December 2005 - Boost-users

demo.cpp
by sui tam 01 Dec '05

01 Dec '05

I have successfully compiled the program, However, when I try linking the program, I get the errors: msvcprt.lib(MSVCP60.dll) : error LNK2005: "[Entry] public: bool _cdel std::ios_base::faile(void) const "(.?fail@ios_base@std@@QEBA_NXZ) already defined in library.lib (text_iarchive.obj); and couple of more similiar link errors. How can I fix it? --------------------------------- Yahoo! Personals Single? There's someone we'd like you to meet. Lots of someones, actually. Yahoo! Personals

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demo.cpp
by sui tam 01 Dec '05

01 Dec '05

I have successfully compiled the program, However, when I try linking the program, I get the errors: msvcprt.lib(MSVCP60.dll) : error LNK2005: "[Entry] public: bool _cdel std::ios_base::faile(void) const "(.?fail@ios_base@std@@QEBA_NXZ) already defined in library.lib (text_iarchive.obj); and couple of more similiar link errors. How --------------------------------- Yahoo! Personals Skip the bars and set-ups and start using Yahoo! Personals for free

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I have compilation error as follows:
by sui tam 01 Dec '05

01 Dec '05

compilation error: boost/serialization/access.hpp(123): error: no default constructor exists for class "A" Do I need to change anything in the class at all? Also what are the meanings of these compilation error: boost/serialization/access.hpp(109) error: incomplete type is not allowed. boost/serialization/access.hpp(109) error: expression must have class type __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: [Boost-users] serialize - C structure within a class
by sui tam 01 Dec '05

01 Dec '05

I have a class that is using a C struct, when I use the serialization code: typdef struct A { template <class Archive> void serialize( Archive & ar, ) { ar & a1; ar & a2; } type1 a1; type2 a2; } I get error A.h(59): error: this declaration may not have extern "C" linkage template<class Archive> How can I archive this C structure which the class referenced? --------------------------------- Yahoo! Personals Single? There's someone we'd like you to meet. Lots of someones, actually. Try Yahoo! Personals

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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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[Serialization] Use of BOOST_SERIALIZATION_NVP needs clarification
by Peter Whaite 01 Dec '05

01 Dec '05

I just started using the serialization library and it is very useful. However the minimal documentation for xml archives in the "List of Examples" could be clearer. Right now it says... demo_xml.cpp This is a variation the original demo which supports xml archives in addition to the others. The extra wrapping macros are needed to associate a data item name with the correspoding xml tag. For more information see Name-Value Pairs. Here is what an xml archive looks like. It would help if the "extra wrapping macros" are named. Yes you can figure it out from demo_xml.cpp (well there's only BOOST_SERIALIZATION_NVP in there) and from the "Name-Value Pairs" page, but that is too much jumping around for a first read. But what would help more is a warning that BOOST_SERIALIZATION_NVP must wrap a valid xml tag. For example I naively thought: void editor::save() { ... ar << BOOST_SERIALIZATION_NVP(*this); } would work, but of course it doesnt because "*this" is not a valid xml tag. I searched the list archives, and I'm not the only one who fell into this trap. I suggest adding something like this ... The extra wrapping macro, BOOST_SERIALIZATION_NVP(name), is needed to associate a data item name with the corresponding xml tag. It is importanted that 'name' be a valid xml tag, else it will be impossible to restore the archive. For more information... The warning should be repeated in wrappers.html#nvp, and in the comments in demo_xml.cpp. --- Peter Whaite

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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 30 Nov '05

30 Nov '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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