June 2009 - Boost - lists.preview.boost.org

Boost.logging bugs
by Dmitriy Lyfar 06 Jun '09

06 Jun '09

Hello, We are using boost.logging library in our project. We prefered that library because of header-only structure and it looks great. But recently I have found some two bugs. First of them its crash while output in syslog. I found that template<class msg_type> void operator()(const msg_type & msg) const { syslog( LOG_INFO, msg.c_str() ); } looks incorrect, because second argument is format string, so next line lead boost.logging to crash: amazon.co.uk%2fgp%2f%26nbsp%3b%2fref%3dpe_15031_15751501_pe_47%2f%26nbsp%3b (I need output some html parts in syslog like debug info). So I replaced code above with: template<class msg_type> void operator()(const msg_type & msg) const { syslog( LOG_INFO, "%s", msg.c_str() ); } Which works correct, but it seems not general solution. What do you think? And the second one is compiling under gcc 3.4.6 issue: ../3rdparty/boost/boost_1_37_0/boost/logging/format/destination/syslog.hpp: In member function `void boost::logging::destination::syslog_no_levels_t<convert_dest>::operator()(const msg_type&) const [with msg_type = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, convert_dest = boost::logging::destination::do_convert_destination]': ../3rdparty/boost/boost_1_37_0/boost/logging/detail/manipulator.hpp:571: instantiated from `void boost::logging::manipulator::detail::generic_holder<generic_type, manipulator_base>::operator()(typename manipulator_base::param) const [with generic_type = boost::logging::destination::syslog_no_levels_t<boost::logging::destination::do_convert_destination>, manipulator_base = boost::logging::destination::base<boost::logging::default_, boost::logging::default_>]' LMLog.cpp:219: instantiated from here ../3rdparty/boost/boost_1_37_0/boost/logging/format/destination/syslog.hpp:41: error: expected primary-expression That can be fixed by pointing template keyword before operator() calling: ../3rdparty/boost/boost_1_37_0/boost/logging/detail/manipulator.hpp:571 Use virtual void operator()(param val) const { m_val.template operator()(val); } Instead virtual void operator()(param val) const { m_val.operator()(val); } Thank you for such library, I'm waiting for your comments. Regards, Dmitriy Lyfar.

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Forwarded Message: Re: Bug Sprint - #1777 provide md5
by Kasra 06 Jun '09

06 Jun '09

Hi, I an Kevin Sopp are working on boost::crypto which will have an implementation of md5 and many other algorithms. The library is scheduled to be finished before Xmas. With Best Regards Mr. Kasra Nassiri Department of Mathematics & Computer Science Imperial College London

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Interest check: Boost.Debug
by Zachary Turner 06 Jun '09

06 Jun '09

In my spare time I have been working on a library to analyze debug information from a running program. It either already does, or I would like to have it before I'm done, support all of the following (I'm sure there are plenty of other neat additions that I haven't thought of): - Loading debug info either for the currently running executable or from an offline executable - Printing human readable stack traces from a running program - Dumping stack traces to a file in release mode. In this case it's usually just a dump of the entire stack in binary. - Matching dumped stacks from step 3 to debug information offline to get post-mortem information. - Assuming symbol information is loaded either for the running program or an offline program, format a block of memory in a human readable format to print the structure of the memory (for example, display member values of a class with field names, given a block of memory representing an instance of the class) - Iteration of loaded modules - Check whether debugger is attached - output stream that goes to the debugger console, and is not visible in the debugged process. I'm not sure about the feasibility under non-windows platforms (it's very easy in windows), but I would think that if it's possible to figure out the PID of the process debugging you, that it should be possible to send output to their stderr which should achieve the same effect. - launch process under a debugger and receive basic types of debugging notifications. There's some obvious portability concerns, and some of these things are (considerably) more difficult than others, so I can't say I'd be able to support everything. However I already have rudimentary support for about half the items on the list although it is definitely in its infancy since before now I had not considered extending this to any other platforms / architectures. Main problem is that I can't say that I know enough about OSes other than Windows, and architectures other than x86/x64 to know if it would be not worth the hassle to prepare something like this for introduction into boost. Also everything I've done so far is only on Windows, and I don't suppose I'd have the know-how to make it work on any other OS, so in that sense I'd need some assistance. That being said, is it worth it to tackle something like this or should I just not worry about the generality and keep working on it for personal use only?

