April 2010 - Boost-users - lists.preview.boost.org

[Spirit?] core dump in endl?
by philip tucker 12 Apr '10

12 Apr '10

Hello, I enclose a Spirit parser with two BOOST_FOREACH loops, one of which works and the other coredumps. I also enclose a gdb backtrace. Can you explain what's going on here? TIA

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compiler error with Phoenix and zip_iterator
by Surya Kiran Gullapalli 12 Apr '10

12 Apr '10

The following piece of code works fine with MSVC 9.0 but fails with Gcc-4.4.2. Compiler throws lot of error messages due to the for_each call. I'm unable to figure out the exact problem ================== #include <vector> #include <string> #include <iostream> #include <sstream> using namespace std ; #include <boost/spirit/include/phoenix.hpp> namespace phx = boost::phoenix ; namespace pha = phx::arg_names ; #include <boost/iterator/zip_iterator.hpp> #include <boost/assign.hpp> using namespace boost::assign ; void updateOut (const boost::tuple<const string&, const int&>& p_tuple, vector<string>& p_out) { ostringstream os ; os << p_tuple.get<0>() << '-' << p_tuple.get<1>(); p_out += os.str() ; } int main (void) { vector<string> vs, out ; vector<int> vi, vi2 ; vs += "String", "String", "String", "String", "String"; vi += 1,2,3,4,5 ; vector<string>::const_iterator sbegIter = vs.begin(); vector<string>::const_iterator sendIter = vs.end(); vector<int>::const_iterator ibegIter = vi.begin(); vector<int>::const_iterator iendIter = vi.end(); std::for_each ( boost::make_zip_iterator(boost::make_tuple(sbegIter, ibegIter)), boost::make_zip_iterator(boost::make_tuple(sendIter, iendIter)), phx::bind (&updateOut, pha::arg1, phx::ref(out)) ) ; } ============ I'm using Boost-1.42.0 What is wrong with for_each call ? Thanks in advance, Surya

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[serialization] vector with custom allocator
by Kenny Riddile 12 Apr '10

12 Apr '10

What would be the easiest way to serialize a std::vector that uses a custom allocator type?

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warning in boost concept
by oberhoff 12 Apr '10

12 Apr '10

Hi, this is using boost 1.42, I think the same happens in 1.43 Using boost::accumulators generates a compiler warning in boost/concept_check.hpp:335. it seems the Arg member is a reference, but gcc doesnt like that there is no way to initialize it since it is private and the class does not have a constructor. this is particularly annoying since due to metaprogramming and the lag of variadic templates the instantiation trace in the error message for a single error is a few pages long, and it comes each time I instantiate an accumulator. is there a way to avoid this? Best Daniel

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Re: [Boost-users] Possible bug: regex, lexical_cast
by John.X.Foster＠nab.com.au 12 Apr '10

12 Apr '10

Hi all Having done some further research, I suspect this is NOT a boost bug, but is a bug in the microsoft implementation of ostringstream (which I suspect is used for the string concatenation). Replacing ostringstream with boost::format has resulted in several bugs with the same general charateristics disappearing! John John Foster Senior Quantitative Credit Developer Model Development, Group Credit Portfolio & Models National Australia Bank Level 15, 500 Bourke St, Melbourne VIC 3000 Tel: +61 (0)3 8641 5228 Email: John.X.Foster(a)nab.com.au This e-mail is sent by or on behalf of the named sender identified above. If: (a) you do not wish to receive any e-mail marketing material from this person in the future, please forward the contents of this email to unsubscribe(a)nab.com.au with the word "unsubscribe" in the subject box. (b) you wish to unsubscribe from all central e-mail marketing lists used by our business, please forward the contents of this e-mail to unsubscribeall(a)nab.com.au with the message "unsubscribe from all central e-mail marketing lists" in the subject box. If you do not forward the contents of this e-mail with your unsubscription then it may not be able to be implemented. The information contained in this e-mail communication may be confidential. You should only read, disclose, re-transmit, copy, distribute, act in reliance on or commercialise the information if you are authorised to do so. If you are not the intended recipient of this e-mail communication, please immediately notify us by e-mail to postmaster(a)nab.com.au, or reply by e-mail direct to the sender and then destroy any electronic and paper copy of this message. Any views expressed in this e-mail communication are those of the individual sender, except where the sender specifically states them to be the views of a member of the National Australia Bank Group of companies. Any advice contained in this e-mail has been prepared without taking into account your objectives, financial situation or needs. Before acting on any advice in this e-mail, National Australia Bank Limited recommends that you consider whether it is appropriate for your circumstances. If this e-mail contains reference to any financial products, the National recommends you consider the Product Disclosure Statement (PDS) or other disclosure document before making any decisions regarding any products. The National Australia Bank Group of companies does not represent, warrant or guarantee that the integrity of this communication has been maintained nor that the communication is free of errors, virus or interference.

