July 2010 - Boost - lists.preview.boost.org

Does boost help in creating generic function wrappers?
by Andy Venikov 16 Jul '10

16 Jul '10

In c++0x, creating a generic function wrapper is a bliss: template <typename Func> class gen_wrapper { Func && func_; public: gen_wrapper(Func && in) : func_(in) {} template <typename ... Prms> /*deduce result here */ operator() (Prms && ... prms) { //Do something special here. //NOTE: we can operate with arguments here too return func_(std::forward<Prms>(prms)...); } }; That's it. But if I don't have C++0x, can boost help here? functional/forward_adapter won't work since it hides function parameters, it only lets you operate with the function. It looks like it may be possible to do that by using boost/preprocessor I'll have to generate a whole lot of overloads with O(2^N) (because of the overload on (T &) or (T const &) for every argument). But it looks pretty dounting. It's basically what forward_adapter had to do. Isn't there a ready-made library that would allow me to generate all of the overloads? Thanks, Andy.

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status of logging library
by Torri, Stephen CIV NSWCDD, W15 16 Jul '10

16 Jul '10

What is the status of adding a logging library to Boost? I was looking at Boost.Log and Pantheios. I would like to not have to had another library to depend on. Stephen Stephen Torri, PhD NAVAL SURFACE WARFARE CENTER DAHLGREN 17214 Ave B Suite 121 Dahlgren, Va. 22448 540-653-1082 I am not a contracting officer. I cannot modify or initiate contracts, nor do I have the authority to financially commit the government in any way.

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Michael Herchel is ooo.
by Michael.Herchel＠rohde-schwarz.com 16 Jul '10

16 Jul '10

Ihre Nachricht betreffend: / Your Mail about: Boost Digest, Vol 2974, Issue 2 Ich werde ab 16.07.2010 nicht im Büro sein. Ich kehre zurück am 26.07.2010. Ich werde Ihre Nachricht nach meiner Rückkehr beantworten. I am on vacation and will be back in the office on 26.07.2010. I will reply your email as soon as I am back.

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[gsoc] Pointer Plus Bits Behavior and Interface
by Brian Bartman 16 Jul '10

16 Jul '10

Hello, Pointer Plus Bits: Is a data structure which points to specifically aligned object such that the value of the address is divisible by a power of two (the power of two which it is divisible by is given as a template argument). The empty bits of the pointer are then used to store extra boolean values relating to something (This is of the programmers choosing but it would seem best practice to make it related to the object being pointed at). The technique is of storing extra bits inside of pointers is some times referred to as bit stuffing. Clang uses this technique for their QualType pointer: http://clang.llvm.org/doxygen/classclang_1_1QualType.html So here are some of the questions I would like to pose to the community about the behavior and interface of the pointer_plus_bits data structure: 1) Should the pointer_plus_bits have a pre and post increment and decrement ( what about supporting other arithmetic operations such as add, minus, add assign etc...) ? One could do this if the sizeof the type is evenly divisible by 2 to the number of bits being "stuffed". The next/previous object in the array being traversed could be correctly pointed at (assuming that the item being pointed at IS an array). 1.a) If this is a behavior supported by the pointer_plus_bits should it keep the bits being stuffed or set them to zero each time? 2) Should the bits being stuffed apply during comparison? 3) Should the pointer provide compatibility between itself and pointer of the same type that is being stuffed (the behavior of this would mean masking out the pointer so the stuffed bits won't apply during the comparison)? (ie Should pointer_plus_bits<T,2> be comparable to T* ?) (in pointer_plus_bits 2 is the number of bits being stuffed). -- thanks, Brian Bartman

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Boost.Test - Looking for a gui.
by Giorgio Zoppi 16 Jul '10

16 Jul '10

Hi, i'm looking for a gui which it's able to launch tests and test suites for using with Boost.Test. Cheers, Giorgio. -- Quiero ser el rayo de sol que cada día te despierta para hacerte respirar y vivir en me. "Favola -Moda".

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Michael Herchel is ooo.
by Michael.Herchel＠rohde-schwarz.com 16 Jul '10

16 Jul '10

Ihre Nachricht betreffend: / Your Mail about: Boost Digest, Vol 2974, Issue 1 Ich werde ab 16.07.2010 nicht im Büro sein. Ich kehre zurück am 26.07.2010. Ich werde Ihre Nachricht nach meiner Rückkehr beantworten. I am on vacation and will be back in the office on 26.07.2010. I will reply your email as soon as I am back.

