November 2005 - Boost-users

[boost][lambda] additional placeholders
by Noel Belcourt 06 Dec '05

06 Dec '05

HI, I'm trying to extend the number of placeholders in boost lambda 1.33.0. There are three available by default and I need at least one more (_4) . I've followed the pattern establish for _3 to define _4, modifying the following files along the way. // lambda/core.hpp boost::lambda::placeholder3_type free3 = boost::lambda::placeholder3_type(); boost::lambda::placeholder4_type free4 = boost::lambda::placeholder4_type(); boost::lambda::placeholder3_type& _3 = free3; boost::lambda::placeholder4_type& _4 = free4; // lambda/detail/lambda_functors.hpp template<> struct placeholder<FOURTH> { template<class SigArgs> struct sig { typedef typename detail::get_element_or_null_type<3, SigArgs>::type type; }; template<class RET, CALL_TEMPLATE_ARGS> RET call(CALL_FORMAL_ARGS) const { CALL_USE_ARGS; return c; } }; typedef const lambda_functor<placeholder<THIRD> > placeholder3_type; typedef const lambda_functor<placeholder<FOURTH> > placeholder4_type; // lambda/detail/arity_code.hpp enum { NONE = 0x00, // Notice we are using bits as flags here. FIRST = 0x01, SECOND = 0x02, THIRD = 0x04, FOURTH = 0x08, EXCEPTION = 0x10, RETHROW = 0x20}; So now _4 is defined but I get compilation errors from boost/function/function_template.hpp when I attempt to use _4. Is there some change necessary to either lambda placeholders or to boost function to get it to work correctly? Thanks, -- Noel Belcourt // With the changes above, this code fails with the message below. #include <boost/function.hpp> #include <boost/lambda/bind.hpp> using namespace boost; using namespace boost::lambda; typedef function<void (int, int, double, double)> func_t; template <class T1, class T2, class T3, class T4> struct A { template <class R> A(void (R::*required)(T1, T2, T3, T4), R *r) : u(bind(required, r, _1, _2, _3, _4)) {} func_t u; }; struct B { void f(int, int, double, double); }; int main(int, char *[]) { B b; A<int, int, double, double> a(&B::f, &b); return 0; } This is the error message from CW 9.6 on Darwin Error : call of non-function (point of instantiation: 'main(int, char **)') (instantiating: 'A<int, int, double, double>::A<B>(void (B::*)(int, double, double), B *)') (instantiating: 'boost::function4<void, int, int, double, double, std::allocator<void>>::function4 `base constructor'<boost::lambda::lambda_functor<boost::lambda:: lambda_functor_base<boost::lambda::action<6, boost::lambda::function_action<6, boost::lambda::detail::unspecified>>, boost::tuples::tuple<void (B::*const )(int, double, double), B *const , const boost::lambda::lambda_functor<boost::lambda::placeholder<1>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<2>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<4>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<8>>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>>>>(boost::lambda::lambda_functor<boost:: lambda::lambda_functor_base<boost::lambda::action<6, boost::lambda::function_action<6, boost::lambda::detail::unspecified>>, boost::tuples::tuple<void (B::*const )(int, double, double), B *const , const boost::lambda::lambda_functor<boost::lambda::placeholder<1>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<2>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<4>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<8>>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>>>, int)') (instantiating: 'boost::function4<void, int, int, double, double, std::allocator<void>>::assign_to<boost::lambda::lambda_functor<boost:: lambda::lambda_functor_base<boost::lambda::action<6, boost::lambda::function_action<6, boost::lambda::detail::unspecified>>, boost::tuples::tuple<void (B::*const )(int, double, double), B *const , const boost::lambda::lambda_functor<boost::lambda::placeholder<1>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<2>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<4>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<8>>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>>>>(boost::lambda::lambda_functor<boost:: lambda::lambda_functor_base<boost::lambda::action<6, boost::lambda::function_action<6, boost::lambda::detail::unspecified>>, boost::tuples::tuple<void (B::*const )(int, double, double), B *const , const boost::lambda::lambda_functor<boost::lambda::placeholder<1>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<2>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<4>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<8>>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>>>)') (instantiating: 'boost::function4<void, int, int, double, double, std::allocator<void>>::assign_to<boost::lambda::lambda_functor<boost:: lambda::lambda_functor_base<boost::lambda::action<6, boost::lambda::function_action<6, boost::lambda::detail::unspecified>>, boost::tuples::tuple<void (B::*const )(int, double, double), B *const , const boost::lambda::lambda_functor<boost::lambda::placeholder<1>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<2>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<4>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<8>>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>>>>(boost::lambda::lambda_functor<boost:: lambda::lambda_functor_base<boost::lambda::action<6, boost::lambda::function_action<6, boost::lambda::detail::unspecified>>, boost::tuples::tuple<void (B::*const )(int, double, double), B *const , const boost::lambda::lambda_functor<boost::lambda::placeholder<1>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<2>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<4>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<8>>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>>>, boost::detail::function::function_obj_tag)') (instantiating: 'boost::detail::function::void_function_obj_invoker4<boost::lambda:: lambda_functor<boost::lambda::lambda_functor_base<boost::lambda:: action<6, boost::lambda::function_action<6, boost::lambda::detail::unspecified>>, boost::tuples::tuple<void (B::*const )(int, double, double), B *const , const boost::lambda::lambda_functor<boost::lambda::placeholder<1>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<2>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<4>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<8>>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>>>, void, int, int, double, double>::invoke(boost::detail::function::any_pointer, int, int, double, double)') function_template.hpp line 136 BOOST_FUNCTION_RETURN((*f)(BOOST_FUNCTION_ARGS)); Error : call of non-function (instantiating: 'boost::detail::function::void_function_obj_invoker4<boost::lambda:: lambda_functor<boost::lambda::lambda_functor_base<boost::lambda:: action<6, boost::lambda::function_action<6, boost::lambda::detail::unspecified>>, boost::tuples::tuple<void (B::*const )(int, double, double), B *const , const boost::lambda::lambda_functor<boost::lambda::placeholder<1>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<2>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<4>>, const boost::lambda::lambda_functor<boost::lambda::placeholder<8>>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>>>, void, int, int, double, double>::invoke(boost::detail::function::any_pointer, int, int, double, double)') function_template.hpp line 136 BOOST_FUNCTION_RETURN((*f)(BOOST_FUNCTION_ARGS));

