January 2006 - Boost-users - lists.preview.boost.org

Merrill Cornish: "Re: Boost.Serialization // Basic Usage Problem for your help!"
by Feng Wang 03 Jan '06

03 Jan '06

Merrill, I tried to change the include files order as you suggested, but it does not work. Any more suggestions? Feng

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Boost.Serialization // Basic Usage Problem for your help!
by Feng Wang 03 Jan '06

03 Jan '06

Dear All, I got a trouble with boost::serialization library and need your help. 1) I am working with FC4 on my laptop. GCC 4.0.2 is known handle this library pretty well according to yesterdays's report. http://boost.sourceforge.net/regression-logs/cs-Linux.html 2) try to test the basic sample obtained on webpage posted by Jeff Cogswell: #include <fstream> #include <iostream> //#include <boost/serialization/base_object.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/detail/basic_iarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/utility.hpp> #include <boost/serialization/access.hpp> using namespace std; class Vertex { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & x; ar & y; } double x; double y; public: Vertex() {} // Serialization requires a default constructor Vertex(double newX, double newY) : x(newX), y(newY) {} double getX() const { return x; } double getY() const { return y; } void dump() { cout << x << " " << y << endl; } }; int main() { Vertex v1(1.5, 2.5); std::ofstream ofs("myfile.vtx"); boost::archive::text_oarchive oa(ofs); oa << v1; ofs.close(); return 0; } 3) try to compile and link it by the following command: g++ -lboost_serialization testoa.cpp -otestoa and got a bunch of errors. 4) The errors looks as this: /tmp/ccS4C1Wt.o(.gnu.linkonce.r._ZTIN5boost7archive6detail15common_oarchiveINS0_13text_oarchiveEEE[typeinfo for boost::archive::detail::common_oarchive<boost::archive::text_oarchive>]+0x10): undefined reference to `typeinfo for boost::archive::detail::basic_oarchive' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost13serialization6detail27extended_type_info_typeid_0C2Ev[boost::serialization::detail::extended_type_info_typeid_0::extended_type_info_typeid_0()]+0x7): In function `boost::serialization::detail::extended_type_info_typeid_0::extended_type_info_typeid_0()': testoa.cpp: undefined reference to `boost::serialization::detail::extended_type_info_typeid_0::type_info_key' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive6detail15common_oarchiveINS0_13text_oarchiveEED2Ev[boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::~common_oarchive()]+0x18): In function `boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::~common_oarchive()': testoa.cpp: undefined reference to `boost::archive::detail::basic_oarchive::~basic_oarchive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive18text_oarchive_implINS0_13text_oarchiveEED0Ev[boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::~text_oarchive_impl()]+0x3d): In function `boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::~text_oarchive_impl()': testoa.cpp: undefined reference to `boost::archive::basic_text_oprimitive<std::basic_ostream<char, std::char_traits<char> > >::~basic_text_oprimitive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive18text_oarchive_implINS0_13text_oarchiveEED0Ev[boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::~text_oarchive_impl()]+0x69):testoa.cpp: undefined reference to `boost::archive::basic_text_oprimitive<std::basic_ostream<char, std::char_traits<char> > >::~basic_text_oprimitive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive18text_oarchive_implINS0_13text_oarchiveEED1Ev[boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::~text_oarchive_impl()]+0x3d): In function `boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::~text_oarchive_impl()': testoa.cpp: undefined reference to `boost::archive::basic_text_oprimitive<std::basic_ostream<char, std::char_traits<char> > >::~basic_text_oprimitive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive18text_oarchive_implINS0_13text_oarchiveEED1Ev[boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::~text_oarchive_impl()]+0x69):testoa.cpp: undefined reference to `boost::archive::basic_text_oprimitive<std::basic_ostream<char, std::char_traits<char> > >::~basic_text_oprimitive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive18text_oarchive_implINS0_13text_oarchiveEED2Ev[boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::~text_oarchive_impl()]+0x3d): In function `boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::~text_oarchive_impl()': testoa.cpp: undefined reference to `boost::archive::basic_text_oprimitive<std::basic_ostream<char, std::char_traits<char> > >::~basic_text_oprimitive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive18text_oarchive_implINS0_13text_oarchiveEED2Ev[boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::~text_oarchive_impl()]+0x69):testoa.cpp: more undefined references to `boost::archive::basic_text_oprimitive<std::basic_ostream<char, std::char_traits<char> > >::~basic_text_oprimitive()' follow /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive6detail15common_oarchiveINS0_13text_oarchiveEED1Ev[boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::~common_oarchive()]+0x18): In function `boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::~common_oarchive()': testoa.cpp: undefined reference to `boost::archive::detail::basic_oarchive::~basic_oarchive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive6detail15common_oarchiveINS0_13text_oarchiveEED0Ev[boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::~common_oarchive()]+0x18): In