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[bind] bound object type introspection
by Gennadiy Rozental 14 Oct '09

14 Oct '09

Hi, Following the discussion on users list I came to conclusion it's impossible at the moment to deduce argument types of bound object passed to the function template. Is there any reason why this can't be added in the manner similar to the boost::function typedefs? Gennadiy

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math/tools/rational.hpp gcc 3.2 problem
by Ralf W. Grosse-Kunstleve 14 Oct '09

14 Oct '09

gcc 3.2 doesn't compile this code (works with gcc 3.3 and up): #include <boost/math/distributions.hpp> int main() { boost::math::students_t_distribution<double> dist(1.); dist.find_degrees_of_freedom(1.,2.,3.,4.,5.); return 0; } Reduced: template <unsigned N, class T, class V> inline V evaluate_polynomial(const T(&a)[N], const V& val) { return val * a[0] * static_cast<T>(N); } int main() { double a[3]; double val; double result = evaluate_polynomial(a, val); return static_cast<int>(result); } dbg2.cpp: In function `int main()': dbg2.cpp:12: no matching function for call to ` evaluate_polynomial(double[3], double&)' Does anyone have an idea for working around the problem? Ralf

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Formal Review Request: Generic Geometry Library (GGL).
by Barend Gehrels 14 Oct '09

14 Oct '09

Hi, We would like to ask for a formal review for the Generic Geometry Library (GGL). The GGL defines concepts for geometries and implements some algorithms on such geometries. GGL contains a dimension-agnostic, coordinate-system-agnostic and scalable kernel, based on concepts, meta-functions and tag-dispatching. On top of that kernel, algorithms are built: area, length, perimeter, centroid, convex hull, intersection (clipping), within (point in polygon), distance, envelope (bounding box), simplify, transform, convert, and more. The library is also designed to support high precision arithmetic numbers, such as GMP. GGL contains instantiable geometry classes, but library users can also use their own. Using registration macros or traits classes their geometries can be adapted to fulfil the GGL-concepts. The GGL might be used in all domains where geometry plays a role: mapping and GIS, gaming, computer graphics and widgets, robotics, astronomy... The core is designed to be as generic as possible and support those domains. However, for now the development has been mostly GIS-oriented. We propose the extension model, the same way as GIL also applies it. So we are going to help to organize development of GGL extensions, where an extension is (mostly) something more specific to domains like mentioned above. The proposed GGL has seen four previews, many discussions and many changes in design and implementation, based on those discussions. The last preview was in February '09. Since then the design of the library is stable and the library contains a variety of coherent functionality. So we feel that the library is matured enough for formal review. Therefore, I would like to request a formal review and the library placed into the review queue. It is put into the Boost.Sandbox: https://svn.boost.org/svn/boost/sandbox/ggl/formal_review_request We have a review manager. Regards, Barend Gehrels, Bruno Lalande, Mateusz Loskot

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[test] compile-fail tests with precise output
by Jean-Louis Leroy 14 Oct '09

14 Oct '09

I would like to create tests that check, not only that a file will not compile, but that the errors contain specific strings. More precisely, I want to make sure that wrong code fails on a MPL assertion and not deep inside the template instantiations. Is that feasible? Thanks, Jean-Louis

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[1.41.0] Beta planned for next week
by Beman Dawes 13 Oct '09

13 Oct '09

Looks like we are on schedule for a 1.41.0 beta next week. Now would be a good time for developers to: * Merge any stable changes from trunk to release. You can tell if there are unmerged trunk changes with the svn diff command, or use trunk/tools/release/unmerged.bat. * Check http://beta.boost.org/development/tests/release/developer/summary.html to make sure your library's tests are clean. Thanks, --Beman

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Name of namespace detail
by Mateusz Loskot 13 Oct '09

13 Oct '09

Hi, Inspired by Jean-Louis question about what to put to namespace detail, I would be interested learning about rationale of name of the namespace detail (sometimes details or impl too). Recently, I've participated in a very interesting discussion, on ACCU members mailing list, about prefixes and suffixes like Base or _base nad Impl or _impl, as misused, irrelevant and confusing, meaningless, etc. For example, how to properly name elements of PIMPL idiom and similar. During the discussion I suggested that 'detail' is a good name for namespace dedicated to implementation details being not a part of public interface of a component. I got answer that it as the same issues (it's meaningless) as Impl etc. It raised some questions for myself, being interested in improving my craft, I would like to learn better about the name of namespace detail. I use detail name myself. Any better names for bucket with implementation details? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org

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[signals2] combiner + groups -> topmost only (missing code)
by Oliver Kowalke 13 Oct '09

