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[asio] : how to monitor a tcp socket
by Mathieu Peyréga 06 Nov '08

06 Nov '08

Hello first, thanks to boost creators for these great libraries ! For my question... I have an external TCP server, to which I connect thanks to a boost.asio powered client. I am using asynchronous operations, but i have an issue, I'd like to trigger a *fast *client side deconnexion when the peer disappear (is reset for example) So far, the deconnexion occurs on an error on a asynchronous read operation, but this error happens like 10-12 seconds after the physical deconnexion occured. Is there a way to set the "time out" value ? Is there another way to detected that the peer vanished. Regards, Mathieu

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[phoenix] std::fstream problem
by Christian Henning 06 Nov '08

06 Nov '08

Hi there, sorry to bother the community with my phoenix problems today. Please consider the following code sample: #include <boost/spirit/include/phoenix_algorithm.hpp> #include <boost/spirit/include/phoenix_bind.hpp> #include <boost/spirit/include/phoenix_container.hpp> #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/include/phoenix_function.hpp> #include <boost/spirit/include/phoenix_fusion.hpp> #include <boost/spirit/include/phoenix_object.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/include/phoenix_scope.hpp> #include <boost/spirit/include/phoenix_statement.hpp> #include <boost/spirit/include/phoenix_stl.hpp> #include <algorithm> #include <iostream> #include <fstream> #include <vector> int _tmain(int argc, _TCHAR* argv[]) { using namespace std; using namespace boost::phoenix; using namespace boost::phoenix::arg_names; vector< int > ints; ofstream out( ".\\remove.txt" ); // works std::for_each( ints.begin(), ints.end(), cout << arg1 << " " ); // doesn't work - error C2297: '<<' : illegal, right operand has type 'const char *' std::for_each( ints.begin(), ints.end(), out << arg1 << " " ); return 0; } I couldn't find anything inside the documentation regarding file streams. Thanks, Christian

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Boost 1.37.0 Release Notice
by Beman Dawes 06 Nov '08

06 Nov '08

Boost 1.37.0 has been released and is available from SourceForge. See http://sourceforge.net/projects/boost/ This release includes one new library: Proto: Expression template library and compiler construction toolkit for domain-specific embedded languages, from Eric Niebler. Updated libraries include Asio, Circular Buffer, Dynamic Bitset, Hash, Interprocess, Intrusive, Math Type, Traits, and Unordered. The release managers were Beman Dawes, Daniel James, Eric Niebler, and Rene Rivera. The web site should be updated soon to reflect the new release. If you can't wait, see http://beta.boost.org now! --Beman Dawes

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Re: [Boost-users] shared_ptr and Visual Studio 2008 Express SP1
by Sergey Sadovnikov 06 Nov '08

06 Nov '08

Hello, John. Wednesday, November 5, 2008 at 7:37:00 PM you wrote: JM> Nothing unusual about that: you have two different shared_ptr's visible in JM> scope: boost::shared_ptr and std::tr1::shared_ptr. You need to decide which JM> you intend to use and either prefix all shared_ptr usages with the JM> appropriate qualifiers, or else just take care to only import the one JM> shared_ptr in the first place. I understand what I have two visible versions of shared_ptr. And in my code I exclude all "boost/shared_ptr.hpp" inclusions. But what I have to do with boost headers such as "date_time/gregorian/greg_month.hpp" which also include shared_ptrs? I understand, what 'using' is quite dangerous directive, but I use it only in implementation files and never in headers. It makes source code more shortly and readable. Just compare: std::tr1::bind(&std::tr1::shared_ptr<SomeType>::get, std::tr1::placeholders::_1, /* ... */); with bind(&shared_ptr<SomeType>::get, _1); :) In the first case code semantic hidden under fully-qualified names. -- Best Regards, Sergey mailto:ssadovnikov@egopolis.com

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error C2440: 'reinterpret_cast' : InterlockedCompareExchange from detail\interlocked.hpp
by Joseph Marks 06 Nov '08

06 Nov '08

Apparently, the signature of this function has changed. When we used it under Visual Studio 6.0 it compiled correctly however, the following happens in MS VS 2008: The following error appears error C2664: 'InterlockedCompareExchange' : cannot convert parameter 2 from 'PVOID' to 'LONG' If I just do a cast, I get: error C2440: 'reinterpret_cast' : cannot convert from 'DWORD' to 'long'. Does anyone have any suggestions? Thanks in advance. Joseph (-: The preceding e-mail message (including any attachments) contains information that may be confidential, or constitute non-public information. It is intended only for the designated recipient. If you are not the named addressee, you should not disseminate, distribute or copy this e-mail. If you have received this e-mail by mistake, please notify the sender immediately by replying to this message and delete this e-mail from your system. Use, dissemination, distribution or reproduction of this message by unintended recipients is not authorized and may be unlawful.