function `boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::~common_oarchive()': testoa.cpp: undefined reference to `boost::archive::detail::basic_oarchive::~basic_oarchive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive6detail15common_oarchiveINS0_13text_oarchiveEEC2Ev[boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::common_oarchive()]+0xe): In function `boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::common_oarchive()': testoa.cpp: undefined reference to `boost::archive::detail::basic_oarchive::basic_oarchive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive11save_access14save_primitiveINS0_13text_oarchiveESsEEvRT_RKT0_[void boost::archive::save_access::save_primitive<boost::archive::text_oarchive, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(boost::archive::text_oarchive&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)]+0x20): In function `void boost::archive::save_access::save_primitive<boost::archive::text_oarchive, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(boost::archive::text_oarchive&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)': testoa.cpp: undefined reference to `boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::save(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost13serialization25extended_type_info_typeidIK6VertexEC1Ev[boost::serialization::extended_type_info_typeid<Vertex const>::extended_type_info_typeid()]+0x28): In function `boost::serialization::extended_type_info_typeid<Vertex const>::extended_type_info_typeid()': testoa.cpp: undefined reference to `boost::serialization::extended_type_info::self_register()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive6detail21save_non_pointer_typeINS0_13text_oarchiveE6VertexE4save7invokexERS3_RKS4_[boost::archive::detail::save_non_pointer_type<boost::archive::text_oarchive, Vertex>::save::invokex(boost::archive::text_oarchive&, Vertex const&)]+0x17): In function `boost::archive::detail::save_non_pointer_type<boost::archive::text_oarchive, Vertex>::save::invokex(boost::archive::text_oarchive&, Vertex const&)': testoa.cpp: undefined reference to `boost::archive::detail::basic_oarchive::save_object(void const*, boost::archive::detail::basic_oserializer const&)' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive6detail15common_oarchiveINS0_13text_oarchiveEE4initEv[boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::init()]+0x18): In function `boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::init()': testoa.cpp: undefined reference to `boost::archive::ARCHIVE_SIGNATURE' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive6detail15common_oarchiveINS0_13text_oarchiveEE4initEv[boost::archive::detail::common_oarchive<boost::archive::text_oarchive>::init()]+0x98):testoa.cpp: undefined reference to `boost::archive::ARCHIVE_VERSION' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive18text_oarchive_implINS0_13text_oarchiveEEC2ERSoj[boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::text_oarchive_impl(std::basic_ostream<char, std::char_traits<char> >&, unsigned int)]+0x21): In function `boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::text_oarchive_impl(std::basic_ostream<char, std::char_traits<char> >&, unsigned int)': testoa.cpp: undefined reference to `boost::archive::basic_text_oprimitive<std::basic_ostream<char, std::char_traits<char> > >::basic_text_oprimitive(std::basic_ostream<char, std::char_traits<char> >&, bool)' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive18text_oarchive_implINS0_13text_oarchiveEEC2ERSoj[boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::text_oarchive_impl(std::basic_ostream<char, std::char_traits<char> >&, unsigned int)]+0x8c):testoa.cpp: undefined reference to `boost::archive::basic_text_oprimitive<std::basic_ostream<char, std::char_traits<char> > >::~basic_text_oprimitive()' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost7archive19basic_text_oarchiveINS0_13text_oarchiveEE13save_overrideERKNS0_15class_name_typeEi[boost::archive::basic_text_oarchive<boost::archive::text_oarchive>::save_override(boost::archive::class_name_type const&, int)]+0x54): In function `boost::archive::basic_text_oarchive<boost::archive::text_oarchive>::save_override(boost::archive::class_name_type const&, int)': testoa.cpp: undefined reference to `boost::archive::text_oarchive_impl<boost::archive::text_oarchive>::save(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' /tmp/ccS4C1Wt.o(.gnu.linkonce.t._ZN5boost15smart_cast_impl9referenceIRNS_7archive13text_oarchiveEE11polymorphic5cross4castINS2_6detail14basic_oarchiveEEES4_RT_[boost::archive::text_oarchive& boost::smart_cast_impl::reference<boost::archive::text_oarchive&>::polymorphic::cross::cast<boost::archive::detail::basic_oarchive>(boost::archive::detail::basic_oarchive&)]+0xe): In function `boost::archive::text_oarchive& boost::smart_cast_impl::reference<boost::archive::text_oarchive&>::polymorphic::cross::cast<boost::archive::detail::basic_oarchive>(boost::archive::detail::basic_oarchive&)': testoa.cpp: undefined reference to `typeinfo for boost::archive::detail::basic_oarchive' collect2: ld returned 1 exit status 5) Another compile and link issue was talked about on boost user-list half a year ago(http://lists.boost.org/boost-users/2005/05/11624.php) However, I could not decipher the my correct answer from that. My error looks different from the errors posted there. 6) Thanks in advance for your time and help with this issue. I think I might miss some basic points on this library. Henry .K. Wang Jan 2, 2006