13 Oct '09

Hello, I need a combiner which executes only the slots within the highest group. How to access to group in the combiner? What happens with the input iterators if signal::disconnect_all_slots() gest called within the combiner? someting like this: struct combiner { template< typename It > void operator( It i, It e) const { // iterate over slots // execute only slots of highest group } }; signal< void(), combiner, int, greater< int > > sig; sig.connect( 0, slot1); sig.connect( 1, slot2); sig(); // only slot2 gets called regards, Oliver -- Jetzt kostenlos herunterladen: Internet Explorer 8 und Mozilla Firefox 3.5 - sicherer, schneller und einfacher! http://portal.gmx.net/de/go/atbrowser

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Deciding what to put in `namespace detail`
by Jean-Louis Leroy 13 Oct '09

13 Oct '09

For my future Boost.RDB submission, I feel tempted to put everything except the names that are in the public (documented) interface in a nested `namespace detail`. Why not even put *everything* there and copy selected names in the public namespace by means of using-declarations. Has it been already done ? And what about having three namespaces : a "public" one for the user, a "protected" one for those extending the lib, and a "private" one for undocumented internals? Opinions and advise welcome... J-L

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Workaround request: boost::shared_ptr & Intel C++ Compiler
by Marat Abrarov 13 Oct '09

13 Oct '09

Hi! I wrote about my problem before (Boost-users Digest, Vol 2116, Issue 1: "boost::options, boost::shared_ptr with Intel C++ Compiler 11.x") but didn't received any response yet. So here's a copy: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I use boost 1.40. I have a project at http://sourceforge.net/projects/asio-samples/ (only SVN trunk is available now) It uses MS C++ Compiler (9.0 SP1 - MS Visual Studio 2008 SP1) and boost::program_options (+ boost::asio + boost::...). When I switched that project (I mean "echo_server") to Intel C++ Compiler 11.1.038 (I tried all 11.1.x) and built debug version (Debug Win32) (with addition of option /vmg to compiler command line - stupid Intel :) it works fine except shared_ptr-to-bool cast (for example: include/ma/echo/server/session_manager.hpp: 319). This issue I found only at "Debug Win32" build mode - at "Debug x64" all is fine and the built executable (echo_server.exe) works right. When I build "Release Win32" or "Release x64", the built executable don't work at all - it fails somewhere at the boost::program_options (I think at std::vector<std::string>::operator= or std::vector<std::string> copy-constructor). Does anybody: 1) tried to use boost::shared_ptr 2) tried to use boost::prorgam_options with Intel C++ Compiler 11.1.x? P.S. If I change boost_1_40_0\boost\smart_ptr\detail\operator_bool.hpp: 9 - add "|| defined (BOOST_INTEL)" - then shared_ptr-to-bool cast works fine (Win32/x64 Debug/Release) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Does anybody has similar problems with Intel C++ Compiler and boost::shared_ptr? Is anybody from boost community interested for Intel C++ Compiler support? Regards, Marat Abrarov.

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[signals2] combiner + groups -> topmost only
by Oliver Kowalke 12 Oct '09

12 Oct '09

Hello, I need a combiner which executes only the slots within the highest group. How to access to group in the combiner? What happens with the input iterators if signal::disconnect_all_slots() gest called within the combiner? someting like this: struct combiner { }; -- Neu: GMX DSL bis 50.000 kBit/s und 200,- Euro Startguthaben! http://portal.gmx.net/de/go/dsl02

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[rdb] 0.1.00 - prepared statements
by Jean-Louis Leroy 11 Oct '09

11 Oct '09

I have uploaded version 0.1.0 to the vault. It introduces prepared statements and placeholders. No doc on this yet but it's easy to use, e.g. BOOST_AUTO(st, db.prepare(insert_into(p)(p.id, p.first_name, p.name, p.age).values(_, _, _, _))); st.execute(3, "Bart", "Simpson", 9); st.execute(4, "Lisa", "Simpson", 7); st.execute(5, "Maggie", "Simpson", 0); It also works with update, delete and select. Placeholders are allowed in predicates as well. Parameters are type-safe, if they don't agree with the type of their corresponding placeholder (as deduced by the context in which it is used), you will get a compilation error. More examples in the test file here : http://code.google.com/p/boost-rdb/source/browse/libs/rdb/test/test_odbc.cpp J-L

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[wave] 1.40.0 build problem on recent intel
by troy d. straszheim 10 Oct '09

