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

[network] 0.9-devel and BOOST_NETWORK_NO_LIB
by Dean Michael Berris 07 Mar '11

07 Mar '11

Hi Everyone, I just recently finished a consulting project that tied me up good the past three months. Now that I'm pretty much free again to work on cpp-netlib, I went for the things that have been brought up most recently on the list (and the Boost developers mailing list): 1. The server tests that used a different port each, configurable at the command-line with a default. This is already in 0.9-devel. 2. An option to turn off the required external library to be linked with a macro (BOOST_NETWORK_NO_LIB). With this macro defined before any cpp-netlib headers are included (or on the command line) the functions that were made extern or just free functions at namespace level are marked 'inline' and have their definitions pulled in accordingly in each translation unit. This addresses Jeff Garland's and others' concern of the need for an external library when using cpp-netlib when it's always been header-only until 0.9. I'm still wrestling with the thought of making the header-only behavior a default, but I'm not married to the "external library as default" decision either. 3. A consistent look/view between server-side request/response objects and client-side request/response objects. Now they can be dealt with using the same directives and modifiers. 4. Starting to change the library name to Boost.Network (after the suggestions). #2 is still undocumented, but I am going to be including a Doxygen-Sphinx bridge that would allow us to write documentation in-line on the types and have Doxygen invoked when the Sphinx documentation is built. I found a Sphinx extension to do that and it looks like it can be bundled with cpp-netlib as well (because it's under a BSD license) -- it's called "breathe" and can be found here: http://michaeljones.github.com/breathe/ #3 has been in the branch for a while already and it should be doable to back-port some of the things to the 0.8 line. #4 is largely a documentation matter. I have decided that in order for the development of the network library to scale, that I would spear-head a mini-community effort that would be called "The C++ Network Library Project" taking in a diplomatic and consensus-building approach. This way those willing to contribute to the effort can help with setting the direction of the library, the design decisions, etc. with me starting as the "benevolent dictator" and letting more people jump into the fray and becoming co-maintainers and regular contributors. There are already a couple of people (Oleg Malashenko and Emre Turkay) who have recently contributing to the project that I would like to thank, and also give the chance to get a bigger role in the development of the library going forward. So for now the focus is still to get a review-ready library for inclusion in Boost that would be called Boost.Network. I think 0.9 will be ready in a couple of days and will be a the pre-1.0 snapshot that will be submitted for review, getting all the required documentation in place. At this time I'm still looking for able and willing review managers. Feedback would be most definitely appreciated. -- Dean Michael Berris http://about.me/deanberris

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[asio] negating address_configured
by Alexander Lamaison 06 Mar '11

06 Mar '11

What is the correct way to negate the (default) resolver flag, address_configured? On Windows, at least, specifying address_configured (which translates to AI_ADDRCONFIG) has a nasty side effect. If the 'external' network is down, the resolver can no longer resolve the "localhost" address. More here http://src.chromium.org/viewvc/chrome/trunk/src/net/base/host_resolver.cc?r… address_configured is the default flag for ip::basic_resolver_query so I need to specify a flag that turns it off. In the underlying addrinfo struct this would just mean specifying 0 as the flag but that isn't an option with ASIO as far as I can tell. How would I do this? Thanks! Alex -- Easy SFTP for Windows Explorer (http://www.swish-sftp.org)

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Boost::asio, complexity
by Dhaivat Pandya 06 Mar '11

06 Mar '11

Hello everyone. I've been using Boost::Asio recently for tasks that one would often use languages such as Python or Perl for (e.g. sending GET requests), but I use C++ and ASIO since: 1) I need substantial speed 2) I just like C++ However, I notice that even though Asio works wonderfully for larger, asynchronous projects, it gets in the way while doing smaller, more routine tasks. And, asio also is not a miniscule library and when creating binaries, one is often including things he/she wouldn't need. So, I wrote a small library (<500 LOC) that basically lets you pretend that a socket is a stream and you can use it like std::cout and std::cin. Would anyone consider having this included in the Boost repository, or even merged with Asio (the former is preferable because of the binary size reason)? It currently works on Linux, and I'm working on compatibility with Windows. An example of code you can write with it: http://ideone.com/2GHe5 (GETs data from google.com) Right now, all calls are blocking, so that non-blocking can be done with Asio, which is more powerful.