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Re: [Boost-users] Boost.Serialization // Basic Usage Problem for your help!
by Merrill Cornish 03 Jan '06

03 Jan '06

Feng, I don't have the expertise to decode the full list of errors. However, I do know that there is an ordering dependency that requires all archive include files come before any serialization include files. So, try rearranging your #includes to put archive includes first and see what happens. Merrill

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Re: [Boost-users] vc 7.1 bug: multiple definitions of symbol with Boost.Test
by Ross Boylan 02 Jan '06

02 Jan '06

On Mon, 2006-01-02 at 04:48 -0500, Daryle Walker wrote: > On 12/29/05 4:21 AM, "Perepelitsa Roman" <romka(a)ptc.ru> wrote: > > > Sorry, I forgot to mention you have to enable precompiler headers to > > reproduce the problem. Project Settings -> C/C++ -> Precompiled > > Headers -> Automatically Generate. > [TRUNCATE] > > Is the header pre-compile option just for VC 7.1, or is it also for (Apple > special) GCC 3.3? As I wrote, I didn't request PCH, and I'm not even sure gcc 3.3 supports them. > Looking at the code from a few posts ago, complaining > about the GCC problem, I don't think you can use the pre-compiled header. > The auto-testing system requires BOOST_AUTO_TEST_MAIN to be #defined in > exactly one source file, which disqualifies it from being in a common > header. True, but it's not the BOOST_AUTO_TEST_MAIN that's causing the problem, or that's being included in more than one file. > Worse, that also means that other headers that pay attention to > that macro can't be in a common header, otherwise the One Definition Rule > would be broken. If you have two translation units with an anonymous namespace, they may appear to be defining the same thing twice. But the C++ standard says it is not the same thing, since each anonymous namespace is distinct. So the definitions occur in different namespaces. Compiler writers seem to be having trouble getting the correct semantics in this case. -- Ross Boylan wk: (415) 514-8146 185 Berry St #5700 ross(a)biostat.ucsf.edu Dept of Epidemiology and Biostatistics fax: (415) 514-8150 University of California, San Francisco San Francisco, CA 94107-1739 hm: (415) 550-1062

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Re: [Boost-users] multiple definitions of symbol withRe: multiple definitions of symbol with Boost.Test
by Perepelitsa Roman 02 Jan '06