10 Oct '09

Over on the boost-cmake Justin Holewinski pointed out that wave doesn't build on recent intel compilers. Details and fix here: http://software.intel.com/en-us/articles/error-409-when-building-boost-libr… -t

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Re: [boost] threads: how to remotely kill a thread?
by David M. Cotter 10 Oct '09

10 Oct '09

yes i have seen the error of my ways, and am now using thread.interrupt () and i sprinkle interruption_point() in my inner loops of the thread thanks for the feedback. -dave On Oct 9, 2009, at 9:20 PM, Yigong Liu wrote: > It is kind of dangerous for one thread to kill another thread > forcefully or directly, since the 2nd thread may be in the middle of > holding a system resource or changing some state. Killing it may > left the system in corrupted state. better using "cooperative" > shutdown, the 1st thread sends the 2nd thread some notification, > either thru shared state or interrupt. For similar reasons, java > deprecated many thread api (http://java.sun.com/j2se/1.4.2/docs/guide/misc/threadPrimitiveDeprecation.h… > ). > > On Fri, Oct 2, 2009 at 9:16 AM, Andrey Semashev <andrey.semashev(a)gmail.com > > wrote: > David M. Cotter wrote: > say i'm on the main thread, and i've got a thread::id of some other > preemptive thread. i do not have the actual boost::thread object > any more. > > and i want to unceremoniously kill that thread. like right now. > > how do i kill it? i don't see a way to recover the actual > boost::thread from the thread::id. but even if i could, and then > call thread.interrupt(), that's more of a polite request which is > free to be ignored, rather than a you_must_die_now() thing. > > The main problem with killing threads is that it doesn't unwind the > stack and thus breaks RAII. Therefore the best "official" way to > terminate the thread in C++ is to interrupt it. If you want to do it > the hard way, you're in C world with pthread_kill and alikes.

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[fusion] accumulate vs. std::accumulate
by Christoph Heindl 10 Oct '09

10 Oct '09

Hi, I'm currently confronted with an issue raised before [1] on this list: boost::fusion::accumulate takes its arguments in reverse order compared to std::accumulate. The issue is still marked as 'new' on trac [2]. What are the chances to have this issue fixed for the next release? Kind regards, Christoph [1] http://lists.boost.org/Archives/boost/2008/09/142490.php [2] https://svn.boost.org/trac/boost/ticket/2355

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[trunk] Missing Jamfile in Boost Root Directory
by Dean Michael Berris 10 Oct '09

10 Oct '09

Hi everyone, I just did an SVN update to the latest in Boost's trunk and I don't see a Jamfile in the root directory anymore. I ask because I do this in my project Jamroot, which used to work: import os ; local BOOST_ROOT = [ os.environ BOOST_ROOT ] ; use-project /boost : $(BOOST_ROOT) ; But now when running bjam it complains that it can't see a Jamfile in the BOOST_ROOT directory. Any workarounds for this? TIA -- Dean Michael Berris blog.cplusplus-soup.com | twitter.com/mikhailberis linkedin.com/in/mikhailberis | facebook.com/dean.berris | deanberris.com

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[MPI?] which API should i use for this?
by David M. Cotter 10 Oct '09

10 Oct '09

I have a need to send an "event" to the "main thread's event loop". this may be done from a preemptive thread, a cooperative thread, a timer, or even the main thread itself. i want it to be posted into the event stream and handled in the order that events get processed on the main thread. would i use 'MPI'? or 'interprocess'? or is there a 'thread' way to do this? if it's MPI, what would be the right call? i'm coming from Mac land where i have traditionally used PostEventToQueue()

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[Boost.Units] non-integral unit exponents
by Belcourt, Kenneth 09 Oct '09

09 Oct '09

Hi, I'd like to use Boost.Units but am unsure whether I can declare a unit like this: W/m^2 Pa^0.25 K^1.523 In addition, I'd like the ability to change the pressure (Pa) and temperature (K) coefficients at runtime (user supplied input might change the default coefficients). Are these things possible with Boost.Units and, if so, could someone point me to an example? (I need this for nucleate boiling curves). Thanks. -- Noel

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threads: linking on OSX
by David M. Cotter 09 Oct '09

09 Oct '09

I followed the instructions from here: http://www.boost.org/doc/libs/1_40_0/more/getting_started/unix-variants.htm… and it spent a bunch of time compiling everything. no errors. yay. so then i go to link my program, i added <boost dir>/stage/lib/ libboost_thread.a to my project, cuz that's how you static link, right? where <boost dir> is the location of the boost installation but it says: <boost dir>/bin.v2/libs/thread/build/darwin-4.2.1/release/threading- multi/libboost_thread.dylib, file is not of required architecture Undefined symbols: <long list of all the boost symbols i used> interesting that even by adding the .a file, it went and found the dylib? is that normal? anyway, wrong architecture?? how do i make it build universal? (PPC plus intel? and what's with the missing symbols? i'm not really a n00b, i just appear to be one today.