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[wave] bug report for wave
by Andreas Sæbjørnsen 05 Dec '05

05 Dec '05

When preprocessing the code #define $jack int test; $jack using any preprocessor using the wave library, in this case the samples/lexed_tokens/lexed_tokens preprocessor , gives the following error: PP_DEFINE (#369) at test.C ( 1/ 1): >#define< SPACE (#393) at test.C ( 1/ 8): > < lexed_tokens: /home/saebjornsen1/projects/boost/boost/wave/token_ids.hpp:497: boost::wave::util::flex_string<char, std::char_traits<char>, std::allocator<char>, boost::wave::util::CowString<boost::wave::util::AllocatorStringStorage<char, std::allocator<char> >, char*> > boost::wave::get_token_name(boost::wave::token_id): Assertion `id < T_LAST_TOKEN-T_FIRST_TOKEN' failed. Aborted using the preprocesor cpp (from the gcc team) I get (as cpp test.C): # 1 "test.C" # 1 "<built-in>" # 1 "<command line>" # 1 "test.C" int test; I believe the problem lies in that the lexer does not recognize the '$' as a valid character within the name of macro definition. Thanks Andreas Saebjoernsen

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Wave library fails to compile with VC7.1 - Buffer overrun in cl.exe
by Didier Malenfant 04 Dec '05