02 Jan '06

>> When I try to link a test suite I get this: >> >> ld: multiple definitions of symbol boost::test_tools::(anonymous >> namespace)::check_is_close >> mspathCEntry_test.o definition of boost::test_tools::(anonymous >> namespace)::check_is_close in section (__DATA,__data) >> ModelBuilder_test.o definition of boost::test_tools::(anonymous >> namespace)::check_is_close in section (__DATA,__data) >> ld: multiple definitions of symbol boost::test_tools::(anonymous >> namespace)::check_is_small >> mspathCEntry_test.o definition of boost::test_tools::(anonymous >> namespace)::check_is_small in section (__DATA,__data) >> ModelBuilder_test.o definition of boost::test_tools::(anonymous >> namespace)::check_is_small in section (__DATA,__data) >> LinearProduct_test.o definition of boost::test_tools::(anonymous >> namespace)::check_is_close in section (__DATA,__data) >> LinearProduct_test.o definition of boost::test_tools::(anonymous >> namespace)::check_is_small in section (__DATA,__data) >> ..... >> >> This is with boost 1.33 on Darwin/OS-X. The same code was building OK >> with the 1.31 libraries (and 1.32 on linux, I think). I'm using libtool. >> Here's the makefile > I remember seeing similar report recently. As it clear from error message > linker complains about multiple definitions for symbols in anonymous > namespace. This looks like compiler bug. If you know any workarounds please > share them with us. > Gennadiy I had the same problem with vc 7.1. If you add 'static' to all variables definitions in anonymous namespaces it works fine. For example instead of namespace { check_is_close_t check_is_close; } You can write namespace { static check_is_close_t check_is_close; // note 'static' keyword } Best regards, Perepelitsa Roman.

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[serialization] assertion in basic_binary_oprimitive::save_binary() revisited
by Austin Bingham 02 Jan '06

02 Jan '06

A while ago I brought up what I considered (and still consider) to be a serious problem in basic_binary_oprimitive::save_binary(). The problem is the assert at the end of the function: assert(os.good()); There are a number of reasons why doing this is a bad idea, but the discussion on this issue was dropped flat on the floor. Is there any possibility of discussing alternatives to this assertion? At the very least, can I get an explanation of why an assert is correct to which counter-arguments might be considered? -- Austin Bingham

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boost::spirit, comment_p("//")
by elviin 02 Jan '06

02 Jan '06

Hello Boost users. I'd like to know if anyone was solving the following problem. I tried to use comment_p("//") in this way: rule_t r = *(anychar_p-comment_p("//")) % comment_p("//")[push_back_a(v)] ; This works for me except this case: C++ code: <snip> else if (szMethodName == "the test //") open(tCallParams, tAction); <snip> Problem is caused by the string "the test //". Then the source is parsed in the wrong way because //") open(tCallParams, tAction); is assumed as comment. I think I should select an allowed segment where // is valid.

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Re: [Boost-users] vc 7.1 bug: multiple definitions of symbol with Boost.Test
by Perepelitsa Roman 02 Jan '06

02 Jan '06

>> I had the same problem with vc 7.1. > Strange. I never had problems like this with vc7.1 It's very easy to reproduce the problem. Create project with two source files (e.g. a.cpp and b.cpp) both with the same content: -- begin #include <boost/test/floating_point_comparison.hpp> -- end When you try to compile you get two errors: b.obj : error LNK2005: "struct check_is_small_t::boost::check_is_small_t boost::test_tools::`anonymous namespace'::check_is_small" (?check_is_small@?A0xa003c394@test_tools@boost@@3Ucheck_is_small_t@23@A) already defined in a.obj b.obj : error LNK2005: "struct check_is_close_t::boost::check_is_close_t boost::test_tools::`anonymous namespace'::check_is_close" (?check_is_close@?A0xa003c394@test_tools@boost@@3Ucheck_is_close_t@23@A) already defined in a.obj boost version 1.33.1. >> If you add 'static' to all >> variables definitions in anonymous namespaces it works fine. > But anonimous namespace should do the trick itself! Agree. Seems like compiler bug to me. Roman.

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Building boost 1.33.1 with Comeau 4.3.3
by Pooyan McSporran 02 Jan '06

