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boost exception question when threading library header is included.
by Robert Ramey 10 Jun '11

10 Jun '11

I am building a small ap to test the ASIO library. I run my test ap and things run as expected. But when I set my IDE options (MSVC 8.0) to trap when an exception is thrown, I get an exception thrown before main(.. is invoked. The call stack looks like: msvcr90d.dll!_CxxThrowException(void * pExceptionObject=0x0012fc3c, const _s__ThrowInfo * pThrowInfo=0x0047f944) Line 161 C++ time_pair.exe!boost::copy_exception<boost::exception_detail::bad_alloc_>(const boost::exception_detail::bad_alloc_ & e={...}) Line 47 C++ time_pair.exe!boost::exception_detail::get_bad_alloc<42>() Line 80 + 0x9f bytes C++ time_pair.exe!`dynamic initializer for 'boost::exception_detail::exception_ptr_bad_alloc<42>::e''() Line 94 + 0x28 bytes C++ msvcr90d.dll!_initterm(void (void)* * pfbegin=0x004743c4, void (void)* * pfend=0x00474758) Line 903 C time_pair.exe!__tmainCRTStartup() Line 497 + 0xf bytes C time_pair.exe!mainCRTStartup() Line 399 C this seems to point an attempt to copy something non_copyable in the boost.exception library. Can anyone help me understand what's going on here and what I should do about it? Here is a small test which you can use to demonstrate the problem #include <boost/thread.hpp> int main(int argc, char * argv[]){ return 0; } Robert Ramey

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Potential access violation in Boost.Regex
by Сергей Филиппов 10 Jun '11

10 Jun '11

Hi all, recently, I've found a bug in regex that can lead to access violation. std::string s(".*?"); boost::regex regEx(s.begin(), s.end()); // Potential AV here basic_regex constructor creates a local variable of type traits::string_type and passes its the first element address and one-beyond-the-last element address to the assing() function. template <class InputIterator> basic_regex(InputIterator arg_first, InputIterator arg_last, flag_type f = regex_constants::normal) { typedef typename traits::string_type seq_type; seq_type a(arg_first, arg_last); if(a.size()) assign(&*a.begin(), &*a.begin() + a.size(), f); else assign(static_cast<const charT*>(0), static_cast<const charT*>(0), f); } Calling assign() eventually leads to creation of basic_regex_parser object and calling its parse_repeat() function. m_begin and m_end members are initialized with values passed to assign(). template <class charT, class traits> bool basic_regex_parser<charT, traits>::parse_repeat(std::size_t low, std::size_t high) { ... // OK we have a perl or emacs regex, check for a '?': if(this->m_traits.syntax_type(*m_position) == regex_constants::syntax_question) { greedy = false; ++m_position; } // for perl regexes only check for pocessive ++ repeats. if((0 == (this->flags() & regbase::main_option_type)) && (this->m_traits.syntax_type(*m_position) == regex_constants::syntax_plus)) { pocessive = true; ++m_position; } ... } In parse_repeat() the m_position, member points to '?' so condition in the first if is true and m_position is advanced by ++m_position. Now it is equal to m_end. In the next if statement, *m_position is evaluated that may cause access violation. Actually, it is unlikely that the sample code above will cause AV. It is because seq_type in basic_regex constructor is basic_string, and basic_string's underlying buffer is usually null-terminated. So m_end points to the null terminator. It always readable, no AV can happen. The actual code I used is slightly different but the concept is the same: boost::u32regex regEx = boost::make_u32regex(L".*?"); u32regex and make_u32regex are provided by the ICU library. That is a way to support unicode strings. seq_type become std::vector<int,std::allocator<int> >. Some time the "a" object's underlying buffer was allocated right in the end of page, so basic_regex_parser::m_end pointed to the start of the next page that was not allocated. Dereferencing m_position caused access violation. My environment is Visual VC++ 9.0, Boost 1.42.0 (as far I can see, the code in Boost 1.46.1 is the same). By the way. When traits::string_type is basic_string, the code in basic_regex::basic_regex is not portable: assign(&*a.begin(), &*a.begin() + a.size(), f); If I remember correctly, standard does not guarantee that basic_string's controlling sequence is contiguous. Just in case, the call stack when AV occured: boost::re_detail::basic_regex_parser<int,boost::icu_regex_traits>::parse_repeat+0x87 boost::re_detail::basic_regex_parser<int,boost::icu_regex_traits>::parse_extended+0x182 boost::re_detail::basic_regex_parser<int,boost::icu_regex_traits>::parse+0x133 boost::re_detail::basic_regex_implementation<int,boost::icu_regex_traits>::assign+0x98 boost::basic_regex<int,boost::icu_regex_traits>::do_assign+0x14c boost::basic_regex<int,boost::icu_regex_traits>::assign+0x16 boost::basic_regex<int,boost::icu_regex_traits>::assign<int *>+0xa2 boost::basic_regex<int,boost::icu_regex_traits>::basic_regex<int,boost::icu_regex_traits><boost::u16_to_u32_iterator<wchar_t const *,int> >+0xb8 boost::re_detail::do_make_u32regex<wchar_t const *>+0x25 boost::make_u32regex+0x2c Sergey

