May 2007 - Boost-users - lists.preview.boost.org

[Boost.Signals] bug
by Yashin Evgeny 28 May '07

28 May '07

Here is, minimal example. struct Conn : public boost::signals::trackable { void operator()(){} }; void f() { boost::signal<void ()> sig; Conn c; sig.connect( c ); c = Conn(); // crash inside.. } The reason is simple. During clear() method of std::list, there are signals::connection destructor calls are happening, which, in turn, calling erase method of the same std::list, and as a result we're getting _DEBUG_ERROR("list erase iterator outside range"); I guess, the bug is with "dying" variable: in destructor, it was set to true, and then signals::connection destructors are not trying to remove themself from the std::list. But in boost::signals::trackable::operator=() there is no dying flag marking. Evgeny.

1 0

[ptr_vector] vector<ptr_vector < T > >
by Seweryn Habdank-Wojewódzki 28 May '07

28 May '07

Hi! Can anyone tell me why std::vector < boost::ptr_vector < T > > can not be reserved and resized I can not push_back anything inside vector, due to compile errors? I am using ptr_vector for storing copyable, but nonassignable objects of type T - in fact objects contains mainly const elements. Regards. #include <iostream> #include <vector> #include <boost/ptr_container/ptr_vector.hpp> class Foo { public: Foo ( int const i, int const & j ) :i_(i), j_(j) {} Foo ( Foo const & f ) : i_(f.i_), j_(f.j_) {} private: int const i_; int const & j_; void operator= ( Foo const & f ); }; int main() { using namespace std; using namespace boost; int k = 10; ptr_vector<Foo> g; g.push_back ( new Foo(1,k) ); vector<ptr_vector<Foo> > d; //d.push_back ( g ); <-- Errors //d.resize(5) //d.reserve(5) } -- |\/\/| Seweryn Habdank-Wojewódzki \/\/

6 9

Boost 1.34.0 Builds *Almost* Perfectly - 4 Failures with BJam [Regex/ICU-related]
by Lawrence Spector 28 May '07