02 Jan '06

I'm having problems trying to build boost 1.33.1 with comeau 4.3.3 on Linux. Firstly, I verified that the como compiler is working by creating a 'hello world' test program, and building it with the como compiler and running it. I tried to build Boost using the information at http://www.boost.org/tools/build/v1/como-tools.html For example, $ tar -xjf boost_1_33_1.tar.bz2 $ cd boost_1_33_1 $ bjam -sTOOLS=como -sCOMO_PATH=/cc -sCOMO_INCLUDE_PATH=/cc/lib -sCOMO_STDLIB_PATH=/cc stage This results in numerous errors: Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (and if you don't know what ICU is then you probably don't need it). **** wide char i/o not supported by libcomo standard library **** **** skipping build of <@boost!libs!serialization!build>libboost_wserialization.a; toolset= como variant= debug **** **** wide char i/o not supported by libcomo standard library **** **** skipping build of <@boost!libs!serialization!build>libboost_wserialization.a; toolset= como variant= release **** **** DLLs cannot be built with this compiler **** **** skipping build of <@boost!libs!serialization!build>libboost_serialization.so; toolset= como variant= debug **** **** DLLs cannot be built with this compiler **** **** skipping build of <@boost!libs!serialization!build>libboost_serialization.so; toolset= como variant= release **** **** wide char i/o not supported by libcomo standard library **** **** DLLs cannot be built with this compiler **** **** skipping build of <@boost!libs!serialization!build>libboost_wserialization.so; toolset= como variant= debug **** **** wide char i/o not supported by libcomo standard library **** **** DLLs cannot be built with this compiler **** **** skipping build of <@boost!libs!serialization!build>libboost_wserialization.so; toolset= como variant= release **** ...patience... ...patience... ...patience... ...found 6796 targets... ...updating 789 targets... MkDir1 stage MkDir1 stage/lib MkDir1 bin MkDir1 bin/boost MkDir1 bin/boost/libs MkDir1 bin/boost/libs/regex MkDir1 bin/boost/libs/regex/build MkDir1 bin/boost/libs/regex/build/libboost_regex.so MkDir1 bin/boost/libs/regex/build/libboost_regex.so/como MkDir1 bin/boost/libs/regex/build/libboost_regex.so/como/debug como-C++-action bin/boost/libs/regex/build/libboost_regex.so/como/debug/c_regex_traits.o Comeau C/C++ 4.3.3 (Oct 24 2003 16:00:23) for RedHat_LINUX_INTEL_ELF Copyright 1988-2003 Comeau Computing. All rights reserved. MODE:strict errors C++ "/cc/lib/stl_tempbuf.h", line 53: error: identifier "INT_MAX" is undefined if (__len > ptrdiff_t(INT_MAX / sizeof(_Tp))) ^ "/cc/lib/stl_tempbuf.h", line 101: error: identifier "INT_MAX" is undefined if (_M_len > (ptrdiff_t)(INT_MAX / sizeof(_Tp))) ^ "/cc/lib/limits", line 205: error: identifier "CHAR_BIT" is undefined __STL_DECLARE_LIMITS_MEMBER(int, ^ (etc!) Am I doing something stupid? For what it's worth, I've been using boost with gcc for quite some time now with no problems, but decided to give it a try with comeau, but no luck yet. I have searched online for solutions to this, but couldn't find any solutions that work for me.

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How to identify Boost libraries which support eVC++ compiler
by Mateusz Łoskot 01 Jan '06

01 Jan '06

Hi, I'm trying to use Boost libraries with eMbedded Visual C++ 4.0 compiler (Windows CE applications development). I'd like to catalogue as much as possible Boost libraries which can be used with eVC++ 4.0 compiler. Currently, I can use smart pointers successfully. I also tried to use boost\date_time libraries and I found most of them can not be used with eVC++. I got "unknown CE compiler" error message. So, I suppose I will get that message in most cases. As I revealed there is a compiler detection mechanism in file boost\config\compiler\visualc.hpp but I couldn't find out how exactly it is used. I'd like to identify all Boost libraries which can not be used with eVC++. Could anyone give me a few hints about how to start such identification? Are there any macro definitions or can I expect that visualc.hpp can help me in this task? Thank in advance for all comments Best regards -- Mateusz Łoskot http://mateusz.loskot.net

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Problems with CVS
by Mateusz Łoskot 01 Jan '06

01 Jan '06

Hi, Yesterday I met some problems with accessing Boost CVS. I started to checkout the CVS HEAD using anonymous user. The process was going well but after a few minutes I got many timeouts errors. I tried to checkout again and update my existing sandbox but without any success. Here are errors I got when using command line CVS client: D:\__projects_mloskot\boost>cvs -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/boost login Logging in to :pserver:anonymous@cvs.sourceforge.net:2401:/cvsroot/boost CVS Password: cvs [login aborted]: Error reading from server cvs.sourceforge.net: 0: No such file or directory D:\__projects_mloskot\boost>cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/boost co -P boost cvs [checkout aborted]: Error reading from server cvs.sourceforge.net: 0: Invalid argument D:\__projects_mloskot\boost>cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/boost update -P boost cvs [update aborted]: Error reading from server cvs.sourceforge.net: 0: Invalid argument As I checked CVS Web Browser is working well, so CVS on SF.net seems to be up. Am I doing something wrong? Cheers -- Mateusz Łoskot http://mateusz.loskot.net