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(no subject)
by Сергей Филиппов 10 Jun '11

10 Jun '11

Hi all, recently, I've found a bug in regex that can lead to access violation. std::string s(".*?"); boost::regex regEx(s.begin(), s.end()); // Potential AV here basic_regex constructor creates a local variable of type traits::string_type and passes its the first element address and one-beyond-the-last element address to the assing() function. template <class InputIterator> basic_regex(InputIterator arg_first, InputIterator arg_last, flag_type f = regex_constants::normal) { typedef typename traits::string_type seq_type; seq_type a(arg_first, arg_last); if(a.size()) assign(&*a.begin(), &*a.begin() + a.size(), f); else assign(static_cast<const charT*>(0), static_cast<const charT*>(0), f); } Calling assign() eventually leads to creation of basic_regex_parser object and calling its parse_repeat() function. m_begin and m_end members are initialized with values passed to assign(). template <class charT, class traits> bool basic_regex_parser<charT, traits>::parse_repeat(std::size_t low, std::size_t high) { ... // OK we have a perl or emacs regex, check for a '?': if(this->m_traits.syntax_type(*m_position) == regex_constants::syntax_question) { greedy = false; ++m_position; } // for perl regexes only check for pocessive ++ repeats. if((0 == (this->flags() & regbase::main_option_type)) && (this->m_traits.syntax_type(*m_position) == regex_constants::syntax_plus)) { pocessive = true; ++m_position; } ... } In parse_repeat() the m_position, member points to '?' so condition in the first if is true and m_position is advanced by ++m_position. Now it is equal to m_end. In the next if statement, *m_position is evaluated that may cause access violation. Actually, it is unlikely that the sample code above will cause AV. It is because seq_type in basic_regex constructor is basic_string, and basic_string's underlying buffer is usually null-terminated. So m_end points to the null terminator. It always readable, no AV can happen. The actual code I used is slightly different but the concept is the same: boost::u32regex regEx = boost::make_u32regex(L".*?"); u32regex and make_u32regex are provided by the ICU library. That is a way to support unicode strings. seq_type become std::vector<int,std::allocator<int> >. Some time the "a" object's underlying buffer was allocated right in the end of page, so basic_regex_parser::m_end pointed to the start of the next page that was not allocated. Dereferencing m_position caused access violation. My environment is Visual VC++ 9.0, Boost 1.42.0 (as far I can see, the code in Boost 1.46.1 is the same). By the way. When traits::string_type is basic_string, the code in basic_regex::basic_regex is not portable: assign(&*a.begin(), &*a.begin() + a.size(), f); If I remember correctly, standard does not guarantee that basic_string's controlling sequence is contiguous. Just in case, the call stack when AV occured: boost::re_detail::basic_regex_parser<int,boost::icu_regex_traits>::parse_repeat+0x87 boost::re_detail::basic_regex_parser<int,boost::icu_regex_traits>::parse_extended+0x182 boost::re_detail::basic_regex_parser<int,boost::icu_regex_traits>::parse+0x133 boost::re_detail::basic_regex_implementation<int,boost::icu_regex_traits>::assign+0x98 boost::basic_regex<int,boost::icu_regex_traits>::do_assign+0x14c boost::basic_regex<int,boost::icu_regex_traits>::assign+0x16 boost::basic_regex<int,boost::icu_regex_traits>::assign<int *>+0xa2 boost::basic_regex<int,boost::icu_regex_traits>::basic_regex<int,boost::icu_regex_traits><boost::u16_to_u32_iterator<wchar_t const *,int> >+0xb8 boost::re_detail::do_make_u32regex<wchar_t const *>+0x25 boost::make_u32regex+0x2c Sergey

