback_type_]::T1, NoBackupFlag = boost::variant<Foo, icu_4_2::UnicodeString, int, double, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_>::has_fallback_type_]’ /usr/include/boost/variant/detail/visitation_impl.hpp:256: instantiated from ‘typename Visitor::result_type boost::detail::variant::visitation_impl(int, int, Visitor&, VoidPtrCV, mpl_::false_, NoBackupFlag, Which*, step0*) [with Which = boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor_impl(int, int, Visitor&, VoidPtrCV) [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, T0_ = Foo, T1 = icu_4_2::UnicodeString, T2 = int, T3 = double, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_]::first_which, step0 = boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor_impl(int, int, Visitor&, VoidPtrCV) [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, T0_ = Foo, T1 = icu_4_2::UnicodeString, T2 = int, T3 = double, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_]::first_step, Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, NoBackupFlag = boost::variant<Foo, icu_4_2::UnicodeString, int, double, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_>::has_fallback_type_]’ /usr/include/boost/variant/variant.hpp:1769: instantiated from ‘static typename Visitor::result_type boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor_impl(int, int, Visitor&, VoidPtrCV) [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, VoidPtrCV = const void*, T0_ = Foo, T1 = icu_4_2::UnicodeString, T2 = int, T3 = double, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_]’ /usr/include/boost/variant/variant.hpp:1791: instantiated from ‘typename Visitor::result_type boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::internal_apply_visitor(Visitor&) const [with Visitor = boost::detail::variant::invoke_visitor<boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > > >, T0_ = Foo, T1 = icu_4_2::UnicodeString, T2 = int, T3 = double, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_]’ /usr/include/boost/variant/variant.hpp:1813: instantiated from ‘typename Visitor::result_type boost::variant<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19>::apply_visitor(Visitor&) const [with Visitor = boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > >, T0_ = Foo, T1 = icu_4_2::UnicodeString, T2 = int, T3 = double, T4 = boost::detail::variant::void_, T5 = boost::detail::variant::void_, T6 = boost::detail::variant::void_, T7 = boost::detail::variant::void_, T8 = boost::detail::variant::void_, T9 = boost::detail::variant::void_, T10 = boost::detail::variant::void_, T11 = boost::detail::variant::void_, T12 = boost::detail::variant::void_, T13 = boost::detail::variant::void_, T14 = boost::detail::variant::void_, T15 = boost::detail::variant::void_, T16 = boost::detail::variant::void_, T17 = boost::detail::variant::void_, T18 = boost::detail::variant::void_, T19 = boost::detail::variant::void_]’ /usr/include/boost/variant/detail/variant_io.hpp:85: instantiated from ‘std::basic_ostream<_CharT, _Traits>& boost::operator<<(std::basic_ostream<_CharT, _Traits>&, const boost::variant<U0, U1, U2, U3, U4, U5, U6, U7, U8, U9, U10, U11, U12, U13, U14, U15, U16, U17, U18, U19>&) [with E = char, T = std::char_traits<char>, U0 = Foo, U1 = icu_4_2::UnicodeString, U2 = int, U3 = double, U4 = boost::detail::variant::void_, U5 = boost::detail::variant::void_, U6 = boost::detail::variant::void_, U7 = boost::detail::variant::void_, U8 = boost::detail::variant::void_, U9 = boost::detail::variant::void_, U10 = boost::detail::variant::void_, U11 = boost::detail::variant::void_, U12 = boost::detail::variant::void_, U13 = boost::detail::variant::void_, U14 = boost::detail::variant::void_, U15 = boost::detail::variant::void_, U16 = boost::detail::variant::void_, U17 = boost::detail::variant::void_, U18 = boost::detail::variant::void_, U19 = boost::detail::variant::void_]’ ../src/TestUnicode.cpp:27: instantiated from here /usr/include/boost/variant/detail/variant_io.hpp:64: error: no match for ‘operator<<’ in ‘((const boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > >*)this)->boost::detail::variant::printer<std::basic_ostream<char, std::char_traits<char> > >::out_ << operand’ /usr/include/c++/4.4/ostream:108: note: candidates are: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>& (*)(std::basic_ostream<_CharT, _Traits>&)) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:117: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ios<_CharT, _Traits>& (*)(std::basic_ios<_CharT, _Traits>&)) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:127: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::ios_base& (*)(std::ios_base&)) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:165: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long int) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:169: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long unsigned int) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:173: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(bool) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/bits/ostream.tcc:91: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(short int) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:180: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(short unsigned int) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/bits/ostream.tcc:105: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(int) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:191: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(unsigned int) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:200: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long long int) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:204: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long long unsigned int) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:209: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(double) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:213: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(float) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:221: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(long double) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/ostream:225: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(const void*) [with _CharT = char, _Traits = std::char_traits<char>] /usr/include/c++/4.4/bits/ostream.tcc:119: note: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_streambuf<_CharT, _Traits>*) [with _CharT = char, _Traits = std::char_traits<char>] I'm using gcc 4.4.5 on Ubuntu 11.04 and boost 1.42. Does someone know why the overloaded operator isn't used or how I can get the test program to work?

