July 2006 - Boost - lists.preview.boost.org

Any interests in a template library for distributed message passing and event dispatching?
by Yigong Liu 25 Sep '06

25 Sep '06

Hello All, Is there any interests in libraries for distributed message passing and event dispatching? There are many aspects involved in the design of these systems, such as choosing proper message/event id types, routing/dispatching algorithms, synchronization strategies for routing data structures and remote connection transport, etc.. Various application domains present different requirements for performance and functionalities (in embedded systems, integers or sub-int (bit-fields) are used as ids and routing is based on registration table, while in the e-commerce applications, class/structs with key attributes can be used as ids to facilitate more advanced routings). I am working on a C++ template library for generic publish/subscribe called Channel. Channel's major components (message IDs, routing algorithms...) are configurable as template parameters. As a namespace shared by peer threads, channels support publish/subscribe scope control, message filtering, and translation. Channel is used the same way as we use STL containers; by instantiating Channel template with proper id type, id trait and routing algorithms, user can create customized message passing and event dispatching facility for a particular application. More documentations and code can be found at : http://channel.sourceforge.net Right now Channel is built on top of ACE (adaptive communication environment) to gain platform independence. Besides classes related to socket connections and message marshaling, most channel classes are quite platform independent. I am refactoring the code and move the platform dependent code into a few policy classes. I would like to know is there any interests in boost for such frameworks. If so, I'll be glad to present a boostified version of the framework for a review process and use existing boost classes for platform abstractions. Thanks Yigong

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TR2 and C++0x heads up
by Beman Dawes 23 Sep '06

23 Sep '06

The C++ standards committee's Library Working Group has proposed a schedule for library changes and extensions: * October 2005: cutoff date for C++0x major library proposals * October 2006: cutoff date for library TR2 proposals * April 2007: cutoff date for C++0x library clean-up papers The usual rule-of-thumb is that new library components go in TR2, while changes to existing components go in C++0x. The LWG will consider exceptions to the rule on a case-by-case basis. The LWG is planning to issue a "Call for Proposals" with details, but in the meantime Boost developers might want to start thinking about which Boost libraries they want to propose to the LWG. Because most proposals go through one or more revisions before being accepted, it helps a proposal's chances if it reaches the committee as many meetings as possible before the final cut-off. So far there are plans to propose Boost.Threads, Boost.Filesystem, and Boost.Signals. As well as proposals for some of the more major libraries, I personally hope someone will do a sweep through Boost looking at some of the smaller utilities and helpers for a possible "Small Additions" proposal. --Beman

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[shared_Ptr] [1.34] URGENT: Outstanding HP-UX / itanium bug
by John Maddock 12 Sep '06

12 Sep '06

Folks we still haven't solved the outstanding issue summarised here: http://lists.boost.org/boost-users/2005/12/15692.php Defining BOOST_SP_USE_PTHREADS is at least a workaround. Should I apply this to Boost.Config or should the sp_counted_base.hpp logic be altered (to keep everything in one place)? Or does anyone believe they have a fix for the assembly code in time for 1.34? Thanks, John.

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[linear algebra] - question to David Abrahams
by Janek Kozicki 01 Sep '06

01 Sep '06

Hello, Not so long ago you have mentioned that you are working on a linear algebra library. I'm very interested in this topic, because I'm using such library in my project. I have looked into the vault but couldn't find this library. Can we have a sneak peek? Questions: 1. will your library provide functions useful when working with small vectors like: cross_product(), dot_product(), normalize() (scale vector so its length()==1), norm() (returns squared length), length(), etc... ? 2. will your library allow Boost.Quaternions to be extended in a way that those two libraries together will be useful for geometrical rotations? 3. will your library provide a way to solve equation Ax=b (A is matrix, b and x are vectors, and x is the unknown). The background for question 2 above: Author of Boost.Quaternions tried to extend the library with code that would allow geomtetrical rotations, but at that time only Boost.Ublas library was available. After some investigation he discovered that matrices and vectors from ublas are unsuitable for the task, and finally he gave up. Following functions would be needed: operator*(vector<3,T1>,quaternion<T2>) // most important from_rotation_matrix(matrix<3,3,T>) to_rotation_matrix() from_axis_angle(vector<3,T1> axis, T2 angle) to_axis_angle() to_euler_angles() and few others. Similar functionality is already in boost vault: directory "Math - Numerics", file Quaternion.h Without quaternion rotations this linear algebra library would be pretty useless for me, so I hope it'll be there :) -- Janek Kozicki |