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Create A Boost Thread for each HW Thread?
by Brad 10 Jun '11

10 Jun '11

What's the proper way to start a boost thread for each hardware thread available? I can do this... but it is clunky and does not scale (especially when there are lots of cores): const unsigned int hwt() { const unsigned int t = boost::thread::hardware_concurrency(); return t; } if ( t == 2 ) { boost::thread _01( task, thread_data, St ); boost::thread _02( task, thread_data, St ); _01.join(); _02.join(); } if ( t == 4 ) { boost::thread _01( task, thread_data, St ); boost::thread _02( task, thread_data, St ); boost::thread _03( task, thread_data, St ); boost::thread _04( task, thread_data, St ); _01.join(); _02.join(); _03.join(); _04.join(); } It seems that a for loop (or something similar) could be used to start the same number of boost threads as there are HWTs. Could someone point me in the right direction? Thanks, Brad

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Re: [Boost-users] boost MSDN
by Tom Tan 10 Jun '11

10 Jun '11

you might want to check boost.filesystem at here: http://www.boost.org/doc/libs/1_46_1/libs/filesystem/v3/doc/tutorial.html , more specifically this part : "Directory iteration plus catching exceptions - (tut3.cpp)" boost.filesystem needs building. you could go here to get a pre-built package: http://www.boostpro.com/download/ Hope this helps. > ------------------------------ > > Message: 7 > Date: Fri, 10 Jun 2011 11:39:17 +0800 > From: Peter <lq.yan(a)siat.ac.cn> > To: boost-users(a)lists.boost.org > Subject: [Boost-users] boost MSDN > Dear all, > > I'm a newer to boost library. when i try to use the boost library to get > the files of current directory, I found it is so difficult to get some > help from boost HTML document. > Is there any document could teach me to use boost library API? Most of > time, i use visual studio, MSDN teach me how to use API. > So i think Boost maybe has similar documents to help me improving coding > speed. > -- > > *Regards, > > ??? /Peter,YAN/ > > * > > ?????????? > ????????????????? > Email: lq.yan(a)siat.ac.cn > TEL: +86 755 8639 2301 > >

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(no subject)
by Marco Piacentini 10 Jun '11