28 May '07

Any ideas? I think they're related to ICU. I downloaded ICU 3.6 (the latest). However, I am using this with VS2005, which was "rarely tested" according to the website. Still, after converting the ICU project to VS2005 and building, I had no build errors, but I do get these link errors with boost, which all seem to be ICU-related. See below: -------------- D:\3rdparty\boost_1_34_0>call "C:\Program Files\Microsoft Visual Studio 8\VC\vcvarsall.bat" x86 Setting environment for using Microsoft Visual Studio 2005 x86 tools. Building Boost.Regex with Unicode/ICU support enabled Using ICU in D:\3rdparty\icu4c-3_6/include ...patience... ...patience... ...found 5406 targets... ...updating 10 targets... msvc.link.dll bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80- mt-gd-1_34.dll bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80- mt-gd-1_34.lib Creating library bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80- mt-gd-1_34.lib and object bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80- mt-gd-1_34.exp icu.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __thiscall icu_3_6::Locale::~Locale(void)" (__imp_??1Locale@icu_3_6@@UAE@XZ) referenced in function __unwindfunclet$??0icu_regex_traits_implementation@re_detail@boost@@QAE@ ABVLocale@icu_3_6@@@Z$0 icu.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: static class icu_3_6::Collator * __cdecl icu_3_6::Collator::createInstance(class icu_3_6::Locale const &,enum UErrorCode &)" (__imp_?createInstance@Collator@icu_3_6@@SAPAV12@ABVLocale@2@AAW4UErrorC ode@@@Z) referenced in function "public: __thiscall boost::re_detail::icu_regex_traits_implementation::icu_regex_traits_impl ementation(class icu_3_6::Locale const &)" (??0icu_regex_traits_implementation@re_detail@boost@@QAE@ABVLocale@icu_3 _6@@@Z) icu.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall icu_3_6::Locale::Locale(class icu_3_6::Locale const &)" (__imp_??0Locale@icu_3_6@@QAE@ABV01@@Z) referenced in function "public: __thiscall boost::re_detail::icu_regex_traits_implementation::icu_regex_traits_impl ementation(class icu_3_6::Locale const &)" (??0icu_regex_traits_implementation@re_detail@boost@@QAE@ABVLocale@icu_3 _6@@@Z) icu.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall icu_3_6::Locale::Locale(void)" (__imp_??0Locale@icu_3_6@@QAE@XZ) referenced in function "public: __thiscall boost::icu_regex_traits::icu_regex_traits(void)" (??0icu_regex_traits@boost@@QAE@XZ) icu.obj : error LNK2019: unresolved external symbol _u_tolower_3_6 referenced in function "public: unsigned __int64 __thiscall boost::icu_regex_traits::lookup_classname(int const *,int const *)const " (?lookup_classname@icu_regex_traits@boost@@QBE_KPBH0@Z) icu.obj : error LNK2019: unresolved external symbol _u_toupper_3_6 referenced in function "public: int __thiscall boost::icu_regex_traits::toupper(int)const " (?toupper@icu_regex_traits@boost@@QBEHH@Z) icu.obj : error LNK2019: unresolved external symbol _u_digit_3_6 referenced in function "public: bool __thiscall boost::icu_regex_traits::isctype(int,unsigned __int64)const " (?isctype@icu_regex_traits@boost@@QBE_NH_K@Z) icu.obj : error LNK2019: unresolved external symbol _u_isspace_3_6 referenced in function "public: unsigned __int64 __thiscall boost::icu_regex_traits::lookup_classname(int const *,int const *)const " (?lookup_classname@icu_regex_traits@boost@@QBE_KPBH0@Z) icu.obj : error LNK2019: unresolved external symbol _u_charFromName_3_6 referenced in function "public: class std::vector<int,class std::allocator<int> > __thiscall boost::icu_regex_traits::lookup_collatename(int const *,int const *)const " (?lookup_collatename@icu_regex_traits@boost@@QBE?AV?$vector@HV?$allocato r@H@std@@@std@@PBH0@Z) icu.obj : error LNK2019: unresolved external symbol _u_isblank_3_6 referenced in function "public: bool __thiscall boost::icu_regex_traits::isctype(int,unsigned __int64)const " (?isctype@icu_regex_traits@boost@@QBE_NH_K@Z) icu.obj : error LNK2019: unresolved external symbol _u_charType_3_6 referenced in function "public: bool __thiscall boost::icu_regex_traits::isctype(int,unsigned __int64)const " (?isctype@icu_regex_traits@boost@@QBE_NH_K@Z) bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80- mt-gd-1_34.dll : fatal error LNK1120: 11 unresolved externals call "C:\Program Files\Microsoft Visual Studio 8\VC\vcvarsall.bat" x86 >nul link /NOLOGO /INCREMENTAL:NO /DLL /DEBUG /subsystem:console /out:"bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex -vc80-mt-gd-1_34.dll" /IMPLIB:"bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_re gex-vc80-mt-gd-1_34.lib" @"bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc8 0-mt-gd-1_34.dll.rsp" if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL% if exist "bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80 -mt-gd-1_34.dll.manifest" ( mt -nologo -manifest "bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80 -mt-gd-1_34.dll.manifest" "-outputresource:bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\ boost_regex-vc80-mt-gd-1_34.dll;2" ) ...failed msvc.link.dll bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80- mt-gd-1_34.dll bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80- mt-gd-1_34.lib... ...removing bin.v2\libs\regex\build\msvc-8.0\debug\threading-multi\boost_regex-vc80- mt-gd-1_34.lib ...skipped <pstage\lib>boost_regex-vc80-mt-gd-1_34.dll for lack of <pbin.v2\libs\regex\build\msvc-8.0\debug\threading-multi>boost_regex-vc8 0-mt-gd-1_34.dll... ...skipped <pstage\lib>boost_regex-vc80-mt-gd-1_34.lib for lack of <pbin.v2\libs\regex\build\msvc-8.0\debug\threading-multi>boost_regex-vc8 0-mt-gd-1_34.lib... ...skipped <pstage\lib>boost_regex-vc80-mt-gd.lib for lack of <pstage\lib>boost_regex-vc80-mt-gd-1_34.lib... msvc.link.dll bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc8 0-mt-1_34.dll bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc8 0-mt-1_34.lib Creating library bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc8 0-mt-1_34.lib and object bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc8 0-mt-1_34.exp icu.