December 2010 - Boost-users

12 Dec '10

Sorry if this is a basic c++ misunderstanding on my part, but why does this compile, since there is no using in this code and to_iso_string is in namespace boost::gregorian? #include <boost/date_time/gregorian/formatters.hpp> #include <iostream> int main(int argc, char** argv) { boost::gregorian::date d(2010, 1, 1); std::cout << to_iso_string(d) << std::endl; std::cout << to_iso_extended_string(d) << std::endl; std::cout << to_simple_string(d) << std::endl; return 0; } ------------------------------ g++ to_iso_string.cpp -I../boost_1_44_0/include -L../boost_1_44_0/lib - lboost_date_time-mt Thanks Dan

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NewBie: help needed generating documentation with quickbook and bjam
by Prof. Dr.-Ing. Wilhelm Meier 12 Dec '10

12 Dec '10

Hello, this is a absolute newbie question: I try to write some documentation using quickbook. I was able to generate a .xml file. But now I have no idea how to produce a html or pdf version thereof. I read some documentation about bjam and installed the neccessary libraries (I hope). But I didn't find any documentation about how to write a .jam file for this purpose. Can someone help solving this (dumb) question? -- Wilhelm

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serialization: pointers to base classes
by Hicham Mouline 11 Dec '10

11 Dec '10

Hello, I am unclear about registration and export. I have this public single-derivation hierarchy B | \ \ D1 D2 D3 | D11 The 5 structs are non abstract. I will want to serialize (save) const B* and load it back with the serialization lib constructing for me (on the heap) the right object. Did I understand right that the library does this for me? Does it construct the object on the heap? I export the 5 structs with the macro BOOST_CLASS_EXPORT_GUID(ns::B, "B") at global namespace level. Do I have to register them too? template <class Archive> void serialize(Archive &ar, ns::B&, const unsigned int version) { ar.template register_type<D1>(); ar.template register_type<D2>(); ar.template register_type<D3>(); ar.template register_type<D11>(); } or do I register for each class only the immediate derived? regards,

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[BoostCon 2011] 2nd Call for participation
by Hartmut Kaiser 11 Dec '10