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Help needed to reconnect a socket to a new endpoint with Boost asio in Windows
by Adolfo Jimenez 06 Mar '11

06 Mar '11

I'm having trouble when in Windows XP, try to connect a socket to an endpoint after being connected to another. This is the situation: a) The boost::asio::ip::tcp::socket is connected to a remote host (say pop.remote1.com) b) The transmission ends, and the socket is closed: socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both, error); socket_.close(error); Then, when trying to connect to another host (say pop.remote2.com) using the same process that in a), the proccess returns without error, but the socket remains closed. Note that when using pop.remote2.com as the first connection, the things run Ok, and the same problem arises if try to connect to pop.remote1.com after closing. In both situations there are not pending processes in the attached io_service. I tried to open the socket before the reconnection, but the result remains the same. That is, the result is the same if after closing the previous connection with. socket_.shutdown(...); socket_.close(...); is used socket_.open(...); socket_.async_connect( ... ); or just socket_.async_connect( ... ); The questions are: Is that reconnection admissible? Is that the supposed correct process? Thanks in advance.

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Boost.fusion 1.42 / Gcc 4.5: what is this error trying to tell me? (Works with Gcc 4.4)
by Joost Kraaijeveld 06 Mar '11

06 Mar '11

Hi, I have code that compiles OK with Gcc 4.4 but fails with 4.5 and I cannot understand what the error I get from the compiler means. Maybe someone here can give me a suggestion? The error: In file included from /usr/include/boost/fusion/algorithm/query/find.hpp:13:0, from /usr/include/boost/fusion/sequence/intrinsic/has_key.hpp:12, from /usr/include/boost/fusion/sequence/intrinsic.hpp:16, from /usr/include/boost/fusion/sequence.hpp:12, from ../../../library/../include/Danu/DanuModelObjects/User.hpp:11, from ../../../library/../include/Danu/DanuViewObjects/UserViewObject.hpp:12, from ../../../library/../include/Danu/DanuViewObjects/UserDialog.hpp:15, from ../../../library/../include/Danu/DanuModelObjectsFactory/UserCreatorFunction.hpp:10, from ../../../library/DanuModelObjectsFactory/UserCreatorFunction.cpp:7: /usr/include/boost/fusion/iterator/key_of.hpp: In instantiation of 'boost::fusion::result_of::key_of<mpl_::arg<1> >': /usr/include/boost/mpl/aux_/preprocessed/gcc/template_arity.hpp:85:88: instantiated from 'const int boost::mpl::aux::template_arity_impl<boost::is_same<boost::fusion::result_of::key_of<mpl_::arg<1> >, Danu::UserCreator::objectId>, 1>::value' /usr/include/boost/mpl/aux_/preprocessed/gcc/template_arity.hpp:93:261: instantiated from 'const int boost::mpl::aux::template_arity<boost::is_same<boost::fusion::result_of::key_of<mpl_::arg<1> >, Danu::UserCreator::objectId> >::value' /usr/include/boost/mpl/aux_/preprocessed/gcc/template_arity.hpp:98:30: instantiated from 'boost::mpl::aux::template_arity<boost::is_same<boost::fusion::result_of::key_of<mpl_::arg<1> >, Danu::UserCreator::objectId> >' /usr/include/boost/fusion/algorithm/query/detail/find_if.hpp:184:9: instantiated from 'boost::fusion::detail::static_find_if<boost::fusion::basic_iterator<boost::fusion::map_iterator_tag, boost::fusion::map<boost::fusion::pair<Danu::UserCreator::objectId, Danu::ObjectId>, boost::fusion::pair<Danu::UserCreator::userId, int>, boost::fusion::pair<Danu::UserCreator::userName, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::password, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::firstName, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::infix, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::lastName, std::basic_string<char> > >::category, const Danu::UserCreator::UserCreationArguments, 0>, boost::fusion::basic_iterator<boost::fusion::map_iterator_tag, boost::fusion::map<boost::fusion::pair<Danu::UserCreator::objectId, Danu::ObjectId>, boost::fusion::pair<Danu::UserCreator::userId, int>, boost::fusion::pair<Danu::UserCreator::userName, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::password, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::firstName, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::infix, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::lastName, std::basic_string<char> > >::category, const Danu::UserCreator::UserCreationArguments, 7>, boost::is_same<boost::fusion::result_of::key_of<mpl_::arg<1> >, Danu::UserCreator::objectId> >' /usr/include/boost/fusion/algorithm/query/find.hpp:46:43: instantiated from 'boost::fusion::result_of::find<const Danu::UserCreator::UserCreationArguments, Danu::UserCreator::objectId>' /usr/include/boost/fusion/sequence/intrinsic/at_key.hpp:37:17: instantiated from 'boost::fusion::extension::at_key_impl<boost::fusion::map_tag>::apply<const Danu::UserCreator::UserCreationArguments, Danu::UserCreator::objectId>' /usr/include/boost/fusion/sequence/intrinsic/at_key.hpp:70:9: instantiated from 'boost::fusion::result_of::at_key<const Danu::UserCreator::UserCreationArguments, Danu::UserCreator::objectId>' ../../../library/DanuModelObjectsFactory/UserCreatorFunction.cpp:40:83: instantiated from here /usr/include/boost/fusion/iterator/key_of.hpp:38:9: error: invalid use of incomplete type 'struct boost::fusion::extension::key_of_impl<boost::fusion::non_fusion_tag>' /usr/include/boost/fusion/iterator/key_of.hpp:20:16: error: declaration of 'struct boost::fusion::extension::key_of_impl<boost::fusion::non_fusion_tag>' Snippets of relevant code (hopefully enough): - the first snipped is how I declare the boost::fusion::map - the second is how I use and where the error is (<--!!!!!!!!) ... namespace UserCreator { struct objectId; struct userId; struct userName; typedef boost::fusion::map < boost::fusion::pair< objectId, ObjectId >, boost::fusion::pair< userId, int >, boost::fusion::pair< userName, std::string > > UserArgs; struct UserCreationArguments : public MOCFunctionParameter, public UserArgs ... ... ModelObject* UserCreatorFunction::createObject( const MOCFunctionParameter* aMOCFunctionParameter /* = NULL */) const { ... if ( (arguments = dynamic_cast< UserCreator::UserCreationArguments* >(const_cast<MOCFunctionParameter*>(aMOCFunctionParameter))) ) { ObjectId& objectId = boost::fusion::at_key< UserCreator::objectId >(*arguments); <--!!!!!!!! int& userId = boost::fusion::at_key< UserCreator::userId >(*arguments); std::string& userName = boost::fusion::at_key< UserCreator::userName >(*arguments); ... TIA -- Met vriendelijke groeten, Joost Kraaijeveld Askesis B.V. Molukkenstraat 14 6524NB Nijmegen tel: 024-3888063 / 06-51855277 fax: 024-3608416 web: www.askesis.nl