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bjam move in svn
by Vladimir Prus 15 Jul '10

15 Jul '10

I've just moved tools/jam into tools/build/v2/engine. This is a technical step towards unified packaging and release management of what is essentially a single tool, not two independent things. There are not other changes for now, but given that many folks might have tools/jam written in some scripts, I though I'd mention this. The change is on trunk only, so should not affect testing. Anyway, let me know if something breaks. Thanks, -- Vladimir Prus http://vladimir_prus.blogspot.com Boost.Build: http://boost.org/boost-build2

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mpi test question
by Robert Ramey 15 Jul '10

15 Jul '10

I'm still struggling to get serialization verioning correct. Is there anyway I can run mpi serialization tests on my win32 machine w/o mpi installed? Robert Ramey

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[lists] how to add a new boost mailing list?
by Eric Niebler 15 Jul '10

15 Jul '10

I'd like to set up proto(a)lists.boost.org for use by myself and a few other folks interested in discussing Proto and DSEL design issues. I could just use Google Groups (the Spirit lists use lists.SF.net, I see), but lists.boost.org would be better IMO. Does anybody know how to do this? -- Eric Niebler BoostPro Computing http://www.boostpro.com

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Bits and Ints: Intention Request
by Murilo Adriano Vasconcelos 15 Jul '10

15 Jul '10

Hi, I am working on GSoC Bits and Ints project wich is a library with functions for integral data types. The motivation for this library is to provide integer algorithms and utilities optimized by doing binary manipulations so that it uses less CPU cycles, memory access and conditional branches. This library contains some classical integer algorithms such as population count, reversing bits, sign extension and bit interleaving. Would be great to Boost to incorporate this library because its functions can be used on a widely types of applications that needs to perform fast operations on integral types. Since one of slowest operations perfomed by the CPU is conditional braching (it involves pipelining, recaching, etc) this library avoid it. For the runtime versions, conditional branch is not used (if, switch, for, while, etc). Other motivation to adopt this library is the integration with Boost.MPL. Almost every function implemented have it MPL and non-MPL static version. For example: // Runtime int pop_count(uintmax_t value); // non-MPL metafunction template <uintmax_t Value> struct static_pop_count {}; // MPL template <typename IC> struct pop_count : integral_c<int, static_pop_count<IC::value>::value> {}; The contents of this library is inside of boost/integer folder and can be viewed in [0]. The static and MPL compatible metafunctions are declared on headers with static_ prefix. The partial documentation can be viewed in [1]. What already is implemented (underlined are out of proposal) - Sign extension from a length of m bits to a length of n - Bit reversal - Bit-interleaving and uninterleaving - Programming utilities for bit and bitmask manipulation - Sign function - Transfer of sign - Clear Least-Significant Nonzero Bit - Round Up or Down to Next Power of 2 - Count Trailing Zeros - Population Count - *Integer Log2* - *Count Leading Zeros* - Compile time MPL compatible abs - Compile time MPL compatible lcm - Compile time MPL compatible gcd - Safe average functions - Swap without a temporary - Templated class is_integral_constant<> My plan is to implement these functions: - Run-time GCD - Run-time LCM - Functions for getting carry bits from addition and the high-half of an integer multiply - Rounding right-shifts - Saturating arithmetic operations - Multi-word shifts - Two-word divide by one-word value - Bounds Checking - Power of 2 Crossing - Find First String of 1-Bits of a Given Length - Incrementing a Reversed Integer - Decoding a “Zero Means 2n” Field - Integer Log Base 10 I want to know wich functions you think that it is interesting to implement in this library. Also, comments and suggestions are appreciated. [0] - http://svn.boost.org/svn/boost/sandbox/SOC/2010/bits_and_ints/boost/integer/ [1] - http://svn.boost.org/svn/boost/sandbox/SOC/2010/bits_and_ints/libs/integer/… References: http://aggregate.org/MAGIC/ http://graphics.stanford.edu/~seander/bithacks.html http://bits.stephan-brumme.com/ http://www.boost.org/doc/libs/1_35_0/libs/integer/index.html Hacker's Delight / Henry S. Warren, Jr Regards, -- Murilo Adriano Vasconcelos http://murilo.wordpress.com

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Is svn.boost.org down?
by Marshall Clow 14 Jul '10

14 Jul '10

I can't get to Trac. I can't check out from SVN. [ 0810 PDT ] -- Marshall

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[uuid] - test fail for gcc-mingw-4.3.3
by Andy Tompkins 14 Jul '10

14 Jul '10

Hi, I'm hoping someone can help me figure out why the following test fails. See http://tinyurl.com/2w796gq It appears that it compiles but there is such little information I don't know what it wrong. Thanks Andy.