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Re: [Boost-users] [multi_index] const_mem_fun with an inherited member function
by JOAQUIN LOPEZ MU?Z 01 Jan '06

01 Jan '06

----- Mensaje original ----- De: Matt Steele <steelerm(a)netlab.uky.edu> Fecha: Domingo, Enero 1, 2006 8:32 pm Asunto: Re: [Boost-users] [multi_index] const_mem_fun with an inherited member function [...] > Your suggestion worked without any changes (runtime tested it > with a few toy calls to insert()/find() ). However, if instead of > invoking the global get<>() function template, I try to call the > member function template, > > return t.get<N>(); > > I get this compile error: > > error: invalid use of member (did you forget the '&' ?) > > Do you know if this code should compile? If not, is there a way > to call > a member function template in this context without relying on a global > function wrapper? Try return t.template get<N>(); Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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Re: [Boost-users] [multi_index] const_mem_fun with an inherited member function
by Matt Steele 01 Jan '06

01 Jan '06

Hello Joaquin, Thank you for your response. > 2. I think that the code won't work as expected: const_mem_fun > has some overloads of operator() in order to support > chained pointers (http://tinyurl.com/9cd2v) that will hide > the implicit conversion from const tuple<int>& to > const tuple<int>::inherited&. Could you please try to insert > some element in my_tuple_container_type? My hunch is that > you'll get a compiler error about tuple<int> not having > operator*. Please report back. You're right; the code fails to compile and for the reason you give. > remains. My suggestion is that you simply provide a user-defined > key extractor like this (uncompiled, beware typos): > template<typename Tuple,int N> > struct tuple_member_extractor > { > typedef typename > boost::tuples::element<N,Tuple>::type result_type; > > const result_type& operator()(const Tuple& t)const > { > return boost::tuples::get<N>(t); > } > }; > > Hope this helps; I'd appreciate if you reported on the > success/failure of this approach. > Your suggestion worked without any changes (runtime tested it with a few toy calls to insert()/find() ). However, if instead of invoking the global get<>() function template, I try to call the member function template, return t.get<N>(); I get this compile error: error: invalid use of member (did you forget the '&' ?) Do you know if this code should compile? If not, is there a way to call a member function template in this context without relying on a global function wrapper? Thanks, Matt

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Re: [Boost-users] Why is boost::thread::mutex noncopyable?
by Phil Endecott 01 Jan '06

01 Jan '06

>>Can someone help me to understand why boost::thread::mutex is >>noncopyable? I expect that there is a good reason, but I can't see it >>at the moment. > > http://www.boost.org/doc/html/threads/faq.html#id2786688 Thanks for the link. Here is the text: Why do Mutexes have noncopyable semantics? To ensure that deadlocks don't occur. The only logical form of copy would be to use some sort of shallow copy semantics in which multiple mutex objects could refer to the same mutex state. This means that if ObjA has a mutex object as part of its state and ObjB is copy constructed from it, then when ObjB::foo() locks the mutex it has effectively locked ObjA as well. This behavior can result in deadlock. Other copy semantics result in similar problems (if you think you can prove this to be wrong then supply us with an alternative and we'll reconsider). I disagree with the first comment: "The only logical form of copy would be to use some sort of shallow copy semantics in which multiple mutex objects could refer to the same mutex state." What's wrong with the copy of a mutex being a new independent mutex? (There's a problem if you copy a locked mutex, but I don't propose to do that.) --Phil.

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Re: [Boost-users] Why is boost::thread::mutex noncopyable?
by Phil Endecott 01 Jan '06

01 Jan '06

>>Can someone help me to understand why boost::thread::mutex is >>noncopyable? I expect that there is a good reason, but I can't see it >>at the moment. > > http://www.boost.org/doc/html/threads/faq.html#id2786688 I'm being a bit dense - a subsequent FAQ shows how you can write a copy-constructor for a struct that contains a mutex that explicitly copies the data, giving you a new default-constructed mutex. The constructor can even lock the thing it is copying. --Phil.

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