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Boost.Test with Boost.Thread
by Satish Kaveti 06 Mar '11

06 Mar '11

I am learning to create simple unit tests using Boost.Test. I am getting the following error when I run bjam. C:/DevTools/boost_1_44_0/tools/build/v2/build\feature.jam:138: in feature.feature from module feature error: feature already defined: error: in feature declaration: error: feature "threadapi" : "pthread" "win32" : "propagated" c:\DevTools\boost_1_44_0\libs\thread\build\Jamfile.v2:57: in modules.load from module Jamfile</c:/devtools/boost_1_44_0/libs/thread/build> C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:310: in load-jamfile from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:62: in project.load from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:760: in project.use from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:89: in load-used-projects from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:73: in load from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:115: in load-parent from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:458: in initialize from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:300: in load-jamfile from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:62: in load from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:168: in project.find from module project C:/DevTools/boost_1_44_0/tools/build/v2\build-system.jam:569: in load from module build-system C:\DevTools\boost_1_44_0\tools\build\v2/kernel\modules.jam:283: in import from module modules C:\DevTools\boost_1_44_0\tools\build\v2\kernel\bootstrap.jam:142: in boost-build from module C:\DevTools\boost_1_44_0\boost-build.jam:17: in module scope from module My Jamroot file is shown below : ------------------------------------- import os ; import testing ; use-project /blues/system : c:/devtools/boost_1_44_0/libs/system/build ; use-project /blues/thread : c:/devtools/boost_1_44_0/libs/thread/build ; use-project /blues/test : c:/devtools/boost_1_44_0/libs/test/build ; project : : requirements <threading>multi <link>static <include>c:/devtools/boost_1_44_0 <define>_WIN32_WINNT=0x0501 <define>_CRT_SECURE_NO_WARNINGS=1 <define>_SCL_SECURE_NO_WARNINGS=1 ; and my Jamfile is shown below : ------------------------------------- alias unit_test_framework : # Sources /blues/test//boost_unit_test_framework ; explicit unit_test_framework ; run-fail unit_test_example_01.cpp unit_test_framework ; How can I successfully build the unit test ? Thanks.