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[Docs] Where's the documentation on compare_pointees.hpp?
by Mostafa 14 Jul '10

14 Jul '10

Hi all, Is there any mention in the docs on compare_pointees.hpp? (I couldn't find any.) I came across it was via some convoluted Google searches, after exhausting the boost docs route. -Mostafa

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Suggested change to type_traits/function_traits
by Joseph Garvin 14 Jul '10

14 Jul '10

I only just now subscribed to this list so forgive me if this has been suggested and rejected before. Currently function_traits<F> exposes the argument types for F as individual typedefs, arg1_type, arg2_type, etc. I think this could be made more powerful with two changes: 1. First, change it to be 0 indexed, arg0_type should be first. This is more consistent with the rest of boost and C++ in general. 2. Have an inner arg struct, templated over an integer indicating which argument you want. So instead of: typedef some_type arg0_type; typedef some_other_type arg1_type; //... You would have: template<int i> struct arg template<> struct arg<0> { typedef some_type type; } template<> struct arg<1> { typedef some_other_type type; } // etc. I think this would make function_traits more usable for metaprogramming. As is, to access the different argN_types you have to resort to using boost preprocessor. For backwards compatibility the old interface could co-exist with the new one.

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Boost format hex issue..
by Rob Kramer 14 Jul '10

14 Jul '10

Hi, I'm having an issue with boost::format, in that I can't get it to format a value as hexadecimal if that value is of float type. For example, the little test program below prints: "As int: 0018, 0x0012, as float: 0018, 0x0018" This is as intended, I suppose, since floats can't printed in hex form anyhow. But is there anyway I can get the 'x' format type attribute to interpret the value as integer? Simply casting it to int is not an option, because the way my float value is interpreted should depend only on the format string. I added a hack to my application that fixes it for now, but that doesn't seem very correct: boost::format (..) fmt; double v = ..; if (fmod (v, 1.0) == 0.0) fmt % (int) v; else fmt % v; Cheers! Rob #include <iostream> #include <iomanip> #include <boost/format.hpp> using namespace std; int main() { cout << "As int: " << boost::format ("%1$04d, 0x%1$04x") % 18 << ", as float: " << boost::format ("%1$04d, 0x%1$04x") % (double) 18 << endl; }

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member function traits (was: Concept Traits Library)
by Barend Gehrels 14 Jul '10

14 Jul '10

Hi, Related to this message: John Maddock wrote: >> Even if the library doesn't provides an approach that works to define >> all >> the concepts, it has a lot of useful things. I also suggested to >> Terje at >> least to add the mpl and type traits extensions of the library. > > Agreed - in fact I don't see why we can't just add the new traits > direct to the type_traits library? > > Certainly if someone would like to package these up as direct > additions to type_traits (so I don't have to do much!) then I'd > certainly look favorably on adding them. > and especially related to the function_traits of the type_traits library. Is there any interest in class member function introspection? According to the current documentation, "function_traits is intended to introspect only C++ functions of the form R (), R( A1 ), R ( A1, ... etc. ) and not function pointers or class member functions.". We have, in our work on Boost.Geometry, the need to have the function_traits also working on class member functions. We first had defined a specific meta-function, only for the purpose of concept-checking. Bruno suggested that using function_traits we can avoid that. So we need it to work on member functions. I did some experiments and it is possible to let function_traits checking member functions as well, and it is easy to incorporate into function_traits. It can then be called, for a member function called "apply" of a (template)class called Strategy, like this: typedef typename boost::function_traits<typename BOOST_TYPEOF(&Strategy::apply)>::arg1_type ptype1; for the first argument (in our case a point type, which is then used in the concept-checking using BCCL, to check if it fulfills the point concept and to feed into this same apply method). Adding member function support only needs two relatively simple additions: 1) a specialization for member functions, like this (here only for a const function with 2 parameters) template <typename Class, typename R, typename T1, typename T2> struct function_traits_helper<R (Class::*) (T1, T2) const> { BOOST_STATIC_CONSTANT(unsigned, arity = 2); typedef R result_type; typedef T1 arg1_type; typedef T2 arg2_type; }; 2) the boost::add_pointer call in function_traits should be avoided for member functions, this can be solved by using a meta-function there: template<typename Function> struct function_traits : public detail::function_traits_helper < typename mpl::if_ < boost::is_member_function_pointer<Function>, Function, typename boost::add_pointer<Function>::type >::type > {}; Experiments are here: http://codepad.org/Qw4Uf1aG So I have a prototype, it seems to work fine and can easily be extended and incorporated. Is there more interest in it, and do the type_traits maintainers find this a good idea? Of is it already somewhere else within Boost (or planned)? Regards, Barend