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[spirit]
by Chandrashekhar Kumar 06 Jun '09

06 Jun '09

Hi, I have to parse the file, the contents of which(with a header) is below and stuff the double part only to std::vector<double>: "A","B","C","D" 1,2,3,4 5,6.7,8 ........ I started simple without header approach first : from libs/spirit/example/lex/example.hpp: inline std::string read_from_file(char const* infile) { std::ifstream instream(infile); if (!instream.is_open()) { std::cerr << "Couldn't open file: " << infile << std::endl; exit(-1); } instream.unsetf(std::ios::skipws); // No white space skipping! return std::string(std::istreambuf_iterator<char>(instream.rdbuf()), std::istreambuf_iterator<char>()); } from libs/spirit/classic/examples/number_list.hpp: /////////////////////////////////////////////////////////////////////////////// // // Our comma separated list parser // /////////////////////////////////////////////////////////////////////////////// bool parse_numbers(char const* str, vector<double>& v) { return parse(str, // Begin grammar ( real_p[push_back_a(v)] >> *(',' >> real_p[push_back_a(v)]) ) , // End grammar space_p).full; } int main() { std::string str = read_from_file("test.csv"); std::vector<double> v; if (parse_numbers(str.c_str(), v)) { cout << "-------------------------\n"; cout << "Parsing succeeded\n"; cout << str << " Parses OK: " << endl; for (vector<double>::size_type i = 0; i < v.size(); ++i) cout << i << ": " << v[i] << endl; cout << "-------------------------\n"; } else { cout << "-------------------------\n"; cout << "Parsing failed\n"; cout << "-------------------------\n"; } } But after running it, I am getting the result as "Parsing failed". I am going thru the doc to understand it better, but any quick spot will help me immensely. Thanks, Chandra

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[Bug Sprint] Ticket #351
by Marshall Clow 05 Jun '09

05 Jun '09

https://svn.boost.org/trac/boost/ticket/351 is the oldest "bug" in the trac system. I'm trying to figure out what Jens meant in his last comment (dated 4-11-2005), where he said "See issue 4.40 in the C++ committee's library TR issue list". I looked at the current version of the library issues list <http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html>, and they don't have a 4.40 :-( I looked at revision #33 of this document (from April 2005), and they didn't have a 4.40 either. Anyone know what document he was referring to? -- -- Marshall Marshall Clow Idio Software <mailto:marshall@idio.com> It is by caffeine alone I set my mind in motion. It is by the beans of Java that thoughts acquire speed, the hands acquire shaking, the shaking becomes a warning. It is by caffeine alone I set my mind in motion.

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Bug Sprint Report for Thursday, June 4th
by Marshall Clow 05 Jun '09