11 Dec '10

Hey all, please find below the updated CfP for BoostCon 2011. Note, we extended the submission deadline. The new submission deadline is January, 10th 2011. ----------------------------------------------------------------- 5TH ANNUAL BOOST CONFERENCE 2011 Aspen CO, USA, May 15 - 20, 2011, www.boostcon.com CALL FOR PARTICIPATION We invite you to submit session proposals to the 5th Annual Boost Conference: BoostCon 2011 (Aspen CO, USA, May 15 - 20, 2011). Traditionally the main face-to-face event for all things Boost (www.boost.org) BoostCon 2011 will present leading speakers from the whole C++ community. From using the Boost libraries to writing and maintaining them, from evangelizing to deploying Boost within your organization, from infrastructure and process to vision and mission, and the new C++ Standard, BoostCon brings together the sessions, the colleagues, and the inspiration to support your work with C++ and Boost in particular for the next year. To reflect the breadth of the Boost community, the conference includes sessions aimed at three constituencies: Boost end-users, hard-core Boost library and tool developers, and academics focusing on research. The program fosters interaction and engagement within and across those groups, with an emphasis on hands-on, participatory sessions. SESSION TOPICS Topics of interest include, but are not restricted to, the following: * General tutorial sessions introducing one or more Boost libraries * In-depth sessions on using specific Boost libraries * Case studies on using Boost * Experts panels * Advanced sessions on implementation techniques used within Boost libraries * C++0x and how it changes life for users and library writers * Development workshops to extend or enhance existing Boost libraries * Workshops on design process * Infrastructure workshops such as Build tools, Website, Testing * Concepts and Generic Programming * Hardware and infrastructure presentations focused on how libraries can make better use of the technology * Software development tools and their application to C++ and or Boost * Other topics likely to be of great interest to Boost users and developers Interactive and collaborative sessions are encouraged, as this is the nature of both the on-line Boost community and the style of learning and participation that has proven most successful at such events. Sessions can be tutorial based, with an emphasis on interaction and participant involvement, or workshop based, whether hands-on programming or paper-based, discussion-driven collaborative work. SESSION FORMATS Presentations ------------- Presentations focus on a practitioner's ideas and experience with anything relevant to Boost and Boost users. Panels ------------- Panels feature three or four people presenting their ideas and experiences relating to Boost's relevant, controversial, emerging, or unresolved issues. Panels may be conducted in several ways, such as comparative, analytic, or historic. Tutorials ------------- Tutorials are sessions at which instructors teach conference participants specific Boost-relevant skills. Workshops ------------- Workshops provide an active arena for advancements in Boost-relevant topics. Workshops provide the opportunity for experienced practitioners to develop new ideas about a topic of common interest and experience. Author's Corner Presentations ------------- These were introduced at BoostCon 2008, and were a great success. They are short (30 minute) sessions, focusing on tips on usage and design. In addition, we're looking to uncover the hidden design gems in Boost libraries. Tool Vendors Presentations ------------- We actively encourage tool vendors and ISP's to submit proposals for a special Tool Vendors Session Track aimed at products related to Boost and C++ (compilers, libraries, tools, etc.). Other formats may also be of interest. Don't hold back a proposal just because it doesn't fit into a pigeonhole. SUBMITTING A PROPOSAL Standard Sessions are 90 minutes. You may submit a proposal for fractions or multiples of 90-minutes. Fractional proposals will be grouped into 90 minute sessions covering related topics. Longer sessions, such as tutorials and classes, will be assigned 90 minute, three hour (i.e. half day), or six hour (i.e. full day) time slots. Please include: * The working title. * Type of session: presentation, panel, tutorial, workshop, authors corner, vendor track, other. * A paragraph or two describing the topic covered, suitable for the conference web site. * Proposed length: 10-20 minute short talks, 45 minutes, 90 minutes, half day, full day. * Alternate lengths, if you are willing to make adjustments: 10-20 minute short-talks, 45 minutes, 90 minutes, half-day, full day. * Audience: users, developers, both. * Level: basic, intermediate, advanced. * A biography, suitable for the conference web site. * Your contact information (will not be made public). SUBMISSION DETAILS All submissions have to be done through the EasyChair conference management system: http://www.easychair.org/conferences/?conf=boostcon2011. If you have not already registered at EasyChair, you will need to do so in order to submit your proposal. All submissions will go through a peer review process. Authors are invited (but are not required) to submit PDF versions of full papers of up to 10 pages in ACM conference proceedings format (see http://www.acm.org/sigs/publications/proceedings-templates) The full papers are not required unless you want them published in the proceedings. All accepted proposals will be made available in the Association for Computing Machinery (ACM) Digital Library (approval pending). Best papers, after further reviews, will be considered to be book chapters or journal articles in a renowned journal. The session materials go on the BoostCon website and will be available to attendees. For general information on the BoostCon 2011 paper submission or the scope of technical papers solicited, please refer to the conference website at www.boostcon.com. For any other questions about the submission process or paper format, please contact the Program Committee at boostcon2011(a)easychair.com. If you have any technical problems with EasyChair, please contact EasyChair for help. Note: Presenters must agree to grant a non-exclusive perpetual license to publish submitted materials, either electronically or in print, in any media related to BoostCon. IMPORTANT DATES New proposal submissions due: January 10th, 2011. Proposals decisions sent (tentative program): February 17th, 2011. Fully scheduled program available: February 25th, 2011. Session materials due: April 15th, 2011. Hartmut Kaiser: hartmut.kaiser(a)gmail.com (Program Committee Chair) David Abrahams: dave(a)boostpro.com (Conference Chair) On behalf of the conference organizers

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Conversion warning from boost/functional/hash/detail/hash_float_generic.hpp
by Greg Ward 11 Dec '10