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall icu_3_6::Locale::Locale(class icu_3_6::Locale const &)" (__imp_??0Locale@icu_3_6@@QAE@ABV01@@Z) referenced in function "public: class icu_3_6::Locale __thiscall boost::re_detail::icu_regex_traits_implementation::getloc(void)const " (?getloc@icu_regex_traits_implementation@re_detail@boost@@QBE?AVLocale@i cu_3_6@@XZ) icu.obj : error LNK2019: unresolved external symbol _u_tolower_3_6 referenced in function "public: int __thiscall boost::icu_regex_traits::translate_nocase(int)const " (?translate_nocase@icu_regex_traits@boost@@QBEHH@Z) icu.obj : error LNK2019: unresolved external symbol _u_toupper_3_6 referenced in function "public: int __thiscall boost::icu_regex_traits::toupper(int)const " (?toupper@icu_regex_traits@boost@@QBEHH@Z) icu.obj : error LNK2019: unresolved external symbol _u_digit_3_6 referenced in function "public: int __thiscall boost::icu_regex_traits::value(int,int)const " (?value@icu_regex_traits@boost@@QBEHHH@Z) icu.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __thiscall icu_3_6::Locale::Locale(void)" (__imp_??0Locale@icu_3_6@@QAE@XZ) referenced in function "public: class icu_3_6::Locale __thiscall boost::icu_regex_traits::getloc(void)const " (?getloc@icu_regex_traits@boost@@QBE?AVLocale@icu_3_6@@XZ) icu.obj : error LNK2019: unresolved external symbol _u_isspace_3_6 referenced in function "public: bool __thiscall boost::icu_regex_traits::isctype(int,unsigned __int64)const " (?isctype@icu_regex_traits@boost@@QBE_NH_K@Z) icu.obj : error LNK2019: unresolved external symbol _u_isblank_3_6 referenced in function "public: bool __thiscall boost::icu_regex_traits::isctype(int,unsigned __int64)const " (?isctype@icu_regex_traits@boost@@QBE_NH_K@Z) icu.obj : error LNK2019: unresolved external symbol _u_charType_3_6 referenced in function "public: bool __thiscall boost::icu_regex_traits::isctype(int,unsigned __int64)const " (?isctype@icu_regex_traits@boost@@QBE_NH_K@Z) icu.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __thiscall icu_3_6::Locale::~Locale(void)" (__imp_??1Locale@icu_3_6@@UAE@XZ) referenced in function __unwindfunclet$??0icu_regex_traits_implementation@re_detail@boost@@QAE@ ABVLocale@icu_3_6@@@Z$0 icu.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: static class icu_3_6::Collator * __cdecl icu_3_6::Collator::createInstance(class icu_3_6::Locale const &,enum UErrorCode &)" (__imp_?createInstance@Collator@icu_3_6@@SAPAV12@ABVLocale@2@AAW4UErrorC ode@@@Z) referenced in function "public: __thiscall boost::re_detail::icu_regex_traits_implementation::icu_regex_traits_impl ementation(class icu_3_6::Locale const &)" (??0icu_regex_traits_implementation@re_detail@boost@@QAE@ABVLocale@icu_3 _6@@@Z) icu.obj : error LNK2019: unresolved external symbol _u_charFromName_3_6 referenced in function "public: class std::vector<int,class std::allocator<int> > __thiscall boost::icu_regex_traits::lookup_collatename(int const *,int const *)const " (?lookup_collatename@icu_regex_traits@boost@@QBE?AV?$vector@HV?$allocato r@H@std@@@std@@PBH0@Z) bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc8 0-mt-1_34.dll : fatal error LNK1120: 11 unresolved externals call "C:\Program Files\Microsoft Visual Studio 8\VC\vcvarsall.bat" x86 >nul link /NOLOGO /INCREMENTAL:NO /DLL /subsystem:console /out:"bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_reg ex-vc80-mt-1_34.dll" /IMPLIB:"bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_ regex-vc80-mt-1_34.lib" @"bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-v c80-mt-1_34.dll.rsp" if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL% if exist "bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc 80-mt-1_34.dll.manifest" ( mt -nologo -manifest "bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc 80-mt-1_34.dll.manifest" "-outputresource:bin.v2\libs\regex\build\msvc-8.0\release\threading-mult i\boost_regex-vc80-mt-1_34.dll;2" ) ...failed msvc.link.dll bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc8 0-mt-1_34.dll bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc8 0-mt-1_34.lib... ...removing bin.v2\libs\regex\build\msvc-8.0\release\threading-multi\boost_regex-vc8 0-mt-1_34.lib ...skipped <pstage\lib>boost_regex-vc80-mt-1_34.dll for lack of <pbin.v2\libs\regex\build\msvc-8.0\release\threading-multi>boost_regex-v c80-mt-1_34.dll... ...skipped <pstage\lib>boost_regex-vc80-mt-1_34.lib for lack of <pbin.v2\libs\regex\build\msvc-8.0\release\threading-multi>boost_regex-v c80-mt-1_34.lib... ...skipped <pstage\lib>boost_regex-vc80-mt.lib for lack of <pstage\lib>boost_regex-vc80-mt-1_34.lib... ...failed updating 4 targets... ...skipped 6 targets... -------------------- Thanks in advance for any help that can be provided, Lawrence

