- Boost-users - lists.boost.org

[variant] apply templated visitor
by Dmitry Vinogradov 20 May '09

20 May '09

Imagine the following: struct foo { bar& operator[](int); bar& operator[](std::string); } Foo; boost::variant<int, std::string> Idx; Is some simple way exist to apply foo::operator[](T) for Foo and Idx? Something like boost::apply_visitor(boost::bind(&foo::operator[], boost::ref(Foo), _1), Idx); // does not compile

2 1

find the largest/most precise of two types
by Alex Flint 20 May '09

20 May '09

Hi there, I have a bunch of functions that accept two numeric arguments. In the case that the types of these arguments are different I want to figure out what the return type should be. The rule I would like to use is that the largest of the two types should be used for internal computations and the return type. f(someFloat, someDouble) -> double f(someFloat, someFloat) -> float f(someInt, someFloat) -> float Is there a way I can do this, perhaps with boost's type_traits? Cheers, Alex

5 4

Error (runtime) assigning multi_array to multi_array with smaller dimensions
by Matheus Araújo Aguiar 20 May '09

20 May '09

Hello everyone, I'm getting an error when trying to get one sub array from a multi_array with 2 dimensions. This is the code: //at class constructor boost::multi_array<char, 2> array2d = new boost::multi_array<char, 2>(boost::extents[x][y]); ... //at class method boost::multi_array<char, 1> array1d = array2d[0]; And the error i got: Reference boost::detail::multi_array::value_accessor_n<T, NumDims>::access(boost::type<Reference>, boost::multi_array_types::index, TPtr, const boost::multi_array_types::size_type*, const boost::multi_array_types::index*, const boost::multi_array_types::index*) const [with Reference = boost::detail::multi_array::sub_array<char, 1u>, TPtr = char*, T = char, unsigned int NumDims = 2u]: Assertion `size_type(idx - index_bases[0]) < extents[0]' failed. Could anyone help, please? Thanx, -- Matheus Araújo Aguiar Computer Scientist matheus.pit(a)gmail.com

2 2

To find adjacent vertices using Boost Graph....
by Amanullah Yasin 20 May '09

20 May '09

Hi, Dear All, In the graph of nodes (e.g. 1 , 2, 3, 4, 5, 6 , 7........). I want to iterate to the adjacent nodes of node x. For this i am using adjacent_vertices(v, g), which returns std::pair<adjacency_iterator, adjacency_iterator> for (i = 1; i <= n; i++){ tie(eo, eo_end) = adjacent_vertices( vertex( i-1, graph), graph); } Please guide me how i can use the adjacency_iterator to access the neighbourhood of node x ? e.g. graph is a 1 ---- 2 3 4 5 2 ---- 4 5 6 3 ---- 5 6 7 so, neighbourhood of 1 are 2 3 4 5 2 are 4 5 6 3 are 5 6 7 I will be thankful to you. Regards Amanullah YASIN Master2 (ECD) Ecole Polytechnique Université de Nantes, France. Mob# 06 47 62 89 96 Fix # 02 72 00 26 45 amanyasin(a)gmail.com

1 0

[interprocess] Mutex Query
by Rick Way 20 May '09

20 May '09

I want to make sure that when my program exits ungracefully (CTRL-C, seg fault, etc) it releases a Boost.Interprocess named_upgradable_mutex, if it's holding it. I've created a signal handler to catch these ungraceful exits. Is there any way to tell if my process currently holds an exclusive or sharable lock on the mutex? I've tried blindly calling mutex.unlock() and mutex.unlock_sharable() but that seems to permanently lock the mutex when the shareable lock is set. RickW

2 1

[test] Ignoring SIGCHLD for signal codes other than CLD_EXITED
by Gevorg Voskanyan 20 May '09

20 May '09

I could not find a response to the following message: http://lists.boost.org/boost-users/2008/09/40618.php , which proposes to modify ignore_sigchild() implementation to account for a proposed BOOST_TEST_IGNORE_SIGCHLD preprocessor switch. I am seconding this request. Has it ever been considered? Or was it the message simply went unnoticed? Thanks, Gevorg