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Required disk space for test runner
by Michael Caisse 13 Jul '10

13 Jul '10

I just noticed my boost test runners are failing because 25GB of space is no longer enough. I could randomly start making the VM drives larger but since that is such a pain in the MS guest OS I am hoping somebody can provide guidance on how much space is currently required. Thanks - michael -- ---------------------------------- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com

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[1.44] Asking for permission to merge Spirit patches
by Hartmut Kaiser 13 Jul '10

13 Jul '10

Hey, I would like to ask for permission to merge a couple of outstanding Spirit patches to the release branch. These improve Spirit's compatibility with gcc 3.4.x, vc7.1 and Intel/Darwin. I had to wait for the tests to cycle before I could merge them. We have people waiting for those patches to be released. https://svn.boost.org/trac/boost/changeset?reponame=&new=63942@trunk%2Fboost &old=63938@trunk%2Fboost https://svn.boost.org/trac/boost/changeset?reponame=&new=63924@trunk%2Fboost &old=63923@trunk%2Fboost https://svn.boost.org/trac/boost/changeset?reponame=&new=63908@trunk%2Fboost &old=63902@trunk%2Fboost This one adds a new (minor) feature, which I missed to merge during the release preparations. It is well tested, shows no regressions on any platforms, and was supposed to be released (the related docs have been merged already): https://svn.boost.org/trac/boost/changeset?reponame=&new=63891@trunk%2Fboost &old=63838@trunk%2Fboost Regards Hartmut --------------- Meet me at BoostCon www.boostcon.com

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[Filesystem] Add features to list all mount paths, determine mount path of a path
by Daniel Trebbien 13 Jul '10

13 Jul '10

John Reynolds came up with a great idea for a possible extension to Boost Filesystem, in response to a question on the Boost Users' List about listing all available drives on Windows. The basic idea is to have the ability to list mounted filesystems. I then suggested that `basic_path` could be extended with a new member (e.g.: `mount_path`) that will determine the mount path of the given path, and add a function to iterate over all mount paths. Before I open a feature request, I wanted to ask some questions: 1. Has this idea been discussed before? 2. Is `mount_path` a good name for this? 3. What would be a good name for the function to iterate over all mount paths? 4. Is the concept of mount paths cross-platform?

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[Query] on Boost.Porcess
by Alapkumar Sinha 13 Jul '10

13 Jul '10

Hi, I am trying to check if there is library for "process" in boost. I came across the following link http://www.netbsd.org/~jmmv/process/index.html . But I am not able to find the boost process header files in the boost library I downloaded. Can someone tell me whether it is part of the boost library or not. If not, is there any other library for the same purpose. I am planning to use boost libraries, but there is a need for process creation as well. So do I have to use the POSIX calls instead? Regards, Alap ________________________________ This Email may contain confidential or privileged information for the intended recipient (s) If you are not the intended recipient, please do not use or disseminate the information, notify the sender and delete it from your system. ______________________________________________________________________

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Vault - multiple C/C++ files versus a compressed one
by vicente.botet 13 Jul '10

13 Jul '10

Hi, "jvd" you have uploaded all these files on the vault. It would be great if you upload a compressed file at once instead, and remove the C/C++ files. Best, Vicente sobol.hpp Home/Random 11.8 Kb 17.06.2010 20:56 niederreiter_base2.hpp Home/Random 13.38 Kb 17.06.2010 20:56 faure.hpp Home/Random 10.26 Kb 17.06.2010 20:56 gray_coded_qrng_base.hpp Home/Random/detail 3.03 Kb 17.06.2010 20:45 out-sobol.png Home/Random/images 19.31 Kb 17.06.2010 20:31 out-niederreiter_base2.png Home/Random/images 19.6 Kb 17.06.2010 20:30 out-faure.png Home/Random/images 11.84 Kb 17.06.2010 20:30 0 dim2demo.cpp Uses all quasi random kernels to output quasi-randomly distributed points. Home/Random 2.54 Kb 17.06.2010 20:29 4 quasi_random_number_generator_base.hpp Home/Random/detail 4.69 Kb 17.06.2010 20:27 _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/