05 Jun '09

The boost bug sprint started Friday, May 29th, and runs through Sunday June 7th. Thursday was a very good day - let's keep it up! The bug sprint will be over Sunday night. Status <https://svn.boost.org/trac/boost/report/1> 7:00 AM PDT 5/29: 797 open tickets. 7:45 AM PDT 5/30: 772 open tickets. 6:00 AM PDT 5/31: 761 open tickets. 6:00 AM PDT 6/2: 747 open tickets. 6:00 AM PDT 6/3: 748 open tickets. 6:00 AM PDT 6/4: 739 open tickets. 8:00 AM PDT 6/5: 730 open tickets. Activity: 5/29: 6 new tickets, 77 modifications, 25 tickets closed 5/30: 2 new tickets, 42 modifications, 17 tickets closed 5/31: 2 new tickets, 27 modifications, 8 tickets closed 6/1: 2 new tickets, 42 modifications, 17 tickets closed 6/2: 5 new tickets, 18 modifications, 5 tickets closed. 6/3: 4 new tickets, 19 modifications, 2 tickets closed. 6/4: 3 new tickets, 42 modifications, 24 tickets closed. [ Numbers may not add up because I am counting via two different methods, using data that is time-stamped in two different time zones. Also, tickets can be closed and reopened. ] What can you do? See <https://svn.boost.org/trac/boost/wiki/BugSprintJune2009> for details. I've added four new reports to the trac: Open ticket count by owner: <https://svn.boost.org/trac/boost/report/18> Open ticket count by component: <https://svn.boost.org/trac/boost/report/19> Open ticket count by ticket type: <https://svn.boost.org/trac/boost/report/20> Open ticket count by milestone: <https://svn.boost.org/trac/boost/report/21> There's been a lot of discussion on the list about tickets; and there are about a dozen patches that have been tested and are ready to be applied. If you're looking to help, you can look at some of the older bugs, say, the ones for Boost 1.36, and determine if they still apply. If they do, note that in the ticket. There are 35 tickets that are still open that are marked as "to be fixed in Boost 1.36" See <https://svn.boost.org/trac/boost/report/3> for a list of open tickets by milestone. --------- Sign-up sheet -------- The following people have committed to participate in the bug sprint. Please add you name here, along with what you can do. 1) Marshall Clow (coordination, Mac OS X characterization) 2) Beman Dawes (filesystem, system, timer) 3) Doug Gregor (function, graph, logic, mpi, numeric, property_map, signals) 4) "joel falcou" <joel.falcou(a)u-psud.fr> ( linux gcc testing/VC 2008 testing, patching) 5) Michael Caisse <boost(a)objectmodelingdesigns.com> (bug fixing) 6) Jeremiah Willcock <jewillco(a)osl.iu.edu> (will test and commit graph patches) 7) David Abrahams (iterator, python) 8) Sohail Somani (patches for g++ 4.2.4) 9) Steven Watanabe <watanabesj(a)gmail.com> (bug fixes, como) 10) vicente.botet" <vicente.botet(a)wanadoo.fr> 11) Stjepan Rajko <stjepan.rajko(a)gmail.com> (fusion) 12) Daniel Wallin (parameter, ...) -- -- Marshall Marshall Clow Idio Software <mailto:marshall@idio.com> It is by caffeine alone I set my mind in motion. It is by the beans of Java that thoughts acquire speed, the hands acquire shaking, the shaking becomes a warning. It is by caffeine alone I set my mind in motion.

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[iterator] std::sort on zip_iterator (repost)
by Jeremiah Willcock 05 Jun '09

05 Jun '09

(Resubmitting to Boost list because I did not receive any answers on boost-users, nor any helpful answers on the Boost list.) I would like to sort two separate vectors of numbers, treating corresponding elements of the two vectors as tuples and sorting the tuples. In particular, I am only comparing the first elements of the tuples; that may or may not be relevant to my problem. An example program is: #include <vector> #include <algorithm> #include <iostream> #include <boost/tuple/tuple.hpp> #include <boost/iterator/zip_iterator.hpp> struct compare_first_elements_in_tuples { template <typename Tuple> bool operator()(const Tuple& a, const Tuple& b) const { return (a.template get<0>()) < (b.template get<0>()); } }; int main(int, char**) { size_t a_data[5] = {0, 2, 1, 2, 4}; size_t b_data[5] = {1, 1, 5, 3, 7}; std::vector<size_t> a(a_data, a_data + 5); std::vector<size_t> b(b_data, b_data + 5); std::cout << "Before:"; for (size_t i = 0; i < a.size(); ++i) { std::cout << " (" << a[i] << ", " << b[i] << ")"; } std::cout << std::endl; typedef std::vector<size_t>::iterator vec_iter; typedef boost::zip_iterator<boost::tuple<vec_iter, vec_iter> > zip_iter; std::sort(zip_iter(boost::make_tuple(a.begin(), b.begin())), zip_iter(boost::make_tuple(a.end(), b.end())), compare_first_elements_in_tuples()); std::cout << "After:"; for (size_t i = 0; i < a.size(); ++i) { std::cout << " (" << a[i] << ", " << b[i] << ")"; } std::cout << std::endl; return 0; } On gcc 4.0.1, the sort operation results in the element (2, 1) (a pair of corresponding elements in a and b) being duplicated, while the element (1, 5) does not appear in the result at all: Before: (0, 1) (2, 1) (1, 5) (2, 3) (4, 7) After: (0, 1) (2, 1) (2, 1) (2, 3) (4, 7) I suspect the problem is related to the fact that zip_iterator does not return a "real" reference when dereferenced. Am I mistaken about this? Is the code above supposed to work? If not, is there an alternative way to sort one sequence while swapping elements in another in a corresponding way? I am not able to join the two input sequences into a single sequence of pairs because of other factors in the use case for this code. Thank you for your help. -- Jeremiah Willcock

