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Scope exit with no capture
by Bruno Martínez 22 Nov '11

22 Nov '11

Hi, How can I call BOOST_SCOPE_EXIT when no variable needs to be captured? BOOST_SCOPE_EXIT () { CoUninitialize(); } BOOST_SCOPE_EXIT_END; doesn't work. I tried BOOST_SCOPE_EXIT (BOOST_PP_NIL) BOOST_SCOPE_EXIT (BOOST_PP_EMPTY) BOOST_SCOPE_EXIT (BOOST_PP_SEQ_NIL) but they don't work either. Bruno

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Re: [Boost-users] [Thread] program crashes from time to time when deleting unique_future<void>
by Alex Perry 22 Nov '11

22 Nov '11

On Mon, 21 Nov 2011 16:40:04 +0000 "Soderback, Johan" <Johan.Soderback(a)elekta.com> wrote :- > Hi, > > I have a small example program that crashes from time to time. > I would appreciate some help to understand why. > > In function run() executed on the main thread I create a packaged_task (pt), > put it in a queue (_q) and wait for it to get executed (fu.get()). > In another thread the tasks are executed when the queue _q is populated. > The task I'm running always throws/rethrows intentionally. > > It results (from time to time) in an access violation when the unique_future, > fu, is deleted. > See the stack trace at the bottom. > > Anybody see any flaws in this design? > > I have tried 1.47.0 and 1.48.0, MSVC 2005. > Trying your example on vs2010 it crashes continuously - changing your throwf() function to the following appears to sort it - not quite sure why a simple throw fails though - or whether this was your problem under vs2005 void throwf() { try { BOOST_THROW_EXCEPTION(TheException()); } catch (boost::exception const & ) { boost::rethrow_exception( boost::current_exception() ); } } HTH Alex

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[serialization] backwards compatibility of vector (de)s11n
by Ewald Peiszer 22 Nov '11

22 Nov '11

Hi list, I am migrating from Boost v1.35 to a new version. I have, however, some legacy serialized strings that I want to be readable by the new version. After some testing I found that apparently the newer version (in this case 1.40) cannot correctly deserialize std::vector instances from 1.35 generated strings. Can anyone give my a pointer as to what may be the problem here? Thanks a lot! Ewald ==Details== I use text archives, and gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu9) The test vector is a structure with 2 items, the long integers 1 and 2. Archive string for respective lib versions: 1.35 archive: 22 serialization::archive 4 2 1 2 1.40 archive: 22 serialization::archive 5 2 0 1 2 Now: ---------(code snippet) // includes #include <boost/serialization/vector.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> std::vector<long> testvector; std::string val = "22 serialization::archive 4 2 1 2"; // v1.35 archive { std::stringstream ss(std::stringstream::in | std::stringstream::out); ss << val << std::endl; boost::archive::text_iarchive ia(ss); ia >> BOOST_SERIALIZATION_NVP(testvector); } -------- Result when executing with lib v1.40: testvector contains two elements, {2, 2} -- instead of {1, 2} Note: s11n and de-s11n with the same lib version works perfect.

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boost.uuid typo error
by niXman 22 Nov '11

22 Nov '11

Hello list! In the docmantation for boost.uuid on this link: http://www.boost.org/doc/libs/1_48_0/libs/uuid/uuid.html#Stream_operators in the example of usage boost::lexical_cast<> with boost::uuids::uuid: boost::uuids::uuid u1; // initialize uuid std::string s = boost::lexical_cast<std::string>(u); // <<<<<<<<<<<< must be u1 boost::uuids::uuid u2 = boost::lexical_cast<boost::uuids::uuid>(s); assert(u1 == u2); I wish that boost documentation was famous as well as Qt documentation ;) Regards, niXman.

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Platform independent memory mapped [file] IO
by Steve 22 Nov '11

22 Nov '11

I have some very large (TB scale) files, and I want to map fixed-size (say 1Mb) segments from them into memory, for both reading and writing (in different contexts) making maximum use of OS-level caching. The software I'm writing needs to work under Unix/Linux and Windows... performance is critical. I've discovered boost::iostreams::mapped_file_source and boost::iostreams::mapped_file_sink, which provide most of the facilities I'm looking for. The facilities I'd like, but haven't found are: * Forcing a synchronisation of written data to disk ( msync(2) on Unix; FlushViewOfFile on Windows) * Locking files to prevent two processes attempting to write the same file at the same time (or read a newly created file before written data is flushed..) * Controlling attributes of the file at creation time (Unix) Can I do these things using boost::iostreams::mapped_file_sink and boost::iostreams::mapped_file_source? I'm aware of boost::interprocess::basic_managed_mapped_file et al, which suppors a flush() method - but I don't want to manage the files as if they were file-backed heaps... with all the space allocation that entails. I am only interested in efficiently reading/writing to fixed-size blocks of very large files (of a size known from the offset.) Am I overlooking a straightforward strategy, using the existing boost::iostreams library, to establish file-locks and to ensure only consistently written data is read by other processes? Is it appropriate to want to to force synchronisation from code as soon as all the data in a block has been written (avoiding a large latency when, say, 1GB of pages have been updated and the process needs to exit?)