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[math/distributions] calculating p-value?
by Christian Meesters 11 Apr '10

11 Apr '10

Hi, Having a test which values are chi^2-distributed, I tried to calculate a p-value and utterly failed. My code, so far: #include <boost/math/distributions/chi_squared.hpp> using boost::math::chi_squared; <snip> chi_squared dist(N - 1); p = cdf(complement(dist, (std::fabs(beta)))) ; Here, N is the sample size and beta my beta-estimate. Reading Numerical Recipies my approach might be a bit naive, yet is there any short hand using boost? (Or am I making a stupid mistake here? Which?) TIA Christian

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[asio] What happens when socket receive buffer overflows?
by Matheus Araújo Aguiar 11 Apr '10

11 Apr '10

Hello List, I have a network application written with asio that uses TCP. The message exchange between client and server is done using a protocol that puts a prefix on each message indicating the number its bytes number. This way, at one side a prefix is read, and the number of bytes indicated in the prefix is read as a message, then it reads another prefix and so on. While testing the application I was having some errors related to reading a prefix that would indicate a strange number of bytes incoming, a number that was far greater than the max size possible of message in my protocol. After assuring that the bytes on the stream were not being merged, i started suspecting about socket buffer size. So i reduced the socket buffer size to 1K, and the application crashed with a lot less network load than before. At the moment, i am almost sure that the problem is the socket receive buffer which overflows and the bytes are discarded, creating a "gap" in the byte stream which causes an inconsistent state on the application. Does that make sense? What should happen when the socket receive buffer overflows? It silently discards the bytes or what? Thanx for your attention, -- Matheus Araújo Aguiar Computer Scientist matheus.pit(a)gmail.com

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compiling boost::asio w/ SSL
by David Kaplan 11 Apr '10

11 Apr '10

It seems that i have compiled boost::asio without SSL or something but whatever I do I cannot seem to get my previously perfectly compiling app to compile again. I get a bunch of errors such as: ‘SSL’ has not been declared app line 121, external location: /usr/local/include/boost/asio/ssl/detail/openssl_operation.hpp ‘struct boost::asio::ssl::detail::openssl_stream_service::impl_struct’ has no member named ‘ext_bio’ app line 195, external location: /usr/local/include/boost/asio/ssl/detail/openssl_stream_service.hpp ‘ssl_bio_’ was not declared in this scope app line 168, external location: /usr/local/include/boost/asio/ssl/detail/openssl_operation.hpp ‘::SSL’ has not been declared app line 37, external location: /usr/local/include/boost/asio/ssl/detail/openssl_operation.hpp etc. etc. etc. Any ideas?

1 1

How to serialize basic_string<unsigned char>
by Martin Dietze 10 Apr '10

10 Apr '10

I want to serialize an existing (low level) class which uses a `std::basic_string<unsigned char>' as member variable. Compiling the code (boost/serialization/string.hpp is included) fails with this message: /usr/include/boost/serialization/access.hpp:109: error: ‘class std::basic_string<unsigned char, std::char_traits<unsigned char>, std::allocator<unsigned char> >’ has no member named ‘serialize’ As I understand, std::string is now treated as a simple data type, but std:basic_string<unsigned char> is not. Is there already existing support for such instanciations of std::basic_string? Any hint on what I can do to get this working? Cheers, M'bert -- ----------- / http://herbert.the-little-red-haired-girl.org / ------------- =+= Warum geht ein Bratscher nicht �ber einen Friedhof? Zu viele Kreuze...

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Distinct elements in a std::vector<T>
by Hicham Mouline 10 Apr '10

10 Apr '10

Hello, Given a std::vector<T> and a Compare<T> comparator, how can I: 1. determine the number of different elements in the vector? 2. get iterators to the list of distinct elements in the vector? My naive implementation for 1 is: /// v is const-ref to a std::vector<T> std::vector<T>::size_type distinct = v.empty()? 0: 1; std::vector<T>::const_iterator j; for (std::vector<T>::const_iterator i = v.begin()+1; i!=v.end(); ++i) { j = std::find(v.begin(), i, *i, Compare<T>()); if (j!=i) ++distinct; } Obviously, this is of worst order n*(n+1)/2. I'm sure a better order can be achieved. I don't quite see how to do 2. Does anything in the C++ std lib or boost facilitate this? Regards,

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