04 Dec '05

It seems like this was fixed by turning off the rtti for VC7.1 and I verified that both V1 and V2 jamfiles have the workaround line in them (not sure which one is getting used as I'm not passing any parameters for that) C:\work\boost_1_33_1>..\boost-jam-3.1.11-1-ntx86\bjam.exe "-sTOOLS=vc-7_1-stlport" "-sSTLPORT_PATH=.." "-sBUILD=<native-wchar_t>on" ****************************************************** Building Boost.Iostreams with bzip2 support disabled. To enable bzip2, consult the Boost.Iostreams documentation ****************************************************** ****************************************************** Building Boost.Iostreams with zlib and gzip support disabled. To enable zlib and gzip, consult the Boost.Iostreams documentation ****************************************************** Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (and if you don't know what ICU is then you probably don't need it). ...found 11410 targets... ...updating 3 targets... vc-C++ bin\boost\libs\wave\build\libboost_wave.lib\vc-7_1-stlport\debug\native- wchar_t-on\threading-multi\instantiate_cpp_grammar.obj instantiate_cpp_grammar.cpp "cl" /Zm800 -nologo /EHsc -c -D_STLP_DEBUG=1 -D_STLP_DEBUG_UNINITIALIZED=1 -D_STLP_USE_DYNAMIC_LIB=1 /Z7 /Od /Ob0 /EHsc /GR /MDd /Op /wd4675 /Zc:forScope /Zc:wchar_t -I"bin\boost\libs\wave\build" -I"C:\work\boost_1_33_1" -I"..\STLport-4.6.2\stlport" -I"C:\work\boost_1_33_1" -Fo"bin\boost\libs\wave\build\libboost_wave.lib\vc-7_1-stlport\debug\nat ive-wchar_t-on\threading-multi\instantiate_cpp_grammar.obj" -Tp"C:\work\boost_1_33_1libs\wave\build\../src/instantiate_cpp_grammar.c pp" ...failed vc-C++ bin\boost\libs\wave\build\libboost_wave.lib\vc-7_1-stlport\debug\native- wchar_t-on\threading-multi\instantiate_cpp_grammar.obj... ...skipped <@boost!libs!wave!build\libboost_wave.lib\vc-7_1-stlport\debug\native-wc har_t-on\threading-multi>libboost_wave-vc71-mt-gdp-1_33_1.CMD for lack of <@boost!libs!wave!build\libboost_wave.lib\vc-7_1-stlport\debug\native-wc har_t-on\threading-multi>instantiate_cpp_grammar.obj... ...skipped <@boost!libs!wave!build\libboost_wave.lib\vc-7_1-stlport\debug\native-wc har_t-on\threading-multi>libboost_wave-vc71-mt-gdp-1_33_1.lib for lack of <@boost!libs!wave!build\libboost_wave.lib\vc-7_1-stlport\debug\native-wc har_t-on\threading-multi>instantiate_cpp_grammar.obj... ...failed updating 1 target... ...skipped 2 targets... I still get the buffer overrun in cl.exe. -D --- Didier 'Dids' Malenfant President Ready At Dawn Studios LLC www.readyatdawn.com <http://www.readyatdawn.com/>

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MingW bug
by Andre Tampubolon 02 Dec '05

02 Dec '05

This is my first Boost program #include <iostream> #include <cstdlib> #include <boost\random.hpp> using namespace std; using namespace boost; typedef boost::mt19937 BaseGenerator; typedef boost::uniform_real<double> Distribution; typedef boost::variate_generator<BaseGenerator,Distribution> Generator; double boostDoubleRand() { static BaseGenerator base; static Distribution dist; static Generator rng(base,dist); return rng(); } int main() { cout << "expect 5 numbers within the interval [0,1)" << endl; for (int i = 0; i < 5; i++) { cout << boostDoubleRand() << "\n"; } cout << endl; return 0; } Compiled using Borland C++ 5.6.4 and it works well. But when I compile it using MingW GCC, it only prints "expect 5 numbers within the interval [0,1)" and not the 5 random numbers. Why ? --------------------------------- Yahoo! FareChase - Search multiple travel sites in one click.

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[Test] BOOST_CHECK() -> unknown location(0) when an exception is thrown...
by Kevin Wheatley 01 Dec '05

01 Dec '05

Hi, I have a test where BOOST_CHECK() results in a call that causes an exception, but it gives no location, would it be possible to change the reporting code that catches the exception to report the file and line number to give me 1 click navigation to the site of the calling test? Perhaps the macro could force a check point or something and then log_exception could use that? I'm using BOOST_AUTO_TEST_MAIN as the driver for the tests with BOOST_AUTO_TEST_CASE "functions" Thanks Kevin -- | Kevin Wheatley, Cinesite (Europe) Ltd | Nobody thinks this | | Senior Technology | My employer for certain | | And Network Systems Architect | Not even myself |

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Looking for is_base_of
by Dave 01 Dec '05

01 Dec '05

Hello all, For the life of me, I cannot find is_base_of<>. What header files / namespaces do I need to reference to get at this little guy? Actually, I'm starting to think it has been replaced and that I should be looking for something else... Thanks, Dave