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Why wasn't filesystem v2 removed in boost 1.48?
by Thomas Dziedzic 22 Nov '11

22 Nov '11

hi, I was wondering about the removal of filesystem v2 as stated on: http://www.boost.org/doc/libs/1_48_0/libs/filesystem/v3/doc/index.htm which says that filesystem v2 wont be included in boost 1.48 and later. but it seems that boost 1.48.0 still has filesystem v2 and the changelog has nothing about filesystem v2 for boost 1.48 did release guys for boost 1.48 forget to remove filesystem v2? If it was decided to keep boost filesystem v2 for 1.48, could the documentation be changed to reflect that? Thanks for your time,

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Re: [Boost-users] Boost.Locale build missing usage-requirements
by Artyom Beilis 22 Nov '11

22 Nov '11

--- On Fri, 11/18/11, Alexey Badyaev <leemouse(a)mail.ru> wrote: > From: Alexey Badyaev <leemouse(a)mail.ru> > > and user of > library must define symbol BOOST_LOCALE_DYN_LINK=1 in own > project.... Yes... Unless you integrate the full Boost tree into your project and use it directly. Which I don't see any specific reason to do. I'll review and consider adding if this **is** common and practice for boost libraries. > I wrote email to author of library (Artyom Beilis), but he > reject my > proposal of add usage-requirements to lib target. I had seen your note about useage-requirements besides and I have not responded you due the lack of time. And now you write (quoting): > he reject my proposal of add usage-requirements to lib target. This is not only **incorrect**, it is also disrespectful to behave like this and appeal to Boost community just because you had not received an answer from me withing _1_ (one) day. > May anybody with right-access to boost repository fix > this??? Now... I can tell you one thing. Do you really expect me to help you to resolve your problems after you behave this way? I'll get to check your proposal when I'll have enough time to study the issue (among other things I need to do) and I'll see if it is required. Meanwhile, patch your own code... In any case, as you told me you use Boost-Trunk, so this would not be a problem for you... Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.sf.net/ CppDB - C++ SQL Connectivity: http://cppcms.sf.net/sql/cppdb/

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Boost.Locale build missing usage-requirements
by Alexey Badyaev 22 Nov '11

22 Nov '11

Hi All. Library "Locale" from "Boost C++ Libraries" package has Jamfile.v2 in folder "build". Target "boost_locale" of library in that jam-file defined see below: lib boost_locale : encoding/codepage.cpp shared/date_time.cpp shared/format.cpp shared/formatting.cpp shared/generator.cpp shared/ids.cpp shared/localization_backend.cpp shared/message.cpp shared/mo_lambda.cpp util/codecvt_converter.cpp util/default_locale.cpp util/info.cpp util/locale_data.cpp : # Don't link explicitly, not required <define>BOOST_THREAD_NO_LIB=1 <link>shared:<define>BOOST_LOCALE_DYN_LINK=1 <threading>multi # Meanwhile remove this <conditional>@configure ; You can see: usage-requirements of target is not defined, and user of library must define symbol BOOST_LOCALE_DYN_LINK=1 in own project.... I wrote email to author of library (Artyom Beilis), but he reject my proposal of add usage-requirements to lib target. May anybody with right-access to boost repository fix this??? -- With best regards, Alexey Badyaev Russian Federation, Kemerovo

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boost MPI: unsupported functions & support on super computers ?
by Avi Bahra 21 Nov '11

21 Nov '11

I am learning MPI, and have a few questions whether its worth using boost MPI, since I need to run on many flavours of unix.(linux clusters and AIX as a minimum) o In the boost MPI documentation it appears that many MPI functions are not supported (MPI_Bsend,etc). If I need this capability then does this mean I should not use boost MPI ? (or is there still a back door way of calling with the C API instead ? ) o Has any one managed to use boost MPI on Super-computers like: - IBM/AIX. - Fujitsu - NEC Since we need to be able swap vendors. Any help appreciated. Ta, Avi

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[unordered] gcc complains in unordered/detail/table.hpp
by Ioannis Papadopoulos 21 Nov '11

21 Nov '11

Hi, In unordered/detail/table.hpp:177 the following exists: iterator& operator++() { node_ = node_ = static_cast<node_pointer>(node_->next_); return *this; } iterator operator++(int) { iterator tmp(node_); node_ = node_ = static_cast<node_pointer>(node_->next_); return tmp; } gcc 4.6.1 complains about boost_1_48_0/include/boost/unordered/detail/table.hpp:177:13: warning: operation on ‘this->boost::unordered::iterator_detail::iterator<boost::unordered::detail::ptr_node<std::pair<const int, int> >*, std::pair<const int, int> >::node_’ may be undefined [-Wsequence-point] what is the purpose of node_ = node_ ?

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