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Boost.Log: Set formatter for named_scope attr.
by David Puffer 14 Nov '13

14 Nov '13

Hi, Being new to Boost.Log (and Boost in general) I have spent the last few days trying to implement Boost.Log - which Is working fairly well by now. However - I encountered one problem that I've not been able to solve by now, although it seems to me quite trivial: I have successfully registered the "named_scope" attribute and I am populating its value by a call to BOOST_LOG_FUNCTION. This works well and I can see the function-name in my log-output. However - I also want the line-number and the file-name, and discovered that there's a possibility to set the output-format of the "named_scope" attribute (which already incorporates file-name and line-number info) like so: #include <boost/log/expressions/formatters/named_scope.hpp> sink->set_formatter(expr::stream << expr::format_named_scope("Scopes", "%n")); As documented here: http://www.boost.org/doc/libs/1_54_0/libs/log/doc/html/log/detailed/express… I just don't seem to find any way to get to my sink - which is configured in a settings-file and evaluated by a call to the init_from_stream() function. Is there any way to query for all the sinks - or get a sink by name? How is one supposed to set a sink formatter for a sink which was generated by the library and not the user? Or is there a way to specify the output-format for named attributes via a settings-file as well? As far as I can see it's only possible to format the output of a log record as a whole - but not single attributes. Also: Is it correct, that the above function will only set the format for the "Scopes" attribute - which means I could call this function repeatedly for lets say the "TimeStamp" attribute as well? Best regards, David

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[Log] Error with operator<< in basic_formatting_ostream
by Víctor Yo 14 Nov '13

14 Nov '13

Hi ewveryone, I'm working lately with Boost.Log (I'm a newbie) library and I want to write a logger with some parameters and formatting options. I followed the documentation, I created a backend and a frontend and I tried to format the output in the frontend with the set_formatter() function. I tried with the Lambda style and with the Boost.Format style but I'm getting an error that I can not locate. Iwas working on it for the last two whole days but I couldn't find a solution. It is related with the basic_formatting_ostream, but I don't understand what that means. I defined the backend and attached to it two streams (to a file and to cout) typedef boost::log::sinks::text_ostream_backend our_backend; typedef boost::log::sinks::synchronous_sink<our_backend> our_frontend; //............................................................................................................................................ boost::shared_ptr<our_backend> backend = boost::make_shared<our_backend>(); //Stream definitions boost::shared_ptr<std::ostream> stream_out(&std::cout, boost::log::empty_deleter()); boost::shared_ptr<std::ostream> stream_file(new std::ofstream("file_logger.log")); backend -> add_stream(stream_out); backend -> add_stream(stream_file); Created the frontend (and wrapping the backend to it) //Wrap the backend into the frontend and register in the core. //The frontend provides synchronization for the backend. boost::shared_ptr<our_frontend> frontend(new our_frontend(backend)); And now come the offending code which is supposed to format the output (note that the first commented block was my first try). None of them works and the error is the same in both cases: */*frontend -> set_formatter* * (* * boost::log::expressions::format("[%1%] %2%, File: %3%, Line: %4% <%5%>: %6% ")* * % boost::log::attributes::counter< unsigned int >(1)* * % boost::log::attributes::local_clock()* * % boost::log::expressions::attr< severity_level >("Severity")* * % boost::log::expressions::message* * );*/* //We are going to define the formatter in a different style to try to get formatted output frontend -> set_formatter ( boost::log::expressions::stream << boost::log::attributes::counter< unsigned int >(1) <<" ["<< boost::log::attributes::local_clock() <<"] <"<< boost::log::expressions::attr< severity_level >("Severity") <<"> "<< boost::log::expressions::message ); The error I get is the next one: */home/victor/Programacion/workspace/opice/build-parallel/../libs/include/boost/log/utility/formatting_ostream.hpp:664:5: error: no match for ‘operator<<’ in ‘(& strm)->boost::log::v2_mt_posix::basic_formatting_ostream<CharT, TraitsT, AllocatorT>::stream [with CharT = char, TraitsT = std::char_traits<char>, AllocatorT = std::allocator<char>, boost::log::v2_mt_posix::basic_formatting_ostream<CharT, TraitsT, AllocatorT>::ostream_type = std::basic_ostream<char>]() << value’* And I really don't know what is happening. I also included a lot of files (I'm sure I included too much files, indeed) to be sure it was not caused by some undefined operator or something similar. However I still have the same problem. The includes are: #include <iostream> #include <fstream> #include <string> #include <boost/thread/shared_mutex.hpp> #include <boost/log/core.hpp> #include <boost/log/common.hpp> #include <boost/make_shared.hpp> #include <boost/log/expressions.hpp> #include <boost/log/utility/setup/file.hpp> #include <boost/log/utility/setup/console.hpp> //puede ser innecesario #include <boost/log/utility/setup/common_attributes.hpp> //puede ser innecesario #include <boost/log/utility/empty_deleter.hpp> #include<boost/thread/mutex.hpp> #include <boost/log/attributes/timer.hpp> #include <boost/log/attributes/mutable_constant.hpp> #include <boost/log/sources/severity_logger.hpp> #include <boost/log/utility/formatting_ostream.hpp> #include <boost/log/sinks/text_ostream_backend.hpp> #include <boost/log/sinks/sync_frontend.hpp> #include <boost/log/support/date_time.hpp> As you can see, they are probably redundant or innecessary but I could rip off that files when I could get the program compiled. Now, I'm out of ideas so any help you could bring me should be very appreciated. Thank you in advance. Victor Hevia