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[foreach] gcc 4.5 & 4.6 compiler error with BOOST_FOREACH(auto&& ...) loop
by Nathan Ridge 05 Mar '11

05 Mar '11

Hello, The following code fails to compile with gcc 4.5 or 4.6: #include <boost/foreach.hpp> template <typename> void f() { int A[6]; BOOST_FOREACH(auto&& x, A) ; } void g() { f<int>(); } The error is: test.cpp: In function 'void f() [with <template-parameter-1-1> = int]': test.cpp:14:12: instantiated from here test.cpp:6:5: error: invalid initialization of reference of type 'int&&' from expression of type 'int' Interestingly, the error goes away if I make f() a non-template function. It also compiles fine with gcc 4.4. The native range-based for version, however, compiles fine with gcc 4.6 (which is the only version to support it): #include <boost/foreach.hpp> template <typename> void f() { int A[6]; for(auto&& x : A) ; } void g() { f<int>(); } What is going on here? Is this a Boost issue or a gcc issue? Thanks, Nate.

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Re: [Boost-users] Threading a Shared Model with pointers
by pcunite＠fsmail.net 05 Mar '11

05 Mar '11

I explained this wrong. What is really happening is that each thread has a pointer to the object (forget about the vector for the moment) and it uses this as a key many hours later. When it is given serialized access to the "model/database cache", the thread wants to do work using that key, of course now it is no longer valid. This is why using map works, but I did not want to search every time, that is why weak_ptr works. Just wanted to know the best approach for this type of problem. All access to everything is thread safe. Any thoughts now?

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newbie: installation question
by Gunnar Salentin 05 Mar '11

05 Mar '11

Hi folks I just started with boost and have run into the first problem: the example program (see http://www.boost.org/doc/libs/1_46_0/more/getting_started/unix-variants.html) does not run though everything should be in place: The error is 'example.cpp:1:35: error: boost/lambda/lambda.hpp: No such file or directory" yes, I did check my file structure (see attached extract from Terminal). Installation of boost was done via sudo port... Anyone an idea what the issue might be? Thx GS User:~ SUserHG$ ls Desktop Downloads Library Music Public QuantLib-1.0.1.tar.gz example.cpp Documents Install-QuantLib.txt Movies Pictures QuantLib-1.0.1 Sites SUser:~ SUserHG$ cd /opt/local/include/boost/lambda SUser:lambda SUserHG$ ls algorithm.hpp casts.hpp construct.hpp core.hpp exceptions.hpp lambda.hpp numeric.hpp bind.hpp closures.hpp control_structures.hpp detail if.hpp loops.hpp switch.hpp SUser:lambda SUserHG$ cd SUser:~ SUserHG$ c++ -I /opt/local/include/boost example.cpp -o example example.cpp:1:35: error: boost/lambda/lambda.hpp: No such file or directory example.cpp: In function ‘int main()’: example.cpp:8: error: ‘boost’ has not been declared example.cpp:8: error: ‘lambda’ is not a namespace-name example.cpp:8: error: expected namespace-name before ‘;’ token example.cpp:12: error: ‘_1’ was not declared in this scope

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Threading a Shared Model with pointers
by pcunite＠fsmail.net 04 Mar '11

04 Mar '11

Threading a Shared Model with pointers I have a vector of pointers to objects created with new. Multiple threads access this vector in a safe manner with get/set. However, a thread may delete one of the objects, in which case another thread's pointer to the object is no longer valid. How can a method know if the pointer is valid? I have to examples that work and would like your thoughts. Test for pointer validity: 1. Use integers instead of pointers. A hash (std::map) checks to see if the pointer is still valid. Public methods look like get(size_t iKey), etc. Insde the method it does: if((it = mMap.find(iKey)) != mMap.end()) { TMyType * pMyType = it->second; // do something with know good pointer. } 2. Have a vector of shared_ptr. Each thread tries to call lock() on its weak_ptr. If the returned shared_ptr is null we know someone deleted it while we were waiting. Public methods look like get(boost::weak_ptr<TMyType> pMyType), etc. Insde the method it does: boost::shared_ptr<TMyType> pGOOD = pMyType.lock(); if (pGOOD == NULL) { // null, bad pointer do something return; } 3. Test for null on plain raw pointers? Is this possible? Public methods look like get(TMyType * pMyType), etc. Option 1 and 2 actually seem to work well. I don't know how they will scale. What is the best approach? Is there a portable version 3?

