December 2008 - Boost - lists.boost.org

boost::ptr_container: seems bug in erase_if
by Anton Ivanov 15 Feb '09

15 Feb '09

Hi! In ptr_sequence_adapter.hpp we have function: template< class Pred > void erase_if( iterator first, iterator last, Pred pred ) { range_check(first,last); this->base().erase( std::remove_if( first.base(), last.base(), void_ptr_delete_if<Pred,value_type>(pred) ), this->base().end() ); } If we call this function with second parameter not equal to this->base().end() then function remove not only elemets for wich pred return true, but also all alement from last.base() to the end of container (this->base().end()). This is seems bug due to function documentation: template< class Pred > void erase_if( Pred pred ); template< class Pred > void erase_if( iterator begin, iterator end, Pred pred ); * Requirements: Pred must take an const T& argument * Effects: removes all elements t for which pred(t) returns true from the entire container or the specified range -- Yours sincerely, Anton Ivanov (ai(a)drweb.com)

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Profiling template instantiations
by Steven Watanabe 12 Feb '09

12 Feb '09

AMDG Over the last few days, I've been working on a tool that counts the number of class template instantiations in a translation unit. To use it from a jamfile import profile_templates : : directory of the tool ; template-profile result : some_file.cpp : <include>some_directories ; If everything works, this will create a file with the extension .tp which will contain the number of times each class template was instantiated, with the most common templates at the top. I've put a zip of a rough version in the vault. http://www.boost-consulting.com/vault/index.php?action=downloadfile&filenam… Caveats: I've only tested with Visual C++ 9.0 and gcc 3.4.4 on cygwin so far. Other compilers won't work, yet. Other versions of these compilers may or may not work. It may be necessary to add link=static to the bjam command line. In Christ, Steven Watanabe

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Re: [boost] Profiling template instantiations (Steven Watanabe)
by PORKOLAB Zoltan 12 Feb '09

12 Feb '09

Hi Steven, We have created a framework for debugging/profiling template metaprograms in 2006. It might give you a few tips. It works based on the same idea you have. We instrument all template codes, both at the begining and at the end of each template we insert a special piece of code emitting warning messages of a well-defined form. Before instrumentation we create an XML file to remember the template positions in the source file. When we parse the warning, using this information we can reconstruct the instantiation stack knowing the original line numbers, identifiers, etc.. At the end we produce another XML for possible front-ends. The framework uses boost::spirit and boost::wave. We have also implemented and tested a visual studio plug-in. An overview of the whole idea: http://gsd.web.elte.hu/templight/ There is also a GPCE article about the framework, you can find it here: http://portal.acm.org/citation.cfm?id=1173746&coll=portal&dl=ACM&CFID=47731… or here: http://gsd.web.elte.hu/contents/articles/gpce06.pdf You can download both the VS binaries and the source from: http://people.inf.elte.hu/pocok Please feel free to use the code or any of the ideas. For technical question you can find Jozsef: jmihalicza(a)gmail.com or me. Regards, Zoltan

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[constrained] constrained_vector
by Neal Becker 09 Feb '09

09 Feb '09

I'm interested in something like constrained, but applied to a vector of values. The case I'm interested in is a homogeneous vector of bounded int values, with bounds set at runtime. It is trivial to have a vector<bounded<int> >, but this would not be space efficient in the case where the policies, bounds on all the values are the same. I'm thinking that maybe some parts of constrained (such as policies) could be reused, independent of the rest of constrained. Has anyone looked into the idea of constrained vector?

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[constrained_value] Review version
by Robert Kawulak 09 Feb '09

09 Feb '09

Hi all, I've made some minor changes to the Boost Constrained Value library: - reorganized the structure of header files, - renamed saturating/saturating_int into clipping/clipping_int, - using boost::swap where applicable (if you don't have it, you need to get it from http://svn.boost.org/svn/boost/branches/release/boost/utility/swap.hpp) - made no_constraint policy public, - now the stream operators are not defined if BOOST_NO_IOSFWD macro is defined, - fixed identifiers containing "__" (not allowed by C++), - fixed minor language errors in the docs. The library is ready for the formal review, which starts this monday (1.12). It is only missing the detailed regression tests, which will be added after the review. Currently the examples file (libs\constrained_value\doc\src\examples.cpp) can be used instead -- it uses most of the functionality of the library and should compile and run returning 0. As usually, the code and documentation can be downloaded here: http://rk.go.pl/f/constrained_value.zip The documentation is also available online here: http://rk.go.pl/r/constrained_value Any comments and problem reports for platforms that has not been tested yet are very welcome. Best regards, Robert Kawulak -=##############=- "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein

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[constrained_value] serialization
by Neal Becker 09 Feb '09

09 Feb '09

constrained_value does not currently support serialization. 1. Should it be added to the lib? 2. What would be a suggested implementation?

