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Bug in lexical_cast<> with doubles
by Leon Raj 29 Jan '05

29 Jan '05

I think I've found a bug in the boost::lexical_cast<> library (v1.31.0) on WinXP SP1, MSVC 6.0 (sp5) and MSVC.NET 2003. --- Start code snippet --- #include <boost/lexical_cast.hpp> #include <iostream> int main( int argc, char* argv[] ) { double dMax = = std::numeric_limits< double >::max(); // On a Win32 x86 system, dMax is now 1.7976931348623157e+308 // This is successful and strMax is "1.797693134862316e+308" std::string strMax = boost::lexical_cast< std::string >( dMax ); try { double newDMax = boost::lexical_cast< double >( strMax ); std::cout << "Successfuly" << std::endl; } catch ( boost::bad_lexical_cast& ) { std::cout << "Failed to cast" << std::endl; } // On a Win32 x86 system, this always fails, // because (I think) strMax overflows a double, // because 1.7976931348623157e+308 is *rounded UP* // to 1.797693134862316e+308, which cannot be // represented by a double } --- End code snippet --- ----------------------------------------------------- Leon Raj Senior Engineer Invetech Pty. Ltd. Phone: +61 3 9211 7000 (Switchboard) +61 3 9211 7938 (DDI) leon.raj(a)invetech.com.au IMPORTANT - This e-mail and any attachments may be confidential. Any retransmissions, dissemination or other use of these materials by persons or entities other than the intended recipient is prohibited. If received in error, please contact us and delete all copies. Before opening or using attachments, check them for viruses and defects. Our liability is limited to resupplying any affected attachments. [Any representations or opinions expressed in this e-mail are those of the individual sender, and not necessarily those of Vision Systems Limited].

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Unit test case inheritance problem
by Bill Lear 29 Jan '05

29 Jan '05

I am having trouble working around a problem with inheriting unit test cases. Suppose I have a base class Foo and several derived classes. Suppose I have a corresponding base test case and I would like to reuse that base test case with test cases for the derived classes. What I would like to do is this, in highly stylized form: class BaseFooTestCase { public: virtual Foo* create() = 0; void test_base() { Foo* foo = create(); // test foo ... } void add(test_suite* ts) { ts->add(BOOST_CLASS_TEST_CASE(&BaseFooTestCase::test_base, this); } }; class DerivedFooTestCase { public: virtual Foo* create() { return new Derived(); } void test_derived() { Foo* foo = create(); // test foo } void add(test_suite* ts) { BaseFooTestCase::add(ts); ts->add(BOOST_CLASS_TEST_CASE(&DerivedFooTestCase::test_derived, this); } }; Then, something like this: test_suite* init_unit_test_suite(int, char* []) { auto_ptr<test_suite> ts(new test_suite("test")); DerivedFooTestCase* tc = new DeriveFooTestCase(); tc->add(ts); return ts; } However, I can't get the add() methods in the test case classes worked out. The BOOST_CLASS_TEST_CASE macro seems to want a shared_ptr, and passing "this" to it does not seem to work. Could anyone please provide an example of how to do this? Every time I try to work this out, I end up with a mess --- static allocator methods, weak_ptr wrapped by shared_ptr, and other workarounds --- all of which works, but is really quite a lot of effort for what I want and is overly complex for me to recommend to my team as a solution. Any help appreciated. Thanks. Bill

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Bug in date_time?
by John Eddy 29 Jan '05

29 Jan '05

If I create a file with nothing but the include: #include <boost/date_time/local_time/local_time.hpp> I get a compiler error (VC7 .NET 2003) having to do with line 149 of tz_db_base.hpp which reads: typedef time_zone_names<charT> time_zone_names; which doesn't seem to make much sense. from a brief inspection of the time_zone_names.hpp file, it seems that line 64 which reads: typedef time_zone_names_base<char> time_zone_names; may shed some light on the solution. Thanks, John

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thread pool help
by Cory Nelson 28 Jan '05

28 Jan '05

I'm coding a simple thread_pool class, with the help of boost. I wrote a simple test case, and things seem to be out of sync - not all the work gets executed. I think I am using boost::condition wrong, can someone take a look? -- Cory Nelson http://www.int64.org

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Re: Re: [Boost-users] Warnings in date_time
by John Eddy 28 Jan '05

28 Jan '05

Jeff, Actually, they turned up at warning level 3. If you would like, I can send you the warnings for level 4. John On Thu, 27 Jan 2005 19:28:53 -0500, John Eddy wrote >> Hello, >> >> I just started using the date-time library and it is a great >> library. > > Thanks. >> There are a few warnings that I have noticed so far that >> could be avoided with some explicit casts. I am using VC .NET 2003. > > Yes, thanks. Turns out it's hard for us to see these because warnings have come out in the regression tests. I notice these still aren't coming out -- I assume this is warning level 4? We'll take care of them, eventually. Some of this code is being redone for 1.33... Jeff

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Re: [string_algo] Split and Predicates
by David Brownell 28 Jan '05