11 Dec '10

Hi all -- I'm getting a strange warning from <boost/functional/hash/detail/hash_float_generic.hpp>. What's strange is not the warning, but the circumstances: if I use the boost headers installed in /usr/include, no warning. But if I make a copy of /usr/include/boost and tell the compiler to use the copy, I get a warning. I can reproduce this on CentOS 5 using our custom build of GCC 4.4.4 and boost 1.44.0, and on Ubuntu 10.04 (lucid) using Ubuntu's builds of GCC 4.4.3 and boost 1.40.0. It doesn't take much code to reproduce the problem: $ cat test.cpp #include <boost/functional/hash.hpp> First, a good build using Ubuntu /usr/bin/g++ (4.4.3) and /usr/include/boost (1.40.0) $ /usr/bin/g++ -Wall -Wconversion -c test.cpp -o test.o [no warnings] Now let's make a copy of the boost headers and use the copy: $ mkdir include $ cp -rp /usr/include/boost include/. $ /usr/bin/g++ -Wall -Wconversion -I include -c test.cpp -o test.o In file included from include/boost/functional/hash/detail/hash_float.hpp:30, from include/boost/functional/hash/hash.hpp:15, from include/boost/functional/hash.hpp:6, from test.cpp:1: include/boost/functional/hash/detail/hash_float_generic.hpp: In function ‘size_t boost::hash_detail::float_hash_impl2(T) [with T = float]’: include/boost/functional/hash/detail/hash_float_generic.hpp:84: instantiated from ‘size_t boost::hash_detail::float_hash_impl(T) [with T = float]’ include/boost/functional/hash/detail/hash_float.hpp:74: instantiated from ‘size_t boost::hash_detail::float_hash_value(T) [with T = float]’ include/boost/functional/hash/hash.hpp:282: instantiated from here include/boost/functional/hash/detail/hash_float_generic.hpp:59: warning: conversion to ‘float’ from ‘size_t’ may alter its value include/boost/functional/hash/detail/hash_float_generic.hpp:84: instantiated from ‘size_t boost::hash_detail::float_hash_impl(T) [with T = float]’ include/boost/functional/hash/detail/hash_float.hpp:74: instantiated from ‘size_t boost::hash_detail::float_hash_value(T) [with T = float]’ include/boost/functional/hash/hash.hpp:282: instantiated from here include/boost/functional/hash/detail/hash_float_generic.hpp:71: warning: conversion to ‘float’ from ‘size_t’ may alter its value I get the same behaviour if include/boost is a symlink to /usr/include/boost. Changing "-I include" to an absolute path ("-I `pwd`/include") makes no difference. If I repeat the experiment on my CentOS 5 machine with custom builds of more recent versions of GCC (4.4.4) and boost (1.44.0), I see the same thing. The line numbers are slightly different: In file included from include/boost/functional/hash/detail/hash_float.hpp:30, from include/boost/functional/hash/hash.hpp:15, from include/boost/functional/hash.hpp:6, from test.cpp:1: include/boost/functional/hash/detail/hash_float_generic.hpp: In function ‘size_t boost::hash_detail::float_hash_impl2(T) [with T = float]’: include/boost/functional/hash/detail/hash_float_generic.hpp:82: instantiated from ‘size_t boost::hash_detail::float_hash_impl(T) [with T = float]’ include/boost/functional/hash/detail/hash_float.hpp:74: instantiated from ‘size_t boost::hash_detail::float_hash_value(T) [with T = float]’ include/boost/functional/hash/hash.hpp:315: instantiated from here include/boost/functional/hash/detail/hash_float_generic.hpp:56: warning: conversion to ‘float’ from ‘size_t’ may alter its value include/boost/functional/hash/detail/hash_float_generic.hpp:82: instantiated from ‘size_t boost::hash_detail::float_hash_impl(T) [with T = float]’ include/boost/functional/hash/detail/hash_float.hpp:74: instantiated from ‘size_t boost::hash_detail::float_hash_value(T) [with T = float]’ include/boost/functional/hash/hash.hpp:315: instantiated from here include/boost/functional/hash/detail/hash_float_generic.hpp:69: warning: conversion to ‘float’ from ‘size_t’ may alter its value but obviously the trace through the header files is basically the same. Any clues? Google did not turn up any similar problems from anyone else. Oh yeah: if you're wondering why I want to use a copy of (or symlink to) the real boost installation, it's because we need to support building many different versions of our software, and they don't all use the same versions of boost or gcc (or various other 3rd-party components). So each build tree has a bunch of local symlinks pointing to exactly the right versions of gcc, boost, etc. Thanks! Greg