3 10

failure of VertexListGraphConcept check
by Christian Bähnisch 20 May '09

20 May '09

Hello, Trying to write an BGL adaption of a BGL foreign graph-class I followed the conversion guide: "http://www.boost.org/doc/libs/1_39_0/libs/graph/doc//leda_conversion.html" Using "boost::function_requires<boost::VertexListGraphConcept<MyGraph> >();" in order to check my implemetation gcc complains about: "boost/graph/graph_concepts.hpp:199: error: no matching function for call to 'vertices(const MyGraph&)'" I further noticed that the test-case "stanford_graph_cc.cpp" found in "BOOST/libs/graph/test" also fails with this error. Any help would be much appreciated! greetings, Chris

1 0

Re: [Boost-users] [Regex] Source-only link error in MSVC
by dtexg＠hush.com 20 May '09

20 May '09

On Tue, 19 May 2009 03:42:57 -0500 John Maddock <john(a)johnmaddock.co.uk> wrote: >> [...] >> error LNK2019: unresolved external symbol >> [...] >> (?do_assign@?$basic_regex@DU?$regex_traits@DV?$ >> w32_regex_traits@D@boost@@@boost@@@boost@@ >> AAEAAV12@PBD0I@Z) referenced >> [...] >> (?assign@?$basic_regex@DU?$regex_traits@DV?$ >> w32_regex_traits@D@boost@@@boost@@@boost@@ >> QAEAAV12@PBD0I@Z) >> [...] >> I wrote the following code: >> >> #define BOOST_REGEX_SOURCE >> #include <boost/regex.hpp> >> >> int main() >> { >> boost::regex r("a"); >> return 0; >> } >> >> Everything compiles, but linking fails with the above error. >> [...] >> >> In a post from 2006, John wrote, "if you are doing something, >> umm, strange, and you can't track down the cause of the error, >> you can always just add the regex source directly to your >> application," but I've not seen this successfully demonstrated >> in Visual C++. I'm just looking for an absolutely parsimonious >> way to add Boost Regex to a VC++ project. > >Well, you need to do what I said, not what you did ;-) > >Take all the .cpp files in libs/regex/src and add them to your >console project's source, build and voila, it should all work. > >BTW use BOOST_REGEX_NO_LIB not BOOST_REGEX_SOURCE in your source >files, as the latter is for private regex use only and most >certainly does not do what you think it does. > >In point of fact I do this all the time, so it definitely does >work. > >HTH, John. My embarrassment is outstripped only by my gratitude. That did help completely, so I just want to confirm it for indexing and posterity: I changed the #define BOOST_REGEX_SOURCE to BOOST_REGEX_NO_LIB (or BOOST_ALL_NO_LIB) instead, then right- clicked on Source Files, chose Add -> Existing Item, and added all the .cpp files in libs/regex/source. When I built, it compiled all those .cpp files (where obviously it wasn't before), then linked successfully and everything just worked and everyone lived happily ever after. Sadly, I never would have figured that out. Thank you very much! /Eric -- Wanna lose weight? Weight Loss Programs that work. Click here. http://tagline.hushmail.com/fc/BLSrjkqbR3flkqN6HzqHIZfbT5vIrA1g60gAsnOhshGi…

2 1

[zip_iterator] Which header files?
by Robert Jones 20 May '09

20 May '09

The iterators documentation seems a bit thin! Does it say anywhere which header files are required to use zip_itrerators? Also, is the use of zip_itertor and others still very much current practise, or are there other techniques which tend to be used instead? Thanks, Rob.

1 0

[boost 1.39][Serialization] BOOST_CLASS_EXPORT_GUID macro failed to compile with C2888 error under MSVS.
by Vitaly Dolya 20 May '09

20 May '09

Hi, All! Since I had no answer on my previous post, I'll try to clarify the problem here. So, I use a macro BOOST_CLASS_EXPORT_GUID from Boost.Serialization library. And everything was just fine until boost 1.39 came up to stage recently. Now the same very of my code, I've been using for so long (starting with boost 1.35 I guess), failed to compile under MS Visual Studio 2008 SP1. Compiler gives me an error error C2888: 'boost::archive::detail::`anonymous-namespace'::init_guid<CSomeClass>' : symbol cannot be defined within namespace 'anonymous-namespace'. The error occurs when export.hpp file (contains BOOST_CLASS_EXPORT_GUID) is included to stdafx.h (to precompiled headers) and the macro is used in any other cpp-file. I guess the problem is that 'init_guid' structure declaration (declared inside anonymous namespace) and definition appear in different translation units. So, it looks like there is a bug in boost 1.39 to me. Am I right? And what should I do? Should I file a bug? Thanks in advance.

2 6