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[general] mingw.org site was hacked
by Jim Bell 04 Mar '11

04 Mar '11

Of interest to MinGW users: It seems that the mingw.org site was hacked a couple days ago: <http://sourceforge.net/mailarchive/message.php?msg_id=27147169>

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Boost Concepts with iterators and ranges
by Robert Ramey 04 Mar '11

04 Mar '11

I've been experimenting with Boost Concepts in conjunction with Boost Range and by implication boost iterators. I have a few questions from the documentation: a) I see BOOST_CONCEPT_USAGE described in some detail in the section Creating Concept Checking Classes. But in the section titled "Reference" I only find in the subsection "macros" BOOST_CONCEPT_ASSERT and BOOST_CONCEPT_REQUIRES. Is BOOST_CONCEPT_USAGE meant to be used? b) "Deprecated Concept Checking Classes" "For each of the concepts documented here, the library includes an identical concept checking class whose name ends in "Concept" For example, in addition to RandomAccessIterator, the library defines a RandomAccessIteratorConcept class template." It sounds like this means that I shouldn't expect to find "WritableIteratorConcept" but in fact in "interator_concepts.hpp" find just that. I'm assuming that's an oversight. c) except for the above, the Range library uses things like ForwardTraversal and ForwardTraversalConcept the iterators library uses ForwardTraversal only. d) the iterators concepts are in the root namespace boost_concepts while the range concepts are in the root namespace boost. e) boost/range/concepts.hpp includes the file boost/iterator/iterator_concepts.hpp All this makes it very hard to keep all this straight in one's head. Is there any possibility that all this could be made simpler to follow by some combination of documentation improvements and/or namespace coordination? Robert Ramey

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[program_options] escaping literal hash symbol for parse_config_file
by Rhys Ulerich 04 Mar '11

04 Mar '11

Hi all, With boost::program_options::parse_config_file, is there any way to escape a literal hash symbol ('#')? I want to set std::string-based option 'foo' to contain the var 'bar#baz', but the sensible-seeming foo=bar\#baz fails in that 'foo' only contains 'bar'. Other variants on quoting and escaping also fail. The source for common_config_file_iterator::get() in config_file.cpp seems to indicate this isn't possible. Can anyone confirm or deny that? Thanks, Rhys

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[boost::property_tree] rapidxml get_index bug for UTF8 ?
by 乔志强 04 Mar '11

04 Mar '11

When use UTF8, non ASCII char is > 127, but char is signed, So get_index() return a big value. char c = -120; get_index(c) VC2010 say: boost::property_tree::detail::rapidxml::internal::get_index<char> returned 4294967168 unsigned int then internal::lookup_tables<0>::lookup_whitespace[internal::get_index(ch)] is error. My patch: inline size_t get_index(const Ch c) { // *** char c (ASCII / UTF8) and wchar_t c: 0 ~ 127 is ASCII char size_t r = c; //******** convert to unsigned // If not ASCII char, its sematic is same as plain 'z' // if (c > 255) //********* ASSCII is 0 to 127 if (r > 127) //******** check r, or check if(c < 0 || c > 127) { return 'z'; } return r; //******** return r } This is boost code: boost_1_46_0\boost\property_tree\detail\rapidxml.hpp template<class Ch> inline size_t get_index(const Ch c) { // If not ASCII char, its sematic is same as plain 'z' if (c > 255) { return 'z'; } return c; } // Detect whitespace character struct whitespace_pred { static unsigned char test(Ch ch) { return internal::lookup_tables<0>::lookup_whitespace[internal::get_index(ch)]; } }; // Detect node name character struct node_name_pred { static unsigned char test(Ch ch) { return internal::lookup_tables<0>::lookup_node_name[internal::get_index(ch)]; } };

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[boost::property_tree] info_parser_read assert in vs2010 when use UTF8
by 乔志强 04 Mar '11

