July 2011 - Boost-users - lists.preview.boost.org

Boost.Iterator and future standards?
by John M. Dlugosz 19 Jul '11

19 Jul '11

The documentation for Boost.Iterator says "Both iterator_facade and iterator_adaptor as well as many of the specialized adaptors <http://www.boost.org/doc/libs/1_46_1/libs/iterator/doc/index.html#specializ…> mentioned below have been proposed for standardization, and accepted into the first C++ technical report" But I don't see that in <http://www.boost.org/doc/libs/1_46_1/doc/html/boost_tr1.html> or notice anything concerning them in other TR1 writeups. Can someone clarify the situation?

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[icl] possible bug for set difference
by Thomas Taylor 18 Jul '11

18 Jul '11

Hi! First let me express my happiness for having this library, as it makes a lot of my programming tasks much easier! While using it I think I discovered a bug for interval_set, when a difference is calculated; please find a test case attached. This was compiled against recent svn (r73190). cheers, Thomas

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Boost.Log
by asif saeed 18 Jul '11

18 Jul '11

Hi, What is the status of Boost.Log? Is operating system log (e.g. Windows Event Log, Unix's Syslog) supported? If logging via OS is not supported then how it can be implemented, would you please give me a link or some examples/guidelines? Best, Asif

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[Rational] "r.den > zero" assertion failure
by Pierre Cagne 18 Jul '11

18 Jul '11

Hi, I'm having a weird dynamic failure using Boost.Rational. Using some rationals and doing a calculus, i'm ending with a rational with a negative denominator, and so unusable for comparison (hence the r.den > 0 assertion failure during the execution). More precisely, here is a piece of code : (with typedef boost::rational<mpz_class> rat) std::cout << xa << " " << ya << " " << xb << " " << yb << " " << xc << " " << yc << " " << xd << " " << yd << std::endl; // determinant rat delta = (xb - xa)*(yc - yd) - (yb - ya)*(xc - xd); std::cout << "Delta : " << delta << std::endl; /* ... some comparisons on delta ...*/ For the following result : 0/1 1/4 1/2 0/1 0/1 0/1 1/1 0/1 Delta : 1/-4 Assertion failed: (r.den > zero), function operator<, file /usr/local/include/boost/rational.hpp, line 388. How does it come that Boost does not maintain the assertion correct ? I precise that the same code with the type boost::rational<int> does not produce the failure. Thankfully. P.S. : i'm new on this mailing-list ; does my message match with the common pattern of this list ? -- Pierre Cagne pierre.cagne(a)gmail.com

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in the makefile, how to find/configure boost lib path and include path on different machines?
by deqiang sun 17 Jul '11

17 Jul '11

Hi all, I am writing a small program depending on boost libs. However, my work environment unfortunately includes many computers with boost installed on different locations. In such scenario, how should I write the makefile to make it correctly include headers and link to libs? Thanks very much, DSUN

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exception problem with boost::filesystem under cygwin
by Kraus Philipp 17 Jul '11

17 Jul '11

Hello, I'm using boost::filesystem within my project (boost 1.47.0). I have compiled the boost under cygwin with bjam. I have some problems with exception throws / catches: The following example shows the problem: #include <stdexcept> #include <boost/filesystem.hpp> int main(int argc, char* argv[]) { throw std::runtime_error("xxx"); return 0; } If I compile this code under Cygwin and link cygboost_filesystem and cygboost_system, the programs terminates with this messages: terminate called after throwing an instance of 'std::runtime_error' terminate called recursively If I remove the boost/filesystem include the program produce the correct message: terminate called after throwing an instance of 'std::runtime_error' what(): xxx If I change the program to: int main(int argc, char* argv[]) { try { throw std::runtime_error("xxx"); } catch (...) {} return 0; } the program breaks down with the filesystem include: terminate called after throwing an instance of 'std::runtime_error' terminate called recursively without the include always works fine. Can anyone help me to solve the problem? Thanks a lot Phil

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[fusion] BOOST_FUSION_DEFINE_STRUCT at class scope
by Nathan Ridge 17 Jul '11

17 Jul '11

Hello, The documentation of BOOST_FUSION_DEFINE_STRUCT says it should be used at global scope. Why can't this function be used at namespace scope, and, especially, at class scope? Not being able to use it at namespace scope is just as annoyance because it means the current namespace(s) have to be closed before the macro and re-opened after it; but not being able to use it at class scope means that it cannot be used to declare nested structures which are fusion sequences at all. Is there another device that allows us to declare nested structure that are fusion sequences? Thanks, Nate.

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[Review] Type Traits Introspection library by Edward Diener starts tomorrow Friday 1
by Joel Falcou 17 Jul '11

17 Jul '11

According to the schedule, review for the Type Traits Introspection library by Edward Diener starts this friday and run till July 10th. =========== What is it? =========== The TTI library, which is an abbreviation for the 'Type Traits Introspection' library, allows a programmer to introspect at compile time the inner elements of a C++ type. The introspection process depends on specifying the name of the inner element by different macros for different types of elements, and then using a generated metafunction to determine whether that element exists within the enclosing type. The inner elements which can be introspected are type, class template, member data, member function, static member data, and static member function. The TTI library is based on the type_traits_ext portion of the Concept Traits Library, with improvements and additions, and also reproduces functionality ( without changing existing code ), for the purposes of completeness, from Boost.MPL regarding introspection of types and templates. The purpose of the library is to provide a consistent set of interfaces for doing compile-time introspection of a type, which other template metaprogrammers can use in their code. If you are at all interested in compile-time introspection of types, please take a look at the functionality of this library. =================== Getting the library =================== The library is available at http://svn.boost.org/svn/boost/sandbox/tti/ Note that this repository will be updated up to next thursday by Edward. =================== Writing a Review =================== The reviews and all comments should be submitted to the developers list, and the email should have "[TTI] Review" at the beginning of the subject line to make sure it's not missed. Please explicitly state in your review whether the library should be accepted. The general review checklist: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? And finally, every review should answer this question: - Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion.

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[serialization] writing private variables
by Sean Farrow 16 Jul '11

16 Jul '11

Hi: Is there a way to tell the serialization library to write private members. The members do have functions to get/set there values, but as far I know the serialization subsystem doesn't call these. Cheers Sean.

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[Pool] Attention all Pool users....
by John Maddock 16 Jul '11

16 Jul '11

Folks, I'm planning on merging the all new and shiny version of Boost.Pool in the sandbox under https://svn.boost.org/svn/boost/sandbox/guild/pool/ into Trunk pretty soon unless anyone objects. There are a lot of bug fixes in this version, plus updated docs (see https://svn.boost.org/svn/boost/sandbox/guild/pool/libs/pool/doc/pool.pdf). Please let me know if you spot any issues, or if there's something that needs addressing that hasn't been (no promises on that one though!). Regards, John.

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