3 7

[1.34.0] building on cygwin fails out of the box
by Andy Stevenson 28 May '07

28 May '07

All, Trying to build 1.34.0 out of the box on Cygwin yields the following errors when trying to install it. Ideas? ./tools/jam/src/bin.cygwinx86/bjam --user-config=user-config.jam --prefix=/usr/local --exec-prefix=/usr/local --libdir=/usr/local/lib --includedir=/usr/local/include install Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (don't panic: this is a strictly optional feature). /boost/boost_1_34_0/tools/build/v2/build/virtual-target.jam:996: in virtual-target.register-actual-name from module virtual-target error: Duplicate name of actual target: <p/usr/local/lib>exact.dll.a error: previous virtual target { common%common.hard-link-exact.dll.a.IMPORT_LIB { common%common.copy-boost_signals-gcc41-mt-d-1_34.dll.a.IMPORT_LIB { gcc%gcc.link.dll-boost_signals-gcc41-mt-d-1_34.dll.a.IMPORT_LIB { gcc%gcc.compile.c++-trackable.o.OBJ { trackable.cpp.CPP } } { gcc%gcc.compile.c++-connection.o.OBJ { connection.cpp.CPP } } { gcc%gcc.compile.c++-named_slot_map.o.OBJ { named_slot_map.cpp.CPP } } { gcc%gcc.compile.c++-signal_base.o.OBJ { signal_base.cpp.CPP } } { gcc%gcc.compile.c++-slot.o.OBJ { slot.cpp.CPP } } } } } error: created from ./install-unversioned error: another virtual target { common%common.hard-link-exact.dll.a.IMPORT_LIB { common%common.copy-boost_prg_exec_monitor-gcc41-mt-d-1_34.dll.a.IMPORT_LIB { gcc%gcc.link.dll-boost_prg_exec_monitor-gcc41-mt-d-1_34.dll.a.IMPORT_LIB { gcc%gcc.compile.c++-execution_monitor.o.OBJ { execution_monitor.cpp.CPP } } { gcc%gcc.compile.c++-cpp_main.o.OBJ { cpp_main.cpp.CPP } } } } } error: created from ./install-unversioned error: added properties: <define>BOOST_TEST_DYN_LINK=1 error: removed properties: <define>BOOST_SIGNALS_DYN_LINK=1 <define>BOOST_SIGNALS_NO_LIB=1 /boost/boost_1_34_0/tools/build/v2/build/virtual-target.jam:459: in actualize-no-scanner from module object(file-target)@16510 /boost/boost_1_34_0/tools/build/v2/build/virtual-target.jam:111: in object(file-target)(a)16510.actualize from module object(file-target)@16510 /boost/boost_1_34_0/tools/build/v2/build-system.jam:476: in load from module build-system /boost/boost_1_34_0/tools/build/v2/kernel/modules.jam:261: in import from module modules /boost/boost_1_34_0/tools/build/v2/kernel/bootstrap.jam:132: in boost-build from module /boost/boost_1_34_0/boost-build.jam:9: in module scope from module Not all Boost libraries built properly. Andy Stevenson