04 Mar '11

When use UTF8, non ASCII char is > 127, but char is signed, So if the value > 127, the char c is < 0, (unsigned)(c + 1) is a big value, read_info() assert in vs2010 when use UTF8 in debug build. std::isspace() call extern "C" int __cdecl _chvalidator( int c, int mask ) { _ASSERTE((unsigned)(c + 1) <= 256); return _chvalidator_l(NULL, c, mask); } My patch is us my_isspace(): template<class Ch> bool my_isspace(const Ch c) { if(c >= 0 && c <= 127) { return isspace(c); } return false; } boost_1_46_0\boost\property_tree\detail\info_parser_read.hpp // Advance pointer past whitespace template<class Ch> void skip_whitespace(const Ch *&text) { using namespace std; while (isspace(*text)) ++text; } // Extract word (whitespace delimited) and advance pointer accordingly template<class Ch> std::basic_string<Ch> read_word(const Ch *&text) { using namespace std; skip_whitespace(text); const Ch *start = text; while (!isspace(*text) && *text != Ch(';') && *text != Ch('\0')) ++text; return expand_escapes(start, text); }

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[uBLAS] Matrix inversion
by Ryan 03 Mar '11

03 Mar '11

I haven't found anywhere in the documentation for a method that does matrix inversion. Does such a method exist but isn't well documented? Ryan

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Re: [Boost-users] [MSM] test if state machine is in a given state /const get_state
by Christophe Henry 03 Mar '11

03 Mar '11

> I considered to use the concept of flags, but then rejected it, simply > because it adds another layer of abstraction, which is great in certain > cases, but also increases the overall complexity. > > In my case i need hardly any properties which span over more than one > state, so i prefer to keep thinks simple for now. It's the constant > struggle to have enough, but not to much abstraction... > > But thanks for the hint, i'll keep that in mind. Hmmm as you can provide every state with a specific tag, I don't see why to develop a less generic, less efficient concept which will be hard to make work for submachines. Am I missing something? >>> 2) Is a const version of "get_state" possible ? And how? >> >> Sure. My mistake. Will be fixed in 1.47. Would you mind opening a >> ticket so I don't forget it? > > done, ticket #5253. Now i'am looking forward to 1.47 ;-) Thanks. Regards, Christophe

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phoenix vs. python
by Neal Becker 03 Mar '11

03 Mar '11

Can I use phoenix lambda in boost::python? Let's see: ------------------------------------ #include <boost/python/module.hpp> #include <boost/python/def.hpp> #include <boost/spirit/home/phoenix.hpp> namespace bp=boost::python; BOOST_PYTHON_MODULE (test_phoenix) { bp::def ("test1", &boost::phoenix::val(1)); } ---------------------------------------- Any suggestions? Here's what gcc-4.5 says: In file included from test_phoenix.cc:2:0: /usr/local/src/boost_1_46_0.hg/boost/python/def.hpp: In function ‘void boost::python::def(const char*, Fn) [with Fn = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::reference_eval, boost::fusion::vector<boost::phoenix::value<int>, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >]’: test_phoenix.cc:8:44: instantiated from here /usr/local/src/boost_1_46_0.hg/boost/python/def.hpp:91:5: error: cannot pass objects of non-trivially-copyable type ‘struct boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::reference_eval, boost::fusion::vector<boost::phoenix::composite<boost::phoenix::reference_eval, boost::fusion::vector<boost::phoenix::value<int>, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> >, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >’ through ‘...’ In file included from /usr/local/src/boost_1_46_0.hg/boost/python/def.hpp:11:0, from test_phoenix.cc:2: /usr/local/src/boost_1_46_0.hg/boost/python/make_function.hpp: In function ‘boost::python::api::object boost::python::make_function(F) [with F = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::reference_eval, boost::fusion::vector<boost::phoenix::value<int>, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >]’: /usr/local/src/boost_1_46_0.hg/boost/python/def.hpp:82:61: instantiated from ‘boost::python::api::object boost::python::detail::make_function1(T, ...) [with T = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::reference_eval, boost::fusion::vector<boost::phoenix::value<int>, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >]’ /usr/local/src/boost_1_46_0.hg/boost/python/def.hpp:91:5: instantiated from ‘void boost::python::def(const char*, Fn) [with Fn = boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::reference_eval, boost::fusion::vector<boost::phoenix::value<int>, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >]’ test_phoenix.cc:8:44: instantiated from here /usr/local/src/boost_1_46_0.hg/boost/python/make_function.hpp:104:60: error: no matching function for call to ‘get_signature(boost::phoenix::actor<boost::phoenix::composite<boost::phoenix::reference_eval, boost::fusion::vector<boost::phoenix::value<int>, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_, boost::fusion::void_> > >&)’