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[threadpool] new version - supporting future library (C++0x) from Anthony Williams
by k-oli＠gmx.de 09 Feb '09

09 Feb '09

Hello, I've uploaded a new version of boost.threadpool (v17) at http://www.boostpro.com/vault/index.php?action=downloadfile&filename=boost-…. It uses the future implementation of Anthony Williams (C++0x - available at http://www.justsoftwaresolutions.co.uk/files/n2561 future.hpp). Please save it as file 'future'. best regards, Oliver

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Re: [boost] [date_time] Time zone improvements
by Rutger ter Borg 07 Feb '09

07 Feb '09

Jeff Garland wrote: > Very cool :-) One question -- is there a portable solution where a user > could deploy a files onto a Windows system or is it a Unix only solution? Portable, big endian binary files. The variant I'm proposing is also based on the POSIX standard http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap08.html: "TZ This variable shall represent timezone information. The contents of the environment variable named TZ shall be used by the [snip] functions, and by various utilities, to override the default timezone. The value of TZ has one of the two forms (spaces inserted for clarity): :characters or: std offset dst offset, rule " The second variant is what's currently in Boost.Date_Time as Posix Time Zone, having a direct specification of the time zone. I'll be talking about the first variant, containing :characters. Although this is implementaiton specific, most POSIX-compatible systems have implemented the Zoneinfo database for this variant, e.g., Linux-based systems, many BSDs, Mac OS X, etc. The :characters point to any other zoneinfo-compatible binary file, either with an absolute or relative path. A natural step for changing Boost.Date_Time would be to make changes such that the Posix Time Zone supports both formats. I.e., variant 1) posix_time_zone( ":/etc/localtime" ); or posix_time_zone( ":/usr/share/zoneinfo/Europe/Amsterdam" ); variant 2) posix_time_zone( "EST-5EDT,M4.1.0,M10.5.0" ); I think both should work as it is from the same standard, and seems to be a natural and consistent starting point to look at changing the interface. Do you agree? > Actually, I believe the abstract timezone is able to support this, but > there > isn't a concrete implementation. It would be great to have the concrete > implementation to prove out the abstraction (obviously from the text below > you think there needs to be changes). As far as I can tell, the abstract time zone class currently is not able to represent variant 1): the abstract zone class is geared towards a single-lined definition of a time zone, whereas variant 1) may be regarded as a series of definitions, i.e., a map of < transition_time_point_in_utc, { gmt_offset, abbreviation, is_dst, ... } > looking up utc_to_local is a matter of doing a lower_bound search on the transition time points. The right-hand side of the map above is widely implemented with a struct called ttinfo. A proposal from my side would be to change the abstract time zone class in such way that it is able to represent both variants. The easiest approach here is probably to introduce the ttinfo structure, and make the current library working with that. variant 1): has a map of transition points, returns a (pointer to a) ttinfo structure. May hold more than 2 different ttinfo structures. variant 2): always has 2 ttinfo structures (std/dst). Uses dst-calculations/functions to lookup the transitions point, returns the right (pointer to a) ttinfo structure. What do you think? Cheers, Rutger

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support for gcc hidden visibility in shared libraries
by Stjepan Rajko 06 Feb '09

06 Feb '09

Hello, Many (almost all?) linked boost libraries don't work as shared libraries when compiled with the -fvisibility=hidden switch on gcc version>=4. I am wondering whether there is interest in making them work under these circumstances, as it might not be too hard to do, and there seems to be some benefit to it. To my limited understanding, making a symbol visible in a shared library using, say, __attribute__ ((visibility("default"))) on gcc, is analogous to using __declspec(dllexport) on windows. Many boost libraries already use macros that apply __declspec(dllexport) on windows - so these macros could set to expand to __attribute__ ((visibility("default"))) on gcc. Even better, a boost-wide macro could be added to the config headers. More information on this can be found here: http://gcc.gnu.org/wiki/Visibility Just to note, I have very limited understanding of compiling/linking and I might not have a full grasp of everything involved here. Also, my only reason for thinking that -fvisibility=hidden should be supported is that for a long time now, I haven't been able to use boost shared libraries on my os x platform, and only now I realized that the reason for this is that I had stuck -fvisibility=hidden in my user-config.jam a long time ago to suppress some warnings. Nonetheless, it seems like there are benefits to supporting it that go beyond preventing people like me from accidentally shooting themselves in the foot. Kind regards, Stjepan

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[threadpool] draft n2276 - launch_in_pool
by Oliver Kowalke 25 Jan '09

25 Jan '09

Hello, I did a look into draft n2276 - a launch_in_pool function is suggested (passing task to a system provided threadpool). Is it reasonable to have a static threadpool? How many worker-threads should this pool contain and how are the submitted tasks queued (FIFO, priority order ... unlimited/limited number of tasks can bes stored). What about applications which require a pool with different configuration than the static pool provides? Is it acceptable to pay for an unused pool? regards, Oliver -- Psssst! Schon vom neuen GMX MultiMessenger gehört? Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger

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