10 Jun '11

Marco Piacentini wrote: > Hy...I try to explain better my question... > Im using boost serialization text archive before sending data over > TCP connection... > Now I need to pass the received data to a Java application...so I > would know if the serialized stream is composed only by the data or > by the data + boost serialization(tag, code, etc.)... > In this case my only chance to transfer the data to the java > application, is to filter them before transfering?thanks... Robert Ramey wrote: >I'll try to answer the question - but I'm sort of speculating as to what >you want to do. I throw in some miscellanous observations which >may or may not be helpful. >a) Generally I don't suggest that one tries to use boost serialization >to export data to non C++ applications. The library is intended to >provide the easiest to use and most efficient implementation of >serialization for C++ environments. Any ability to use this to >export data to/from other environments is a coincidence. >b) There are other tools for accomplishing the above. There >is google protocol buffers and there is boost spirit/karma/qi >which handle data in a way that is not connected to C++. Of >course they won't be as automatic as serialization for just this >reason. >large part it consists of not using those parts of the library which >are strongly dependent C++ such as serialization of pointers. A >useful place to start is one of the examples included with the package >which creates a write only archive which can export any data which >includes serialization functions. The leverages the serialization functions >to save a lot of work at the expense of being to read the archive back. >Something like might work for you. >d) there are other examples around for serializing files with JSON >and YAML formats. Again, these would likely mean not using >some of the features of the serialization library - which might be >be fine for you app. >I realize this might not be much comfort - but hope it helps >anyway. Thanks...unfortunately the analisys and design phases was very poor in the project in which I work....I'll try to follow your advices...bye!

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boost build and link problems
by Littlefield, Tyler 10 Jun '11

10 Jun '11

Hello all: I'm trying to use boost::asio in an app. I used the bootstrap.bat and then bjam to build and configure boost. I use the visual studio 2008 command prompt because when I run bootstrap.bat from the normal command prompt, I get: cl.exe - System Error The program can't start because mspdb100.dll is missing from your computer. Try reinstalling the program to fix this problem. the build is building vc100 libs, but when I try to build my app it's trying to link to vc90 libs. I am using 2008, so I am confused as to why this is working out to build vc100 libs. When I build: 1>LINK : fatal error LNK1104: cannot open file 'libboost_system-vc90-mt-gd-1_46_1.lib' so it looks like it's trying to link to vc90 libs when vc100 are all that's being built. Is there a way to get rid of this and build for vs 2008? -- Take care, Ty my website: http://tds-solutions.net blog: http://tds-solutions.net/blog skype: st8amnd127 My programs don't have bugs; they're randomly added features!

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Asio SSL verify peer
by Lloyd 10 Jun '11

10 Jun '11

Hi, Checking asio::ssl sample, the client side code contains a way to verify the server certificate as ctx.set_verify_mode(boost::asio::ssl::context::verify_peer); ctx.load_verify_file("ca.pem"); What parameters are checked by this function? Is it possible to check the parameters in certificate file manually? (I have gone through openssl manual, it seems openssl has functions for that) And also how can I do a client authentication using SSL? Thanks a lot, Lloyd

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enable_shared_from_this::weak_from_this() request
by Marat Abrarov 10 Jun '11

10 Jun '11

Hi, boost users and experts. I often use boost::enable_shared_from_this. I know - it contains boost::weak_ptr, which is initiated in the details of boost::shared_ptr's constructor. Also sometimes I need function weak_from_this() at the classes derived from boost::enable_shared_from_this. For now I use something like: class my_class : public boost::enable_shared_from_this<my_class> , private boost::noncopyable { ...somewhere in my_class details... private: typedef my_class this_type; typedef boost::weak_ptr<this_type> this_type_weak_ptr; this_type_weak_ptr weak_from_this() { return this_type_weak_ptr(shared_from_this()); } }; // my_class But as I know restoring shared_ptr from weak_ptr (done in shared_from_this()) is quite expensive. So my_class::weak_from_this() does unnecessary work instead of just copy internal weak_ptr stored in enable_shared_from_this. So the question is: why there is no weak_from_this() member function in boost::enable_shared_from_this class? Regards, Marat Abrarov.

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Boost.Log V1. error on QNX6.4 "boost::filesystem::create_directories: File exists: "blabla"
by Jinqiang Zhang 10 Jun '11

10 Jun '11

The "blabla" in title is the path where I ran the application I got this exception when trying to logging first record. The console log shows up then the exception thrown. In initializing code, I create an boost::log::sinks::text_file_backend with a parameter "boost::log::keywords::file_name = logs/%Y-%m-%d_%H-%M-%S-%N.log" I tested the same code on Windows XP and Linux(Debian), it works. help please. Jinqiang ZHANG

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