7 12

[Boost.Program_Options] Assertion failed on a Windows Form Application
by JD 28 May '07

28 May '07

Hi, When I create a "Windows Forms Application" under Visual C++ Express and add these lines to the main .cpp file: #include <boost/program_options.hpp> static boost::program_options::variables_map vm; and then set the the project property 'Common Language Runtime support' to /clr (/clr:pure make compilation fails), I got an assertion failure on dbgheap.c line 1414, expression: _CrtIsValidHeapPointer(pUserData) on the line: BOOST_PROGRAM_OPTIONS_DECL std::string arg("arg"); in value_semantic.cpp. Compiler command line: /Od /I "G:\Program Files\boost-cvs\boost" /D "WIN32" /D "_DEBUG" /D "_UNICODE" /D "UNICODE" /FD /EHa /MDd /Yu"stdafx.h" /Fp"Debug\po_assert.pch" /Fo"Debug\\" /Fd"Debug\vc80.pdb" /W3 /nologo /c /Zi /clr /TP /errorReport:prompt /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.dll" /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Data.dll" /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Drawing.dll" /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Windows.Forms.dll" /FU "c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.XML.dll" Linker command line: /OUT:"G:\Projects\po_assert\Debug\po_assert.exe" /INCREMENTAL /NOLOGO /LIBPATH:"G:\Program Files\boost-cvs\boost\stage\lib" /MANIFEST /MANIFESTFILE:"Debug\po_assert.exe.intermediate.manifest" /DEBUG /ASSEMBLYDEBUG /PDB:"g:\projects\po_assert\debug\po_assert.pdb" /SUBSYSTEM:WINDOWS /ENTRY:"main" /MACHINE:X86 /FIXED:No /ERRORREPORT:PROMPT Using a pointer and dynamically allocation a variables_map ends the same way... What am I doing wrong ? Or is it a known problem ? Thank you. JD

2 1

Re: [Boost-users] [iostreams] Issue with closing of filters [PATCH]
by Chad Walters 28 May '07

28 May '07

gchen <chengang31(a)gmail.com> wrote: > It seems like a issue with close_impl<closable_tag>::close(...). > ... > (link: http://www.boost.org/libs/iostreams/doc/functions/close.html) Yes, that looks like the right answer. The code is clearly not performing what the document describes. When I fix this up, my code works as expected. Proposed patch attached. >> I think the wfilter versions of these typedefs should use >> multichar_wfilter<...>. Agreed? > > A copy-n-paste bug !? Yep, that's my take -- proposed patch attached. > My $0.02 Worth much more than that... many thanks! Chad Walters