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boost multithread deisign for large and fast data exchange
by Jack Bryan 10 Oct '11

10 Oct '11

Hi, I am doing C++ multithreaded coding on Linux. Each thread hold some messagers, who need to talk (exchange message) to other messagers. Each messager is not only a message pruducer but also a message consumer. If a messager needs to talk to another messager and both of them are held by the same thread , that is intra-hread talk. Otherwise, it is inter-thread talk. A messager can generate multiple messages, each of which has a distinct message-receiver ID. Each messager needs to do some computing tasks in order to produce a message. Only the messager with match ID can receive and consume the message. All messagers work asynchronously and the message exchange (like a multicast) pairs are fixed and do not change in the whole process of the program. In order to simulate the above message exchange, I want to associate a priority message queue with each thread such that (1) Each messager in a priority queue is an element. Whenever a messager's computing task is done and its message is ready for sending out, it has the highest priority and it is poped out and saved in a map with the messager's receiver ID as key. (2) Then, the messager is push backed to the queue again and wait for receiving messgae from its talk pairs and do the above step (1). (3) each thread is associated with a queue like this. Sometimes, do inter-thread talk and some times do intra-thread talk. My questions: How to efficiently implement the above idea with boost data containers, thread, thread pool, boost algorithm or other boost components ? Are there other better ways to simulate the talk ? Any help, advice or idea is really appreciated. Thanks

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how to free thread object
by davieyan 10 Oct '11

10 Oct '11

Hi, I write code to start a thread,but how to free this thread. code: void helloworld() { std::cout << "Hello World!" << std::endl; } int main() { boost::thread thrd(&helloworld); thrd.join(); } -- View this message in context: http://boost.2283326.n4.nabble.com/how-to-free-thread-object-tp3888900p3888… Sent from the Boost - Users mailing list archive at Nabble.com.

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[graph] [beginner] How to use the "tie(...) feature" with standard c++ containers?
by Christoph 10 Oct '11

10 Oct '11

Hi recently i started programming with the boost graph library. You can use nice syntax for iterating over a set of vertices or edges by writing for example: //begin program #include <iostream> #include <boost/graph/adjacency_list.hpp> typedef boost::adjacency_list < boost::listS, boost::vecS, boost::bidirectionalS> my_graph; typedef boost::graph_traits <my_graph> my_graph_traits; int main() { my_graph g(5); my_graph_traits::vertex_iterator vi, vi_end; for (boost::tie (vi, vi_end) = vertices (g); vi != vi_end; ++vi) { std::cout << "vertex: " << *vi << std::endl; } } //End program Outputs: vertex: 0 vertex: 1 vertex: 2 vertex: 3 vertex: 4 My question is now how to define functions 'tie(...)' and 'elements(...)' for using them with standard containers. Suppose you have a container like the list: std::list <unsigned int> list(4); Now to iterate over all elements i would like to write something like //begin snippet std::list <unsigned int>::iterator begin, end; for (tie (begin, end) = elements (list); begin != end; ++begin) ;// do some thing //end snippet In stead of writing: //begin snippet begin = list.begin(); end = list.end(); for (; begin != end; ++begin) ;// do some thing //end snippet I started defining the function elements(...) like this: template <typename T> std::pair < typename T::iterator, typename T::iterator> elements (T container) { return std::make_pair(container.begin(), container.end()); } The compiler tells me, that 'tie' was not declared in this scope. So i assume that i also have to define the 'tie' function in some way. Maybe there is already some functionality to access the standard containers the way you can do it with 'tie' or maybe you could give me some hint to solve the problem. best regards Christoph

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