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[parameter] Ticket #3114
by Jeremiah Willcock 09 Oct '09

09 Oct '09

Would it be possible to have the feature requested by ticket #3114 (https://svn.boost.org/trac/boost/ticket/3114) implemented? This would make the Boost.Parameter library much more useful for situations where default argument types do not always exist. Thank you. -- Jeremiah Willcock

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[Property map] 1.40.0 breaks boost.graph python bindings
by John Reid 09 Oct '09

09 Oct '09

I'm using gcc 4.2.4 on Ubuntu. The boost.graph python bindings (http://www.osl.iu.edu/~dgregor/bgl-python/) work fine with boost 1.39. When I try with boost 1.40 I get many errors such as the following: ./boost/graph/python/resizable_property_map.hpp:101: error: ‘class boost::vector_property_map< boost::default_color_type, boost::graph::python::basic_index_map< boost::graph::python::basic_descriptor<boost::detail::edge_desc_impl<boost::bidirectional_tag, void *>, boost::bidirectionalS>, boost::adj_list_edge_property_map< boost::bidirectional_tag, long unsigned int, const long unsigned int &, void *, const boost::property<boost::edge_index_t, long unsigned int, boost::no_property>, boost ::edge_index_t>>>’ has no member named ‘get_store’ Does anyone know what changed between 1.39 and 1.40 to break this? The Readme.txt that comes with boost 1.40 suggests that nothing was updated in the property map library. BTW it doesn't compile with gcc 4.3 either but then neither does it compile with boost 1.39 (albeit for different reasons). I can provide all of the error messages if needed. John.

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[1.41.0] Cleaning up inspection errors
by Beman Dawes 09 Oct '09

09 Oct '09

The Inspection Report is showing 1292 problems reported. I'd like to drive that number way lower for the 1.41.0 release. The "Worst Offenders" list is: test (254) regression (145) gil (140) build (116) proto (75) See http://boost.cowic.de/rc/inspect-trunk.html Developers, please fix any problems in your library. Thanks, --Beman

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[program-options] Ticket #1132, multitoken() and zero_token()
by Sascha Ochsenknecht 09 Oct '09

09 Oct '09

Hello, I would like to have an option which allows multi token but not multiple occurrences of the option or at least a way to distinguish the occurrences: E.g. something like: program.exe --option value1 value2 I tried the following: 1) desc.add_options()("option", value<string>()->multitoken(), "help"); With the above command line I get exception: multiple values not allowed 2) desc.add_options()("option", value<vector<string> >(), "help"); Command line is parsed without error but only value1 is stored in the vector -> ERROR, should report 3) desc.add_options()("option", value<vector<string> >()->multitoken(), "help"); Command line is parsed without error both values are stored in the vector, but program.exe --option value1 --option value2 and program.exe --option value1 value2 leads to the same vector contents. With the current version it isn't possible to distinguish to occurrences of a certain option and it is not possible to implement an option which has the multitoken attribute but isn't allowed to occur several times. I'm willing to work on a patch for this issue, but first I want to discuss how to solve this, i.e. how the library should behave. The problem is possibly that specifying a list or vector implies that an option can occur multiple times. I think maybe following solution could work: 1) desc.add_options()("option", value<vector<string> >(), "help"); multiple occurrences of the option are allowed and pushed to the vector but only one value per option occurrence (like it is implemented now) 2) desc.add_options()("option", value<vector<string> >()->multitoken(), "help"); multiple occurrences of the option are NOT allowed, the multiple tokens/values are pushed to the vector 3) desc.add_options()("option", value<vector<vector<string> > >()->multitoken(), "help"); multiple occurrences of the option are allowed, the multiple tokens/values are pushed to the inner vector E.g. program.exe --option value1 value2 --option value3 --option value4 value5 This would result in the following storage sheme: { { value1, value2 } { value3 } { value4 value5 } } I'm not sure if a could become a friend of this implementation ... but it would work at least. Another way would be to join the multitokens into a single string: { "value1 value2" "value3" "value4 value5" } .. but this I don't like :-(. What do you think? Thanks & regards, Sascha PS: Is somebody working on ticket #1132 ??