2 1

auto-link problem
by Rob Agar 27 May '07

27 May '07

hi all, Apologies if this question has been asked a million times before, but having searched the archives and documentation I'm none the wiser. Basically the problem is this: the auto-linker is trying to link to the wrong boost::filesystem lib and I can't figure out out to fix it. The error from MS Visual Studio 2005 is "LINK : fatal error LNK1104: cannot open file 'libboost_filesystem-vc80-mt-gd-1_34.lib'". Fair enough because this file does not exist. I want it to use the dll import lib boost_filesystem-vc80-mt-gd-1_34.lib. This file does exist, and is in a directory on the MSVC lib search path, along with the matching dll. So the question is, how do I tell the auto-linker to link to the file I want, or if this is not possible, how do I switch off auto-linking? I would rather not recompile the boost libs if I can help it. Thanks Rob

3 4

[date time] are months and years derived from date_duration?
by Seweryn Habdank-Wojewódzki 27 May '07

27 May '07

Hi I have simple problem if months and years derived from date_duration? The goal is that user can dynamically choose a time of events that appear periodically in shedule e.g. every 20th of any month is a meeting or every 3 months something other happens or birthsday is one per year. Regards. -- |\/\/| Seweryn Habdank-Wojewódzki \/\/

2 5

[iostreams] Issue with closing of filters (esp. tee_filter)
by Chad Walters 27 May '07

27 May '07

I am running into an issue with iostreams related to the closing of filters (tee_filter in particular) and I think I really need a little help. Thanks in advance to anyone patient enough to read through the following. I created a multichar_output_filter called ChecksumFilter. It outputs a crc for every 4K of data streamed into it. I am using in conjunction with a tee_filter to stream out a file of checksums in parallel with another file stream. Unfortunately, ChecksumFilter::close() is not invoked at times when I believe it should be, resulting in the checksum for the final chunk of data not getting pushed out. The following code shows the problem: typedef boost::iostreams::composite<ChecksumFilter, boost::iostreams::file_sink> ChecksumComposite; char buffer1[BufferSize]; memset(buffer1, DefaultValue, sizeof(buffer1)); std::string fileName1(tmpnam(0)); std::string fileName2(tmpnam(0)); boost::iostreams::file_sink sink1(fileName1.c_str()); boost::iostreams::file_sink sink2(fileName2.c_str()); ChecksumFilter chksum; ChecksumComposite comp(chksum, sink2); boost::iostreams::tee_filter<ChecksumComposite> tee(comp); { boost::iostreams::filtering_stream<boost::iostreams::output> ostream; ostream.push(tee); ostream.push(sink1); result = boost::iostreams::write(ostream, buffer1, sizeof(buffer1)); } // ChecksumFilter::close() is not invoked here!!! ChecksumFilter itself is pretty basic -- it is simply a multichar_output_filter: class ChecksumFilter : public boost::iostreams::multichar_output_filter { public: ChecksumFilter(void) : mImpl(new details::ChecksumFilterImpl()) { // Nothing to do here } template<typename Sink> std::streamsize write(Sink& sink, const char* s, std::streamsize n) { return mImpl->write<Sink>(sink, s, n); } template<typename Sink> void close(Sink& sink) { mImpl->close<Sink>(sink); } private: boost::shared_ptr<details::ChecksumFilterImpl> mImpl; }; I don't think the details of ChecksumFilterImpl are relevant. I spent some time tracing through the closing code path. I'm sure this comes as no surprise to anyone but it's quite a twisty maze. I will be the first to admit that my understanding of the library is incomplete, but here is something that I think is a bit odd -- somewhere along the way between the code in closer.hpp and tee.hpp, the openmode gets converted from BOOST_IOS::out to BOOST_IOS::in | BOOST_IOS::out. >From closer.hpp: template<> struct close_impl<closable_tag> { template<typename T> static void close(T& t, BOOST_IOS::openmode which) { printf("close closable_tag 1\n"); typedef typename category_of<T>::type category; const bool in = is_convertible<category, input>::value && !is_convertible<category, output>::value; if (in == ((which & BOOST_IOS::in) != 0)) { t.close(); } } template<typename T, typename Sink> static void close(T& t, Sink& snk, BOOST_IOS::openmode which) { typedef typename category_of<T>::type category; const bool in = is_convertible<category, input>::value && !is_convertible<category, output>::value; if (in == ((which & BOOST_IOS::in) != 0)) { non_blocking_adapter<Sink> nb(snk); t.close(nb); } } }; >From tee.hpp: template<typename Device> class tee_filter : public detail::basic_adapter<Device> { public: ... template<typename Next> void close( Next&, BOOST_IOS::openmode which = BOOST_IOS::in | BOOST_IOS::out ) { iostreams::close(this->component(), which); } ... }; The original openmode at the start of the close chain is BOOST_IOS::out, but the close_impl's two close methods discard that openmode when they call t.close() or t.close(nb). This means that tee_filter's close() sets openmode to its default value of BOOST_IOS::in | BOOST_IOS::out. This mode is passed along to iostreams::close(), which ends up back in close_impl close() again as it is attempting to close the ChecksumFilter. However, now the check "if (in == ((which & BOOST_IOS::in) != 0))" fails, and so ChecksumFilter.close() is never invoked. If I change the default value for openmode in tee_filter::close() to BOOST_IOS::out, everything works OK for me, but I am not really sure that this is the right thing to do. It appears that some kind of custom closing in closer.hpp could be done for tee_filters that would pass through the openmode, much like the handling for classes that support the two_sequence tag (sorry if I am jumbling terminology a bit here). But I am not sure my understanding of the overall code is strong enough to do the right thing here either. Can anyone help me out or put me in touch with someone who can? Much thanks! Chad Walters PS: And if you read this far, you probably understand the iostreams library more than well enough to confirm whether the possible (likely?) bug I reported earlier this week is really a bug (nobody has replied as of yet): At the bottom of concepts.hpp, the following typedefs appear: typedef multichar_filter<input> multichar_input_filter; typedef multichar_filter<input> multichar_input_wfilter; typedef multichar_filter<output> multichar_output_filter; typedef multichar_filter<output> multichar_output_wfilter; typedef multichar_filter<dual_use> multichar_dual_use_filter; typedef multichar_filter<dual_use> multichar_dual_use_wfilter; I think the wfilter versions of these typedefs should use multichar_wfilter<...>. Agreed?