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Async_accept
by Marco Piacentini 03 Mar '11

03 Mar '11

Hi guys... Reading docs, I understand that acceptor.async_accept(), accept a connection and immediately return, so the acceptor can accept another concurrent connection request...and in the meanwhile the handler can process the request...it's right? I need to make a server that listen connection requests, and create a separate process (child) to handle each of them, so it can be still waiting a new connection. The classic MultiProcess Server. Can I do this simply using the async_accept, without create new process?or I'm missing something? Thanks...

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Re: [Boost-users] [MSM] test if state machine is in a given state /const get_state
by Christophe Henry 03 Mar '11

03 Mar '11

Hi Jan, > i am working with the Boost 1.45 Meta State Machine, using both > orthogonal regions and submachines. Overall, i am very happy with this > library. Cool :) > But i am looking for a nice way to check if a state machine (e.g. > instance mAvail of class AvailFSM) is in a given state, for example i > would like to write something like this: > > assert(isInState(mAvail, AvailFSM::UpstreamAvailable())); > > I didn't find something like "isInState" provided by the MSM library, so > i came up with the following implementation: > > template <class FSM, class StateType> > bool isInState(const FSM& p, const StateType& s) > { > int stateId = boost::msm::back::get_state_id<typename > FSM::stt,StateType>::value; > > for (int i=0; i < FSM::nr_regions::value; ++i) > { > if(p.current_state()[i] == stateId) > { > return true; > } > } > return false; > } > > This works well for simple state machines and orthogonal regions, but > not for submachines. Does any one knows a way to extend the above code > to work with submachines? Hmmm not a bad idea indeed, I need to think about it, but in the meantime I have another (and I think faster) solution. See below. <snip> > Currently i am using the following workaround: > > assert(isInState(mAvail, AvailFSM::UpstreamAvailable())); > assert(isInState(mAvail.get_state<AvailFSM::UpstreamAvailable&>(), > AvailFSM::UpstreamAvailable::Primary())); > > I consider this solution ugly not only because of its lengthiness, but > also because "get_state" isn't a const function. Unfortunately i'am not > deep enough into the template magic to tell if a const implementation of > "get_state" is possible. Can anyone help me out ? Usually, if you want to ask "isInState", you actually mean "is my fsm in such a state that a property is true?". Next, what you will want is: assert(isInState(mAvail, AvailFSM::UpstreamAvailable()) || isInState(...) && !... ); And this can pretty fast get much uglier as you need more and more conditions. To that aim, MSM offers the concept of flags, allowing you to flag a state with a certain property. You can then check if the property is true with, say: if (mAvail.is_flag_active<UpstreamOk>()) ... Please have a look at (for 1.46 but any released version of MSM can do this): http://www.boost.org/doc/libs/1_46_0/libs/msm/doc/HTML/ch03s02.html#d0e1110 Ah and it also works on submachines. > So, to sum up, i have two questions: > 1) How to implement something like "isInState" that even works on > submachines, if possible ? Would the offered solution satisfy your need? > 2) Is a const version of "get_state" possible ? And how? Sure. My mistake. Will be fixed in 1.47. Would you mind opening a ticket so I don't forget it? > best regards, > jan Best regards, Christophe

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[phoenix][v3] Evaluating a terminal expression in the custom actions class.
by Alexander Ospin 03 Mar '11