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Boost Statechart Keyboard and Pingpong example code?
by framebuffer 06 Nov '08

06 Nov '08

Hi, Please refer to the following link: http://www.boost.org/doc/libs/1_35_0/libs/statechart/doc/tutorial.html The tutorial refers to two source codes : for eg: in Asynchronous state machines "see the PingPong example for the full source code" I am unable to locate these example (keyboard and pingpong). I googled it, and no links are given in the tutorial. Thanks, fb. -- View this message in context: http://www.nabble.com/Boost-Statechart-Keyboard-and-Pingpong-example-code--… Sent from the Boost - Users mailing list archive at Nabble.com.

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[date_time] dst_local_start_time
by Jean-Pierre Bergamin 06 Nov '08

06 Nov '08

Hello I'm confused about the returned time of the dst_local_start_time() function. First of all I don't understand why a ptime is returned and not a local_date_time, buy anyway. The ptime I get returned for the timezone Europe/Zurich for 2007 is: 2007-Mar-25 02:00:00 Assuming that this is a UTC time, the local time in Zurich would then be 2007-Mar-25 04:00:00 (because during summertime, Zurich is 2h ahead of UTC), but the correct local dst start time would be 2007-Mar-25 03:00:00 (because the clocks are shifted from 2 to 3). To correctly calculate the dst start time, I have to add the dst_offset to the returned time_of_day. The returned ptime 2007-Mar-25 02:00:00 seems to be the endtime of wintertime as a local time. time_zone_ptr zh_tz = tz_db.time_zone_from_region("Europe/Zurich"); ptime zh_dst_start_time = zh_tz->dst_local_start_time(2007); std::cout << zh_dst_start_time << std::endl; // 2007-Mar-25 02:00:00 local_date_time zh_dst_local_start_time = local_date_time(zh_dst_start_time, zh_tz); std::cout << zh_dst_local_start_time << std::endl; // 2007-Mar-25 04:00:00 CEST which is wrong! ptime zh_dst_start_time_ok = zh_dst_start_time + zh_tz->dst_offset(); local_date_time zh_dst_local_start_time_ok = local_date_time(zh_dst_start_time_ok.date(), zh_dst_start_time_ok.time_of_day(), zh_tz, true); std::cout << zh_dst_local_start_time_ok << std::endl; // 2007-Mar-25 03:00:00 CEST which is correct So what time exactly is local_start_time() returning? Is this a bug or am I missing something? Regards James

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[Lambda] Using placeholders as array indices
by user790 user790 06 Nov '08

06 Nov '08

I am trying to use boost::lambda's placeholders as array indices. What I tried boils down to this: <code> #include <vector> #include <boost/lambda/bind.hpp> #include <boost/lambda/lambda.hpp> int main(int argc, char * argv[]) { using namespace boost::lambda; std::vector<int> a(10,0); bind(static_cast<std::vector<int>::reference (std::vector<int>::*)(std::vector<int>::size_type)>(&std::vector<int>::operator[]), a, _1)(0) = 1; } </code> But I get the following error (Visual C++ 2008 Express Edition, boost 1.35.0): error C2665: 'boost::lambda::function_adaptor<Func>::apply' : none of the 2 overloads could convert all the argument types What part am I missing? Thanks, P.

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Assertion 'px != 0' failed when using boost::regex
by Daniel Hansen 06 Nov '08

06 Nov '08

Hey everyone, I'm in desperate need of some help here. I'm working on a webcrawler for a computer science class and I'm using boost::regex to parse some of the html elements. After calling a few boost::regex functions, I get this error. It doesn't seem to be tied to any specific funcion, but it seeems to come up after a certain number of calls to the functions. Here is the exact error: test: /usr/include/boost/shared_ptr.hpp:315: T* boost::shared_ptr<T>::operator->() const [with T = boost::regex_token_iterator_implementation<__gnu_cxx::__normal_iterator<const char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >]: Assertion `px != 0' failed. and the backtrace: #0 0x00110416 in __kernel_vsyscall () #1 0x005424c0 in raise () from /lib/libc.so.6 #2 0x00543e88 in abort () from /lib/libc.so.6 #3 0x0053b3fe in __assert_fail () from /lib/libc.so.6 #4 0x0806228f in boost::shared_ptr<boost::regex_token_iterator_implementation<__gnu_cxx::__normal_iterator<char const*, std::string>, char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > >::operator-> (this=0xbfffef04) at /usr/include/boost/shared_ptr.hpp:315 #5 0x080622a7 in boost::regex_token_iterator<__gnu_cxx::__normal_iterator<char const*, std::string>, char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::operator* (this=0xbfffef04) at /usr/include/boost/regex/v4/regex_token_iterator.hpp:243 #6 0x080582cd in HTMLParser::parse I have attached my code, so that you can see what functions I'm using and in what context, etc. I really appreciate all your help. Thanks, Daniel Hansen

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Boost::Serialize, serializing std::basic_string
by Jacob Holm 06 Nov '08

06 Nov '08

I have a variable which is a basic_string, as I want my own allocator assigned to it. This gives me the following compiler error: "Error 3 error C2039: 'serialize' : is not a member of 'std::basic_string<_Elem,_Traits,_Ax>' ...\boost\serialization\access.hpp 109" I have searched around for this error but have not been able to find a solution. It would be possible to just pass a vector with chars in it, but basic_string is preferred. Has anyone else had this problem and maybe managed to solve it? /Jacob Holm

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