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boost::scoped_array::release?
by Ralf W. Grosse-Kunstleve 30 Aug '06

30 Aug '06

Does this patch for boost/scoped_array.hpp look useful? < T * release() // never throws < { < T * result = ptr; < ptr = 0; < return result; < } < It allows me to use boost::scoped_array almost like an auto_ptr: int* foo(size) { boost::scoped_array<int> result(new int[size]); // do something to result // if an exception is thrown result will be cleaned up return result.release(); } void bar() { boost::scoped_array<int> foo_result(foo(1000)); // code is still exception safe } I wouldn't need this if - we had std::auto_array (don't think it exists) - std::vector<int>(size) wouldn't do the default construction of all elements and I didn't care about having two pointers instead of just one (sometimes I actually do care) - boost::scoped_array::ptr was protected instead of private so that I could inherit and add release() Are there arguments for not adding release()? Cheers, Ralf __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Boost regression notification (2005-10-26 [RC_1_33_0])
by Douglas Gregor 23 Aug '06

23 Aug '06

Boost regression test failures ------------------------------ Report time: 2005-10-26T14:54:08Z This report lists all regression test failures on release platforms. Detailed report: http://engineering.meta-comm.com/boost-regression/CVS-RC_1_33_0/developer/i… 82 failures in 3 libraries: parameter (1) range (3) serialization (78) |parameter| tutorial: gcc-2.95.3-linux |range| array: vc-6_5 vc-6_5-stlport vc-7_0 |serialization| test_class_info_load_binary_archive: borland-5_6_4 cw-8_3 cw-9_4 cw-9_5-darwin gcc-3_4_3-sunos mingw-3_4_2 vc-6_5 vc-7_0 test_class_info_load_binary_archive_dll: borland-5_6_4 cw-9_4 cw-9_5-darwin gcc-3_4_3-sunos intel-win32-8_1 mingw-3_4_2 vc-6_5 vc-7_0 test_class_info_load_text_archive: borland-5_6_4 cw-8_3 cw-9_4 gcc-3_4_3-sunos mingw-3_4_2 vc-6_5 vc-7_0 test_class_info_load_text_archive_dll: borland-5_6_4 cw-9_4 gcc-3_4_3-sunos intel-win32-8_1 mingw-3_4_2 vc-6_5 vc-7_0 test_class_info_load_text_warchive: borland-5_6_4 cw-8_3 cw-9_4 gcc-3_4_3-sunos vc-7_0 test_class_info_load_text_warchive_dll: borland-5_6_4 cw-9_4 gcc-3_4_3-sunos intel-win32-8_1 vc-7_0 test_class_info_load_xml_archive: borland-5_6_4 cw-8_3 cw-9_4 cw-9_5-darwin gcc-3_4_3-sunos mingw-3_4_2 vc-6_5 vc-7_0 test_class_info_load_xml_archive_dll: borland-5_6_4 cw-9_4 cw-9_5-darwin gcc-3_4_3-sunos intel-win32-8_1 mingw-3_4_2 vc-6_5 vc-7_0 test_class_info_load_xml_warchive: borland-5_6_4 cw-8_3 cw-9_4 gcc-3_4_3-sunos vc-6_5 vc-7_0 test_class_info_load_xml_warchive_dll: borland-5_6_4 cw-9_4 gcc-3_4_3-sunos intel-win32-8_1 vc-6_5 vc-7_0 test_demo_xml_load: borland-5_6_4 gcc-3_4_3-sunos gcc-4_0-darwin intel-win32-8_1 mingw-3_4_2 test_demo_xml_load_dll: borland-5_6_4 gcc-3_4_3-sunos gcc-4_0-darwin mingw-3_4_2 test_shared_ptr_132_text_warchive: intel-win32-8_1