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Re: [Boost-users] Boost-users Digest, Vol 1279, Issue 2
by Yaoltzin Gomez 26 May '07

26 May '07

Thank you for you time to answer. Allthough your answer has helped me, I still have the bad_weak_ptr exception. Every time I try to access the shared_from_this pointer from inside Base member functions, I get that exception. What I want to know is how can I access safely an without errors, the shared_from_this pointer inside my Base class, when I create a smart pointer instance of my Derived class. In derived I don't have that problem (I can access shared_from_this) because this is the class the instance is created. Thanks in advance Peter Dimov wrote: > Yaoltzin Gomez wrote: > > > Basically, what I have is this: > > > > class Base : public boost::enable_shared_from_this<Base> > > { > > boost::shared_ptr<Base> GetBasePointer() > > { > > return shared_from_this(); > > } > > > > void Foo() > > { > > shared_ptr<Child> child( new Child ); > > AddChild( child, GetBasePointer() ); > > } > > }; > > > > class Derived: public Base, public > > boost::enable_shared_from_this<Derived> { > > boost::shared_ptr<Derived> GetDerivedPointer() > > { > > return shared_from_this(); > > } > > [...] > > One way to avoid putting more than one enable_shared_from_this<> base into > Derived is to use > > class Derived: public Base > { > boost::shared_ptr<Derived> GetDerivedPointer() > { > return dynamic_pointer_cast<Derived>( shared_from_this() ); > } > > // ... > }; > > static_pointer_cast will also work in this case (it will fail if Derived > uses virtual inheritance). >

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