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[BGL][Serialization] Error with edge_desc_impl
by Ireneusz Szcześniak 13 Jul '10

13 Jul '10

Hi, I have a problem serializing a graph in my code. I distilled the problem into this program: #include <boost/graph/adjacency_list.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/graph/adj_list_serialize.hpp> using namespace boost; class test; typedef adjacency_list <vecS, vecS, undirectedS, property<vertex_name_t, test> > Graph; typedef Graph::edge_descriptor Edge; class test { public: Edge t; template<class Archive> void serialize(Archive & ar, const unsigned int) { ar & t; } }; int main() { Graph g; boost::archive::text_oarchive oa(std::cout); oa << g; return 0; } This is the error message that I get: /usr/include/boost/serialization/access.hpp:109: error: ‘class boost::detail::edge_desc_impl<boost::undirected_tag, unsigned int>’ has no member named ‘serialize’ If I remove the field "t" of type Edge in the class "test", I don't get this error. I would appreciate it, if someone could point out where the problem is. Thanks, Irek -- Ireneusz (Irek) Szczesniak http://www.irkos.org

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permission to merge for 1.44 release (boost/python)
by Ralf W. Grosse-Kunstleve 12 Jul '10

12 Jul '10

I'd like to ask permission to merge boost/python and libs/python from the trunk into the release branch. The diffs are fairly small: http://cci.lbl.gov/~rwgk/tmp/boost_python_release_branch_merge_2010_07_12 Most changes have been in the trunk for a while (several weeks at least). The builtin_converters.hpp change is in the trunk for about a week. It only affects one platform, 64-bit Windows, on which it is very well exercised, far beyond the regular boost tests. It changes the behavior of Boost.Python under 64-bit Windows, therefore it seems important to me to merge the patch into the release as soon as possible; I'm guessing the number of users on this platform is currently very small but will increase significantly in the future. The module_init.hpp patch is in the trunk for a few days only but also extensively tested. It seems very unlikely to me that it could cause problems. Ralf

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Does lock-free boost::shared_ptr<T> implementation exist?
by Anqing Xu 12 Jul '10

12 Jul '10

Hi, I'm trying to find a production quality lock free reference counted pointer implementation and boost::shared_ptr seems promising. However boost::atomic_is_lock_free(shared_ptr) returns false on Windows. I'm going to try on SUSE linux soon. According to http://www.boost.org/doc/libs/1_43_0/libs/smart_ptr/shared_ptr.htm, Starting with Boost release 1.33.0, shared_ptr uses a lock-free implementation on the following platforms: GNU GCC on x86 or x86-64; GNU GCC on IA64; Metrowerks CodeWarrior on PowerPC; GNU GCC on PowerPC; Windows. Then why does boost::atomic_is_lock_free(shared_ptr) returns false? Is there any compiler flag that needs to be set? I also found another lock free reference counted pointer, atomic_ptr from Joe Seigh here http://sourceforge.net/projects/atomic-ptr-plus/files/ but it seems to support linux with GCC only. Documentation is also poor. -Anqing

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Concept Traits Library
by Edward Diener 12 Jul '10

12 Jul '10

I discovered, from asking a question on the user NG, the Concept Traits Library ( mentioned at https://svn.boost.org/trac/boost/wiki/LibrariesUnderConstruction#Boost.Conc… ) in the Boost sandbox by Terje Slettebø and Tobias Schwinger last dated almost 6 years ago. From e-mailing Terje Slettebø I discovered that he did not have time to work on it further or submit it to Boost, since he has been working in other areas for many years as part of his job. Tobias Schwinger's e-mail address was not in the documentation so I was not able to contact him. Other Boost TMP programmers also seemed to have helped to contribute to this library. How did this library slip under the raider, so to speak ? This is a fantastic library with many useful metafunctions for the TMP programmer. For my own particular use the operator metafunctions alone are incredibly useful, but there are many more metafunctions testing for many concepts covering the STL and MPL. The documentation is also very good and there is a complete set of tests. Have I missed anything in terms of other later libraries superceding the functionality that was in this one ? Are the techniques used in this library flawed in any way ? I would love to see this library as part of Boost, if just for the operator metafunctions, and have told Terje Slettebø so.

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