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[1.55] PDF Documentation build available.
by John Maddock 14 Nov '13

14 Nov '13

The final PDF documentation build for Boost-1.55 is now available at https://sourceforge.net/projects/boost/files/boost-docs/1.55.0/ As ever this only contains documentation for the subset of Boost libraries that use quickbook/boostbook/docbook based documentation. Enjoy! John.

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Boost 1.54.0 Header Warnings: Shadowed Variables
by Tom Browder 13 Nov '13

13 Nov '13

I am trying to use Boost 1.54.0 to replace a previous version (1.47) and am using g++ 4.7 with most warnings turned on. I am getting many -Wshadow errors and wonder why they exist. Surely the developers test for such. Here is one example from xpressive/detail/utility/hash_peek_bitset.hpp: Both 'icase' and 'count' are reported to shadow members of 'this'. Note that the bool arg is named 'icase' but the compiler reports 'this' has a member named 'icase' (as can be plainly seen below). In this example it's fairly clear what is intended, but then again maybe not (and it doesn't give the user much confidence in the code). It isn't good practice IMHO to do such so that is why I like to use some prefix or suffix to disambiguate the two variables. // Make sure all sub-expressions being merged have the same case-sensitivity bool test_icase_(bool icase) { std::size_t count = this->bset_.count(); if(256 == count) { return false; // all set already, nothing to do } else if(0 != count && this->icase_ != icase) { this->set_all(); // icase mismatch! set all and bail return false; } this->icase_ = icase; return true; } I could file many bugs but it begs the question of why the warnings are allowed in the first place. Suggestions? Thanks and best regards, -Tom

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[Boost.Iterator] Problem compiling zip_iterator with clang and C++11
by Jonathan Jones 13 Nov '13

13 Nov '13

Hi folks, The following code fails to compile on OSX 10.8.5 with Xcode 5.0.1 and Boost 1.49.0. This is not real world code, but it demonstrates the problem I'm facing. #include <boost/iterator/zip_iterator.hpp> template<typename T> void foo() { boost::zip_iterator<boost::tuple<T*, T*> > iter; std::fill(iter, iter, std::make_pair(T(),T())); } void bar() { foo<int>(); } Here are the commands I used to compile (if I drop "-stdlib=libc++" from the compile line, the code compiles just fine): setenv DEVELOPER_DIR /Applications/Xcode5.0.1.app/Contents/Developer xcrun -sdk macosx10.8 clang++ -c zip_iterator.cpp -I<boost-path>/include -std=c++11 -stdlib=libc++ and here is a heavily formatted snippet of the key error: /Applications/Xcode5.0.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/c++/v1/algorithm:1824:1: note: candidate function [with _RandomAccessIterator = boost::zip_iterator<boost::tuples::tuple<int*, int*>>, _Tp = std::__1::pair<int, int>] not viable: no known conversion from typename iterator_traits<zip_iterator<tuple<int*, int*>>>::iterator_category (aka 'boost::detail::iterator_category_with_traversal<std::__1::input_iterator_tag, boost::random_access_traversal_tag>') to 'std::__1::random_access_iterator_tag' for 4th argument __fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value_, random_access_iterator_tag) Any help is appreciated. Thanks, Jon

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[Math] BOOST_FPU_EXCEPTION_GUARD on Linux
by David Roberts 13 Nov '13

13 Nov '13

Hello, I have a program that makes considerable use of the gamma distribution from Boost.Math. Profiling with OProfile has shown that, on Linux, this program spends about 20% of its runtime calling the functions fesetexceptflag() and feclearexcept(). The code responsible for calling these is in the BOOST_FPU_EXCEPTION_GUARD macro which is defined in boost/math/tools/config.hpp. I have looked back through the source history to see when and why this macro was added, and it was in changeset 3186 from September 2006 with the comment "More linux fixes: finally got AMD64 machines to behave correctly" (see https://svn.boost.org/trac/boost/changeset/3186) In Boost 1.54 the conditions under which the guard macro is defined have been refined since it was originally added, but the guard class itself remains the same as in 2006. Given the performance penalty I am suffering as a result of constantly clearing and reseting the floating point exception flags, I have a couple of questions about this functionality: 1) Can anyone provide a specific test case that did not work without the BOOST_FPU_EXCEPTION_GUARD functionality but was fixed by its addition? It would be very useful to have such a test case because then I can check if this is still a problem on recent versions of Linux. 2) The commit comment for changeset 3186 refers to AMD64. Does this mean the original problem only occurred on AMD CPUs, or does this refer to the architecture, and hence it affected both Intel and AMD CPUs? Many thanks, David Roberts