28 Jan '05

Thanks for your quick response, Pavol, this did the trick and cleared up my misunderstanding. Might I suggest an overloaded version of split that takes a string/character string as a delimiter. Althought the implementation details are different, I still think it fits well into the intent of the split algorithm and may clear up issue for others have the same problem as I did. Thanks again for your help! David Brownell "Pavol Droba" <droba(a)topmail.sk> wrote in message news:<20050128071103.GC31065(a)lenin.felcer.sk>... > Hi, > > > It is possible to achieve what you want quite easily. However, split algorithm > is not the right tool for this. > Split is a high level wrapper over the split_iterator and it is quite specialized. > > So this is the code, that should work for you: > > #include <boost/algorithm/string/find_iterator.hpp> > #include <boost/algorithm/string/finder.hpp> > > static char const STRING[] = "this\r\nis\r\n\r\na test!"; > > typedef boost::split_iterator<const char*> char_split_iterator; > > for(char_split_iterator It=char_split_iterator(STRING, boost::first_finder("\r\n"); > It!=char_split_iterator(); > ++It) > { > cout << *It << endl; > } >

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Date-Time gregorian::date construction question
by Wolfgang Fertsak 28 Jan '05

28 Jan '05

If a date object is constructed from an invalid date(e.g. Feb 29th, 2005) and the values are specified in the constructor, an exception is thrown. If the object is constructed from a string representation with from_string(), no exception is thrown and the object has the next valid date (in this case Mar 1st, 2005). Is this a bug or a feature? Best regards, Wolfgang #include <iostream> #include <boost/date_time/gregorian/gregorian.hpp> using namespace boost::gregorian; using namespace std; int main() { try { // throws exception date Date1(2005,2,29); string strDate("2005-02-29"); // throws no exception date Date2 = from_string(strDate); // output is 2005-03-01 cout << to_iso_extended_string(Date2) << endl; } catch(std::exception&e) { cout << e.what() << endl; } return 0; }

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Warnings in date_time
by John Eddy 28 Jan '05

28 Jan '05

Hello, I just started using the date-time library and it is a great library. There are a few warnings that I have noticed so far that could be avoided with some explicit casts. I am using VC .NET 2003. Here are the ones I've noticed so far: in microsec_time_clock.hpp on line 102 which reads: boost::uint32_t sub_sec = (filetime % 10000000) / 10; // microseconds same file, line 118 which reads: int adjust = resolution_traits_type::res_adjust()/1000000; in time_system_counted.hpp on line 57 which reads: typename calendar_type::date_int_type dc = day_count(); in date_parsing.hpp on line 211 which reads: ss << ss.narrow(*beg++, 'X'); // 'X' will cause exception to be thrown Thanks, John

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Error Compiling Boost Graph example/graphviz.cpp
by Welson Sun 28 Jan '05

28 Jan '05

Hi, I would like to parse the graphviz dot file using your read_graphviz in the boost graph library. However, when I compiling the example/graphviz.cpp file, I got the following error: $ g++ graphviz.cpp /cygdrive/c/DOCUME~1/welson/LOCALS~1/Temp/cctY52MA.o(.text+0x602):graphviz.c pp: undefined reference to `boost::read_graphviz(std::basic_string<char, std::char_ raits<char>, std::allocator<char> > const&, boost::subgraph<boost::adjacency_li t<boost::vecS, boost::vecS, boost::directedS, boost::property<boost::vertex_att ibute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocato <char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> , std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, td::allocator<char> > const, std::basic_string<char, std::char_traits<char>, st ::allocator<char> > > > >, boost::no_property>, boost::property<boost::edge_att ibute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocato <char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> , std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, td::allocator<char> > const, std::basic_string<char, std::char_traits<char>, st ::allocator<char> > > > >, boost::property<boost::edge_index_t, int, boost::no_ roperty> >, boost::property<boost::graph_graph_attribute_t, std::map<std::basic string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string< har, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_strin <char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pa r<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, b ost::property<boost::graph_vertex_attribute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::ch r_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std:: har_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic string<char, std::char_traits<char>, std::allocator<char> > const, std::basic_s ring<char, std::char_traits<char>, std::allocator<char> > > > >, boost::propert <boost::graph_edge_attribute_t, std::map<std::basic_string<char, std::char_trai s<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char> std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<cha >, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, s d::char_traits<char>, std::allocator<char> > const, std::basic_string<char, std :char_traits<char>, std::allocator<char> > > > >, boost::property<boost::graph_ ame_t, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, oost::no_property> > > >, boost::listS> >&)' collect2: ld returned 1 exit status However, I can use the write_graphviz to generate the .dot file from a graph, which means I have compiled the library correctly. Do you have any idea what is going on here? Best Regards, Welson Sun ------------------------------------- Electrical and Computer Engineering Brigham Young Unversity 461 CB, Provo, Utah 84602 Office: (801) 422-7206 Email: welson(a)et.byu.edu -------------------------------------

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exception safety of boost graph library
by Ovidiu Deac 28 Jan '05

28 Jan '05

Hello everybody, We are going to use boost graph library within our application and I would like to know if there are any known issues regarding the exception safety. Is the basic guarantee satisfied? Is the strong guarantee satisfied? (see Herb Sutter's definition of basic/strong guarantee in Exceptional C++) "Basic guarantee: Even in the presence of exceptions thrown by T or other exceptions, Stack objects don't leak resources. Note that this also implies that the container will be destructible and usable even if an exception is thrown while performing some container operation. However, if an exception is thrown, the container will be in a consistent, but not necessarily predictable, state. Containers that support the basic guarantee can work safely in some settings. Strong guarantee: If an operation terminates because of an exception, program state will remain unchanged. This always implies commit-or-rollback semantics, including that no references or iterators into the container be invalidated if an operation fails. For example, if a Stack client calls Top and then attempts a Push that fails because of an exception, then the state of the Stack object must be unchanged and the reference returned from the prior call to Top must still be valid." (Herb Sutter, Exceptional C++) Thank you, vidu

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