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[Bug Sprint] [variant] #2839 ambiguous swap call
by Daniel Hulme 05 Jun '09

05 Jun '09

I've just added a test program to ticket #2839: it fails on vc9. The ticket, I think, explains the problem pretty well, but I would like an expert to look at the code. I believe that the program is ill-formed, and it only works on gcc because the BOOST_WORKAROUND disables the code in question. The issue is that variant/detail/move.hpp:114 introduces a templated swap() overload in the same scope it will be called from, to allow move emulation. But, if the variant bounds a type defined in std::, like std::vector, then std::swap is another templated swap() and will be found by ADL. This makes the call ambiguous. My recommendation is that the move-emulation code be removed -- or enable_if'd, if that's possible -- until the generalised Boost.Move implementation is ready to be adopted. If we believe the code as it stands is correct, then I think the test case should be added to trunk and release, and additional BOOST_WORKAROUNDs added for all the compilers where the test fails. -- “Papa Hegel he say that all we learn from history is that we learn noth- hing from history. I know people who can't even learn from what happened this morning. Hegel must have been taking the long view.” -- John Brunner, ‘Stand on Zanzibar’

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Re: [boost] boost.timer library submission...
by JohnQ 05 Jun '09

05 Jun '09

Hi Dmitry, Answers in-line... >> Do you hold a mutex locked while invoking a callback? yes, I'm holding a boost::unique_lock<boost::mutex>... as a result, the callback method shouldn't do much. Mine only records the fact that the timer fired and the data passed back and puts it on a queue for another of my app threads to handle. >>What mechanism do you use to suspend till it's time to fire a callback? boost::condition_variable m_timed_cond.timed_wait(timer_lock, cur_timer) >>What is the precision of your library? I mean if you instruct the >>library to invoke your callback in so many ms usually your callback will >>be invoked at bit later. The question is how long later? Or earlier? Typically fires later than earlier... the tolerance window I've been using is 5 ms - 10ms. The unit test included in the lib I uploaded to boost value includes a test that puts 100 timers up and measures when they fire. Occassionally out of that window. So far I've been running this on my mac and there's a lot running on it typically, so I'm suspicious of my results and think they could be better. >>Does the precision degrade when you register lots of callbacks? Not that I know of... I've put a couple of hundred thousand in there... so far the time to rebalance the underlying map for insertion / deletion hasn't shown up as an effect. >>What's the smallest possible timeout the library lets to register a >>callback with? How does the library handle small (e.g. 1 ms) timeout >>requests? Currently, millisecond resolution but totally happy to change it to reflect the greatest accuracy the underlying system timer can achieve. I've been testing this with a timing window (i.e., anything within, say, 10ms of the original timer also gets called back). The timing window is configurable. What platforms does the library work on? Been compiling this on my mac. Will have it running on Centos shortly. Haven't tried it at all on Win platform yet. >>BR, Dmitry Thanks, John Q.

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Re: [boost] sorting library proposal
by Steven Ross 05 Jun '09

05 Jun '09

Is there a good way to issue a compile-time warning telling people that integer_sort or float_sort isn't being used, because they passed in an incompatible data type? I see static assertions, but what I need is an equivalent static warning, after which I use std::sort. integer_sort won't run on long longs, because it uses size_t for distance codes. I've added a check to see whether the key type being used is of the same size or smaller than a size_t to handle this problem. I don't think integer_sort is an appropriate algorithm for data types larger than a size_t, unless comparisons are ridiculously slow, as the k/s factor starts becoming quite large. Also, I'm using a simple if to decided this: if(sizeof(Div_type) <= sizeof(size_t)) because enable_if appears to only work with classes. I'm assuming here that the compiler is smart enough to figure out that the expression is constant and to only bring in the code if it's true. It would be nice to be able to eliminate the compiler warnings about size, and issue a more concise and meaningful message telling the user that their data type is too big for integer_sort (or incompatible with float_sort, as appropriate).

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