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Boost inspection notifications (RC_1_34_0)
by Rene Rivera 14 Aug '06

14 Aug '06

Boost Inspection Reports An inspection program <http://www.boost.org/tools/inspect/index.html> checks each file in the current Boost CVS for various problems, generating this as output. Problems detected include tabs in files, missing copyrights, broken URL's, and similar misdemeanors. This email is the common top email for the dated daily reports for the Boost 1.34.0 branch (RC_1_34_0). Please see the follow ups for the individual reports. -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org - grafik/redshift-software.com -- 102708583/icq - grafikrobot/aim - grafikrobot/yahoo

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Re: [boost] Exception Visitor
by Ames Andreas 12 Aug '06

12 Aug '06

> -----Original Message----- > From: boost-bounces(a)lists.boost.org > [mailto:boost-bounces@lists.boost.org] On Behalf Of Alexander Nasonov > Sent: Friday, July 28, 2006 12:54 PM > Subject: Re: [boost] Exception Visitor > > Please, NO! > It's my experience that one catch(...) in a program may be a > source of many annoying glitches that users report > periodically but developers don't understand what's going on. > Removing this often helps. Users start reporting crashes. > Most difficult at this stage is to find a user who is able to > run Dr. Watson, check 'Create Crash Dump File' and send a > dump to developers :) > > Also worth noting that SEH is not standard C/C++. FWIW, I'd like to strongly second that. When catching SEH exceptions (like catch(...) does), predictable behaviour is only possible if you compile for 'asynchronous exception handling', which according to the docs increases the generated code size (I don't know about the runtime performance cost). If you compile for 'synchronous exception handling' (the more usual thing, I believe), you should either be prepared to live with bad cleanup of the stack or you install a global SEH-exception handler in each thread you start, which does nothing but rethrow and therefore crash the app. IMHO, that's nothing a library should impose on its apps. Anyway, I fail to see what's the benefit of catching segfaults _as the default behaviour_ (that's not to say there aren't applications that need to do). FWIW again, I won't use a solution which includes catch(...) anytime soon (and esp. not if it's done in a pervasive manner). cheers, aa -- Andreas Ames | Programmer | Comergo GmbH | Voice: +49 69 7505 3213 | ames AT avaya DOT com

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[test] Buglet in floating point comparison code.
by John Maddock 11 Aug '06

11 Aug '06

I'm using Boost.Test, specifically BOOST_CHECK_CLOSE with non-built-in floating point types. In particular I have a type "real_concept" that models the concepts I want an arbitrary real number type to adhere to. This type does *not* specialise std::numeric_limits: deliberately so because I want to support types with whose precision varies at runtime. This causes a problem inside safe_fpt_division which uses std::numeric_limits without the check to see if it's specialised or not. In turn this causes almost all comparisons using real_concept to succeed because safe_fpt_division will almost always return 0 for real_concept. The obvious fix is simply to place the numeric_limits checks inside an if(std::numeric_limits<FPT>::is_specialized) block, and to perform no safety checks in this case and just go ahead and perform the division regardless (there are no checks that can be performed in this case anyway). Thanks, John.

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[utility] nonconstructible
by Chris Weed 11 Aug '06

11 Aug '06

Hi, I think it would be nice to have a "nonconstructible" class to derive from similar to noncopyable. Recently I was burned by a traits class that was getting constructed. I think this should also be used for template metafunctions. I envision something like the following: struct nonconstructible { private: nonconstructible() {} } template<typename T> struct my_traits : nonconstructible { typedef int my_type; }; Chris

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