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[Graph] Static allocation of nodes and edges
by Sensei 13 Nov '13

13 Nov '13

Dear all, I need to optimize my code with regards to both memory and time. The problem is simple: pre-allocating the adjacency matrix. The graph may have a huge number of nodes N, but the number of edges K per node is limited. While N can be in the order of one hundred million, K is at most 10. The graph will be directed, so no symmetry is needed. Do you know if I can pre-allocate such an adjacency matrix? If not, I suppose I must use an adjacency list in order to minimize memory consumption, am I right? Thanks!

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Help with lockfree queue
by TYSON Kieran 13 Nov '13

13 Nov '13

[@@ OPEN @@] Hello, I am using a global lockfree queue to transfer a message from different threads. The program compiles and runs without fault up until the program exits and the queues destructor is called. An unhandled exception is thrown on the destruction of the queue. Below is the code used to set up the queue. #define B1_OUTPUT_LENGTH_PER_CHANNEL (32000) #define B2_OUTPUT_LENGTH_PER_CHANNEL (32000) #define B3_OUTPUT_LENGTH_PER_CHANNEL (64000) #define NB_CHANNELS (8) typedef struct s_OutputMsg { float dataB1[(int)B1_OUTPUT_LENGTH_PER_CHANNEL*NB_CHANNELS]; float dataB2[(int)B2_OUTPUT_LENGTH_PER_CHANNEL*NB_CHANNELS]; float dataB3[(int)B3_OUTPUT_LENGTH_PER_CHANNEL*NB_CHANNELS]; int dataLength; } OutputMsg; boost::lockfree::queue<OutputMsg, boost::lockfree::fixed_sized<true>> dataMsgQueue(100); My first thoughts are that there are limitations on the size of the message because I have used simple integer queues in the past with no problem. Are there size limitations on the message of a lockfree queue? Thanks, Kieran This message contains OPEN information that is not sensitive and can be freely accessed by people both inside and outside of the Thales Group This email was classified by Tyson, Kieran on Wednesday, 13 November 2013 10:58:41 AM ------------------------------------------------------------------------- DISCLAIMER: This e-mail transmission and any documents, files and previous e-mail messages attached to it are private and confidential. They may contain proprietary or copyright material or information that is subject to legal professional privilege. They are for the use of the intended recipient only. Any unauthorised viewing, use, disclosure, copying, alteration, storage or distribution of, or reliance on, this message is strictly prohibited. No part may be reproduced, adapted or transmitted without the written permission of the owner. If you have received this transmission in error, or are not an authorised recipient, please immediately notify the sender by return email, delete this message and all copies from your e-mail system, and destroy any printed copies. Receipt by anyone other than the intended recipient should not be deemed a waiver of any privilege or protection. Thales Australia does not warrant or represent that this e-mail or any documents, files and previous e-mail messages attached are error or virus free. -------------------------------------------------------------------------

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How to convert cmyk jpg file to rgb jpg file with BOOST.GIL?
by Guangchao Wang 13 Nov '13

13 Nov '13

I used following code: rgb8_image_t rgb8Img; jpeg_read_and_convert_image("CMYK.jpg", rgb8Img); //CMYK.jpg is CMYK image jpeg_write_view("RGB.jpg", const_view(rgb8Img)); to convert CMYK image to RGB image. The saved RGB.jpg is not correct. Could you give me some suggestion? Thanks.

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[Locale] Getting correct system locale under Mac OS X
by Orhun Birsoy 11 Nov '13

11 Nov '13

I am using boost 1.55.0.rc2. I am running 10.8.5 and when I select "Norway (Norwegian Bokmal)" (nb_NO) as the region, LANG env. variable is undefined, making boost::locale::generator("") to generate a "C" locale. I can of-course get the locale identifier from NSLocale (or CFLocale) and initialize the boost::locale::generator with "nb_NO" which seems to be working, but with Mavericks things got even more interesting. It looks like, in 10.9 you can mix and match language with a country anyway you like i.e. I can select "Norway" as my region and "English" as my language and again LANG is empty but NSLocale returns "en_NO". But this time when I use boost::locale::generator("en_NO"), boost::locale::as::number uses "." (dot) as decimal separator, although NSLocale reports "," (comma). 1. Can boost::locale handle such combinations (en_NO, en_TR, etc)? (I am using ICU backend, others are explicitly turned off). a. for number formatting? b. for messages formatting (translations)? which mo will it pick for en_TR ? 2. How can I 'customize' locale generated by boost::locale to reflect the changes user might do in system locale settings (i.e. select en_US but change the decimal symbol)? Thanks. -- Orhun Birsoy

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