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[rdb] 0.11
by Jean-Louis Leroy 08 Oct '09

08 Oct '09

In this drop : * Everything related to SQL composition has been moved to namespace boost::rdb::odbc * Update syntax has changed, instead of .set().set() chains it is now closer to SQL syntax (an deasier to implement): update(p).set(p.id = 1, p.first_name = "Homer") * Qualified table names: person::qualified p; partner::qualified l; select(p.id).from(p, l).where(p.id == l.wife) gives: select person.id from person, partner where person.id = partner.wife * in predicate: select(p.id).from(p, l).where(p.id.in(select(l.husband).from(l))) select(p.id).from(p).where(p.id.in(p.age + 1, 2)) * NULL: insert_into(p)(p.id, p.age).values(1, null) update(p).set(p.age = null).where(p.id == 1) select(p.id).from(p).where(p.age == null) Whoa! This gives: select id from person where age is null I'm only 80% sure about this one. Like everybody I suppose I have tried one day to compare with NULL, only to realize that the result is always false. After a while, ahem...So I have implemented operator == to do the right thing. It could have been: select(p.id).from(p).where(p.age.is_null()) Does anyone has an example where it makes sense to truly compare (using =) with NULL ? As for returning the NULL indicator when reading results, I chose not to use Boost.Optional (although I will probably add support for optional as well) because: 1. it would cost one bool (most likely the size of an integer) per column 2. IMHO the automatic conversion to bool is a bad idea 3. the value inside an optional<> cannot be addressed Instead I have complemented a fusion::vector with a std::bitset. The tutorial shows how to use this. I am hesitating a bit about pushing fusion::vector inside the implementation (i.e. nullable<int, char...> instead of nullable< fusion::vector<int, char> >). * Result sets: execute(Select) now returns a ResultSet object that allows retrieval row by row: also see the tutorial here : http://yorel.be/boost/libs/rdb/doc/html/rdb/tutorial.html#retrieve_data There is also a "Jumbo select" at the bottom of the tutorial that recaps everything that is supported for the moment. J-L

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[threads] wait() and signal() ?
by David M. Cotter 07 Oct '09

07 Oct '09

on the mac the notion of a semaphore is at a slightly higher level than a condition_variable. but it seems in boost::thread we must use the actual condition_variable. on the mac, with a semaphore, the value can be pre-set to signal, so that the next wait() is passed right thru, since the signal was sent ahead of time. eg: you could do this: Semaphore sem; // newly initialized semaphore, brand new, never waited upon sem.signal(); // you can pre-set the signal! // later in the code sem.wait(); // no wait, since signal was already sent // and later still sem.wait(); // now we wait in fact, actually, the way it actually happens on the mac is that a newly initialized semaphore comes IN WITH the semaphore pre-signaled. so you actually have to call wait() immediately to eat that signal. i've got lots of code that does this: Semaphore sem; sem.wait(); // eat the first signal i thought that was normal. trouble is,i've got lots of code that does NOT eat that first signal, depending on the first wait call to be passed thru immediately. this is the code that now breaks. in converting to boost::thread, there doesn't seem to be a way to pre- set the signal. or to reset the state of a semaphore from an unknown state to a known state, eg this code: sem.signal(); sem.signal(); sem.wait(); that guarantees that the next wait will actually wait, regardless of the state of the sem before hand. how can i do this with boost::thread ?

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[rdb] Repository, contributing, copyright, etc
by Jean-Louis Leroy 07 Oct '09

07 Oct '09

* Respository I have set up a Mercurial repository for rdb. You can get a copy with this command: hg clone https://boost-rdb.googlecode.com/hg/ boost-rdb You can view the source without installing Mercurial at that URL. * Contributing For those who consider contributing: I would like to keep clear copyright on this work. I propose the following arrangement: if you send me a patch that touches any of my copyrighted files, and I decide to use it, then you agree to transfer the copyright on the entire patch content to me. In return, I guarantee: 1/ the files touched by the patch will remain available under the Boost license 2/ you will get credit for it in the "Acknowledgements" section of the doc. If you create a set of files that is independant from mine and wish to put it in the distributions or in the repository, then you retain the copyright on them and set the rules you want. What I have in mind here is a native binding to a database. I hope that by next year we will have native bindings for all the major databases and obviously I am not going to write them all by myself. * Please help I am looking for the sql 2003 syntax expressed as a graph, preferably available online. Books suggestions are welcome too. * Extensibility For a small touch of technical stuff in this mail: I am trying hard to make it easy to support the various dialects. Here is a proof of concept (add MySQL LIMIT clause): https://boost-rdb.googlecode.com/hg/libs/rdb/doc/examples.cpp J-L

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