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[Boost.Format] empty string argument causes VC 8.0 to assert
by Mick Hollins 01 Dec '05

01 Dec '05

The following code causes a runtime assertion in VC 8.0: std::string l_param; std::string l_str = (boost::format("here is an empty string: %1%") % l_param).str(); It passes an empty string argument to boost::format. The assert is inside the implementation of basic_string::append() and boils down to the fact that the implementation of boost::format ends up calling basic_string::append(const char *, size_type) with a null pointer, which causes basic_string::append to assert. The following sample code causes the same assertion without boost::format being involved: std::string l_str; const char *l_null = NULL; std::string::size_type l_size = 0; l_str.append(l_null, l_size); // causes an assert I have currently disabled the assertion by calling the following code before I do anything else: #if _MSC_VER >= 1400 _CrtSetReportMode( _CRT_ASSERT, _CRTDBG_MODE_FILE); _CrtSetReportFile( _CRT_ASSERT, _CRTDBG_FILE_STDERR ); #endif which causes the asserts to simply emit a message to stderr rather than to pop up a message box, but I don't really want to disable VC 8.0's assertions across the board. My questions are: 1) Is this considered to be a bug in boost::format or a case of VC 8.0's runtime checks being overzealous? Personally I feel that calling append(null, 0) should be allowed and VC 8.0 is being too protective, but the copy of the C++ standard I have suggests that VC 8.0 is correct. 2) Either way, what do people think is the best way forward? thanks, mick

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The problem about shorthest path computation
by liu jianfei 01 Dec '05

01 Dec '05

Hi, all Recently, I faced a big problem when I'm using the boost function of shorthest path computing including dijkstra_shortest_paths and johnson_all_pairs_shortest_paths. My projectet was that I extracted all the surface voxels of a volume as the vertexs of the graph, and 26-connection between them as a edge. Hence, I got a large sparse graph which composed of 12768 vertexs and around 86000 edges. In the next stage, I implemented the dijkstra_shortest_paths computation for each vertex. However, it succeded in some points and failed in other points. If I changed the weight of each edge into 1, all points worked. If I used other weights for different edges, then problem poped up. Also, some points worked for this special weight, and failed for others. I think the shortest path algorithm should be unrelated with the weight assignment. Initially, I think something was wrong in my graph buliding. But when I wrote the shorthest path algorithm by myself and all points worked, I felt there may be a bug in dijkstra_shortest_paths class. If someone else faces the same problem, feel free to tell me. If not, I'm willing to paste my graph code in spite of its complexity. Thanks Regards!

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Compilation difference between intel 9.0 and msvc 7.1 regarding const
by Chris Goller 30 Nov '05

30 Nov '05

I have code that will compile using msvc 7.1 but will not under intel 9.0. Here is some simplified code to illustrate my problem: using namespace boost; using namespace std; typedef array<int, 2> array_type; array_type a; a[0] = 0; a[1] = 1; vector<array_type> v; v.push_back(a); vector<int> h; for_each(v.begin(), v.end(), mem_fun_ref(&array_type::front)); This compiles and runs using msvc 7.1, but intel 9.0 errors with the following: error: more than one instance of overloaded function "mem_fun_ref" matches the argument list: function template "std::mem_fun_ref(_Result (_Ty::*)() const)" function template "std::mem_fun_ref(_Result (_Ty::*)())" argument types are: (<unknown-type>) Here are the two definitions of front for boost::array: reference front() { return elems[0]; } const_reference front() const { return elems[0]; } If I'm reading the error correctly, this means that the intel compiler doesn't know if I want to use the const or non-const version of front. Does anyone know anything about this? Is this the forwarding problem? Is a function wrapper around front a good solution? What are the solutions? Thanks, Chris

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[Boost.Iostream] missing BOOST_IOSTREAMS_DECL in mapped_file.hpp
by Marc Viala 30 Nov '05

30 Nov '05

Hi, I'm not really sure but I think there are some missing export declarations in the "mapped_file.hpp" of Boost.Iostream. The missing declarations are for the struct mapped_file_sink and the class mapped_file. I've joined the corrected "mapped_file.hpp" Could you confirm these observations? Marc Viala

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