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mpi: is_mpi_datatype
by Hicham Mouline 11 Dec '10

11 Dec '10

Hello A polymorphic struct with 2 doubles and 1 virtual function is not intended to be marked as is_mpi_datatype : mpl_true, is it? regards,

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Problem compiling: 64bit, link=shared, runtime-link=shared
by Thomas 11 Dec '10

11 Dec '10

Hallo, I need help compiling boost. My setup: Windows SDK v7.0 Boost 1.45 My configuration: bjam --prefic=c:\boost --with-thread --with-system --with-filesystem --with-program_options --with-date_time link=shared threading=multi address-model=64 runtime-link=shared toolset=msvc stage in boost/config/user.hpp I activated #define BOOST_ALL_DYN_LINK Linking fails with: thread.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl boost::gregorian::greg_month::greg_month(unsigned short)" (__imp_??0greg_month@gregorian@boost@@QEAA@G@Z) referenced in function "public: __cdecl boost::gregorian::date::date(enum boost::date_time::special_values)" (??0date@gregorian@boost@@QEAA@W4special_values@date_time@2@@Z) bin.v2\libs\thread\build\msvc-9.0\release\address-model-64\threading-multi\boost_thread-vc90-mt-1_45.dll : fatal error LNK1120: 1 unresolved externals Thanks!

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Range - Char literal question
by Rao, Anant 10 Dec '10

10 Dec '10

Hi, I need to iterate thru strings (For various reasons, I can't use string or vector<char> containers). I found that boost::range exactly fits the bill for me. I get all the convenience of an iterator (from as_literal.hpp). I have a piece of code char* char_s = "I am fine"; char *cp; std::size_t sz = strlen(char_s); const char* str_end1 = str_begin( char_s ) + sz; for (cp = str_begin(char_s); cp != str_end(char_s); ++cp) cout << *cp; I have couple of questions: 1. In the loop, boost::range seems to be calling strlen every iteration. This is an overhead. I was wondering if there's a way I can pass in the length myself so that boost::range would use it and avoid calling strlen(). 2. If it's not possible, is there a way for me to use iterators (boost or non-boost) over char strings? Thanks so much in advance for your help, Anant The information contained in this email message and its attachments is intended only for the private and confidential use of the recipient(s) named above, unless the sender expressly agrees otherwise. Transmission of email over the Internet is not a secure communications medium. If you are requesting or have requested the transmittal of personal data, as defined in applicable privacy laws by means of email or in an attachment to email, you must select a more secure alternate means of transmittal that supports your obligations to protect such personal data. If the reader of this message is not the intended recipient and/or you have received this email in error, you must take no action based on the information in this email and you are hereby notified that any dissemination, misuse or copying or disclosure of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by email and delete the original message.