03 Mar '11

Is it possible to evaluate terminal and custom_terminal expressions in the some custom actions class? For instance how to implement "terminal_eval" to print something in the following code? #include <boost/phoenix/phoenix.hpp> #include <iostream> using namespace boost; struct actions { template <typename Rule, typename Dummy = void> struct when; }; template <> struct actions::when<phoenix::rule::terminal> : phoenix::call<terminal_eval> {}; int main() { int var = 11; phoenix::eval(phoenix::val(var), phoenix::context(int(), actions())); return 0; } I've tried to use the following form, but encountered some compiler errors: (GCC-4.2.1[FreeBSD], boost and phoenix were taken from SVN, latest versions) struct terminal_eval { typedef void result_type; template <typename Context, typename Expr> result_type operator ()(Context const &ctx, Expr const &expr) { std::cout << "terminal" << std::endl; } }; ../../../../boost.phoenix/boost/phoenix/core/call.hpp:32: error: invalid use of incomplete type 'struct boost::phoenix::detail::call_impl<terminal_eval, const boost::phoenix::actor<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int>, 0l> >&, const int&, const actions&, 0l>' ../../../../boost.phoenix/boost/phoenix/core/call.hpp:22: error: declaration of 'struct boost::phoenix::detail::call_impl<terminal_eval, const boost::phoenix::actor<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int>, 0l> >&, const int&, const actions&, 0l>' ../../../../boost/boost/proto/transform/call.hpp:315: error: no type named 'result_type' in 'struct boost::proto::switch_<boost::phoenix::meta_grammar>::impl<const boost::phoenix::actor<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int>, 0l> >&, const int&, const actions&>' ../../../../boost/boost/proto/transform/call.hpp:320: error: no type named 'result_type' in 'struct boost::proto::switch_<boost::phoenix::meta_grammar>::impl<const boost::phoenix::actor<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<int>, 0l> >&, const int&, const actions&>' The same situation with the phoenix::ref and custom_terminal rule.

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[date_time] Concurrent posix_time streaming crashes under MinGW-32
by Jim Bell 03 Mar '11

03 Mar '11

The attached program crashes under MinGW-32 (gcc-4.4), but works under VC8. It does concurrent streaming of posix_time::ptime values to a std::ostringstream. Mutexing the ostringstream from construction to destruction keeps it from crashing, but that shouldn't have to be done for independent streams. Mutexing just the ptime insertions makes it run longer, but it still crashes. I'm posting it here instead of taking it straight to Trac to see if anyone has input. Could it be related to <https://svn.boost.org/trac/boost/ticket/3961> or <https://svn.boost.org/trac/boost/ticket/3369>? Building: MinGW: g++ -DBOOST_THREAD_USE_LIB DTConcur.cpp -IC:\Software\Open\lib\boost_1_45_0\ -DWIN32 -D_WINDOWS -LC:\Software\Open\lib\boost_1_45_0\mgw44\lib -mthreads -g -frtti -fexceptions -mthreads -Wall -lstdc++ -lmingw32 -o DTConcur -lboost_thread-mgw44-mt-s-1_45 VC8: cl DTConcur.cpp /IC:\Software\Open\lib\boost_1_45_0\ /MT /D BOOST_THREAD_USE_LIB /GR /EHsc /D "WIN32" /D "_WINDOWS" /FeDTConcur.exe /link /LIBPATH:C:\Software\Open\lib\boost_1_45_0\msvc8\lib

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[preprocessor] have macro do different things based on structure of its argument
by Nathan Ridge 03 Mar '11

03 Mar '11

Hello, I would like to write a macro MY_MACRO(x) that does different things based on the structure of its input, e.g. something different for each of the following forms: MY_MACRO(x) // a single token MY_MACRO((x, y)) // a parenthesized list of two tokens MY_MACRO((x, y, z)) // a parenthesized list of three tokens MY_MACRO(x y) // two tokens MY_MACRO(x y z) // three tokens MY_MACRO(x = y) // three tokens with the second one being something specific Are any of these possible? Thanks, Nate.

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ASIO / IO Completion Ports (Windows)
by asif saeed 02 Mar '11

02 Mar '11

Hi, I wonder if ASIO on Windows also implements IO Completion ports. I think this is called Proactor, right? I would be thankful if you point me to the right direction. Also, any links/examples of using ASIO with Boost::Thread (or TR1) would be very helpful. I am a newbie on ASIO & Boost Thread. Sincerely / Asif

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Re: [Boost-users] [GIL] gray pixel iterator in generic algorithm
by Robert Lupton the Good 02 Mar '11

02 Mar '11

> With this, the unit test for my gray opening function with an unscaled float image now compiles and works fine. Does this mean that you have some clean way to handle gil images that don't automatically scale into [0,1]? If so, can we have it pushed into the next boost release? I have a clunky version of this that I'm not proud of, but I certainly need. I'm an astronomer, and the values in my images (unsigned short, int, float) are directly related to the number of photons detected so scaling is a real problem. R

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