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[Units] derived units of SI system (newbie)
by André Berthe 10 Dec '10

10 Dec '10

Dear List, I would like to calculate a shear stress based on a shear rate and a viscosity using Boost.Units. Here I have problems using derived dimensions and conversion factors based on a existing system. The error messages of my compiler are in German, so I tried to document my problems with a test code: <main.cpp> #include <boost/units/systems/si/dynamic_viscosity.hpp> #include "stress.h" #include "shearrate.h" namespace bu = boost::units; namespace SI = bu::si; main(){ //Define a quantity of unit stress. Unfortunately there is no //realization of the defined physical dimension stress in si. //So a user defined type from stress.h (see below) is used: bu::quantity<SI::stress> WSS_x; //Define a shear rate. I did not understand how to use a //inverse time as dimension. Therefore I defined the derived //dimension per_time in shearrate.h. Is it possible to add it to //the si system (as I tried) or do I have to define //my own system and a conversion factor? bu::quantity<SI::per_time> WSR_x(1*per_second); //There is a existing si type for the dynamic viscosity. //However, there is no defined constant. How is the //correct way to assign a value? Should I define this //constant? bu::quantity<SI::dynamic_viscosity> eta; //Calculation of the shear stress. It seems that this calculation //tries to use a »sizeof« on eta, that seems to have a // incomplete type //(»boost::STATIC_ASSERTION_FAILURE<false>«). And there //seems to be something wrong with the conversion. //Do I have to define a conversion factor? Or is this error //caused by my previous mistakes? WSS_x=WSR_x/eta; } </main.cpp> Included header file 1: <stress.h> #include <boost/units/systems/si/base.hpp> #include <boost/units/physical_dimensions/stress.hpp> #include <boost/units/make_system.hpp> namespace boost { namespace units { namespace si { typedef unit<stress_dimension,si::system> stress; } // namespace si } // namespace units } // namespace boost </stress.h> Included header file 2: <shearrate.h> #include <boost/units/base_dimension.hpp> #include <boost/units/derived_dimension.hpp> #include <boost/units/io.hpp> #include <boost/units/quantity.hpp> #include <boost/units/static_constant.hpp> #include <boost/units/unit.hpp> #include <boost/units/base_unit.hpp> #include <boost/units/systems/si/time.hpp> namespace boost { namespace units { namespace si { typedef derived_dimension< time_base_dimension,-1>::type per_time_dimension; // [1/m] typedef unit< si::per_time_dimension, si::system > per_time; static const per_time per_second; static const per_time per_seconds; } } } Thank you, André

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Possible bug: ostringstream
by Jammy Cheng Chen 10 Dec '10

10 Dec '10

Hi All, I have come across a bug associated the following code, it work fine in VS2008 release mode and crash in debug mode, I did some research found it should be a bug in the microsoft implementation of ostringstream, Is anybody know how to fix this or alternative way? Any ideas would be appreciated. BTW: I must use std::ostringstream because actually lot of dependencies dll was developed with std::ostringstream.str() return. I don't want change the dependencies project it wastes too much. std::string result( "" ); size_t length = source.size(); std::ostringstream offset; long offsetsToSource = 12135L; offset << offsetsToSource; std::string nsource = offset.str(); result.reserve( nsource.length() * 1.6 ); std::for_each( nsource.begin(), nsource.end(),ToXML( result, "\"&<>" ) ); msvcp90d.dll!std::_Container_base_secure::_Orphan_all() Line 223 + 0x5 bytes C++ msvcp90d.dll!std::_Container_base_secure::~_Container_base_secure() Line 115 C++ msvcp90d.dll!std::_String_base::~_String_base() + 0x11 bytes C++ msvcp90d.dll!std::_String_val<unsigned short,std::allocator<unsigned short> >::~_String_val<unsigned short,std::allocator<unsigned short> >() + 0x11 bytes C++ msvcp90d.dll!std::basic_string<char,std::char_traits<char>,std::allocato r<char> >::~basic_string<char,std::char_traits<char>,std::allocator<char> >() Line 917 + 0xf bytes C++ getMetaData.dll!getQMAttributes(Av::Generic::ContainerIF * pcFile=0x026a0924, Av::Generic::MasterMobIF * pMasterMob=0x0278d234, Av::Generic::TapeMobIF * pTapeMob=0x0279275c, MobInfo & mobInfo={...}) Line 748 + 0x73 bytes C++

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