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Re: [Boost-users] [date_time] posix_time input/output facet symme try
by LABELLE, Maxime 08 Jun '06

08 Jun '06

Jeff Garland wrote something like: > (...) I'm afraid this is a parser bug. I've put together a fix I'd like you to try out. (...) > Download (...) time_facet.hpp and patch it into your boost/date_time/ directory. > > Thanks, > > Jeff Thanks a lot Jeff. It does indeed solve my problem. Thank you for your time. Cheers. Maxime.

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regex_search and match_results issue?
by dave＠superelite.net 08 Jun '06

08 Jun '06

Hi, im having trouble with a base case for regex_search and the number of hits it finds in a haystack. I am wondering if i am not setting flags that need to be set, but i cannot find anything for this in the docs. My usage only seems to find the string "HELLO" once, as the cout indicates xcmMatch.size() is 1 after i run this. I am using boost libs 1.31.00 . Thanks! Heres my code: string sMatchMe = "HELLO"; int theseflags=0; boost::regex xreMatchme(sMatchMe.c_str(), theseflags); boost::cmatch xcmMatch; string stupid = "sdfaHELLOdsfh*sadhfas1d3ahsdf%as&d!adfasdfsdHELLObnbc"; if(regex_search(stupid.c_str(), xcmMatch, xreMatchme)) { cout << "number of matches here should be " << xcmMatch.size() << endl; }

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delaying destructor compile on imcomplete type
by Gottlob Frege 08 Jun '06

08 Jun '06

IIRC, one of boost's smart ptrs can be used with an incomplete type. How is the compile of the destructor delayed? ie ~my_smart_ptr() { get()->~T(); // error: T is an incomplete type } I wondered through lots of the shared_ptr code, but I got a bit bleary-eyed. On that note, does anyone have a script or preprocessor call or something that converts all the boost code into the 'clean and ideal boost'? ie the one without the layers and layers of compiler workarounds, etc? I think that version would be a much easier read. And maybe some day all compilers will support that version too. We can but dream... Tony

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Re: [Boost-users] [spirit] trouble using parse function with rules
by Gabriel Redner 08 Jun '06

08 Jun '06

Sorry, fat-fingered things and the message was sent too early. trying again: Hi all, I am new to spirit, and my only source of information has been the current spirit documentation. I am running into a curious problem in which the manual suggests some code should compile, yet it does not. Test case: ---------------------------------------------------------------------------------------------- #include <boost/spirit/core.hpp> using namespace boost::spirit; int main() { const char *s = "(1)"; rule<> r = ch_p('(') >> int_p >> ch_p(')'); parse(s, r); // compiles OK parse(s, r, space_p); // does NOT compile parse(s, ch_p('(') >> int_p >> ch_p(')'), space_p); // compiles OK } ---------------------------------------------------------------------------------------------- Why does the third parse() compile, but not the second? Does the rule require some kind of adaptor to work in this context? Thanks, -Gabe

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[date_time] posix_time input/output facet symmetry
by LABELLE, Maxime 08 Jun '06

08 Jun '06

I'm experiencing a problem using custom formatting of fractional seconds. const std::string date_string = "2006 Jun 01 999000 23.59.59"; const std::string format_string = "%Y %b %d %f %H.%M.%S"; When using a time_facet together with the "%f" flag, I get a correct output containing a 6-digit number in place of the fractional part. However, using a time_input_facet together with the "%f" flag, I cannot get a correct ptime from an input using the same format as the above example. The problem is twofold : 1) First, the input facet expects a leading '.' otherwise, it parses a special value and fails. [see time_facet.hpp(1035-1049)] This is not the case in an output facet. 2) Second, even if I include a leading dot, the space after the fractional seconds is not consumed, and the parsing of the remainder fails. This means that I need to add an extra space to the input format string. Here is a sample program: --------- #include <cassert> #include <boost/posix_time/posix_time.hpp> Using namespace boost; ... posix_time::ptime time; const std::string input_format = "%Y %b %d %f %H.%M.%S"; // formats are const std::string output_format = "%Y %b %d .%f %H.%M.%S"; // not symmetric const std::string input_date_string = "2006 Jun 01 .999000 23.59.59"; std::string output_date_string; { posix_time::time_input_facet* input_facet = new posix_time::time_input_facet(input_format.c_str()); std::istringstream in(input_date_string); in.imbue(std::locale(std::locale::classic(), input_facet)); in >> time; } { posix_time::time_facet* output_facet = new posix_time::time_facet(output_format.c_str()); std::ostringstream out; out.imbue(std::locale(std::locale::classic(), output_facet)); out << time; output_date_string = out.str(); } assert( output_date_string == input_date_string ); --------- Am I missing something ? Thanks for your help. Maxime LABELLE.

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what happened to smart asserts?
by Graham Mark 07 Jun '06

07 Jun '06

A few years ago Boost included "smart asserts". It no longer does. I've lsearched the boost site and mail archives, but I can't discover why smart asserts are gone. Can anyone tell me? Thanks. G. Mark

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Boost.Signals: strange bug in example program
by Benjamin Winkler 07 Jun '06

07 Jun '06

Hi, I just downloaded the newest boost library 1.33.1 and compiled the "maximum.cpp" example from the Signals library, which goes like this: #include <algorithm> #include <iostream> #include <boost/signals/signal2.hpp> template<typename T> struct maximum { typedef T result_type; template<typename InputIterator> T operator()(InputIterator first, InputIterator last) const { if (first == last) throw std::runtime_error("Cannot compute maximum of zero elements!"); return *std::max_element(first, last); } }; int main() { boost::signal2<int, int, int, maximum<int> > sig_max; sig_max.connect(std::plus<int>()); sig_max.connect(std::multiplies<int>()); sig_max.connect(std::minus<int>()); sig_max.connect(std::divides<int>()); std::cout << sig_max(5, 3) << std::endl; // prints 15 return 0; } As stated, the correct result would be 15 but the output really is 8. However, when I print the values via std::copy(first, last, std::ostream_iterator<T>(std::cout, " ")); I get "8 15 2 1 ", which means that the values are calculated correctly. This error occurs with Microsoft Visual Studio 2005 (8.0) as well as MinGW 3.4.2. I even tried replacing std::max_element() with my own function, which expectedly didn't help. Seems like a bug to me, but I can't track it down. Could it be some issue with copying the iterator? Benjamin Winkler

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Logic Error with boost::lexical_cast
by umut tabak 07 Jun '06

07 Jun '06

Dear all, I am quite new to boost and need some help in problem that I encountered using boost. I am trying to read a .dat file to convert some of the fields to double values. The line format I am trying to read is sth like this GRID* 1086030 7.23756775373e-5.002455787667412 When I use the code it throws a logic_error, I controlled whether I am reading a valid field to convert or not and it is true. So I am using boost::lexical_cast<double>(string..) to convert that into a double value. What might be the problem to throw a logic error.(I know that it is a logic error :-) but I could not figure that out.) I would appreciate some help. Regards

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[boost.multi_array] newbie question: Best use of memory - repost
by Sebastien Fortier 07 Jun '06

07 Jun '06

Since I got no answers I'm reposting I'm currently using multi_array to represent 3D matrices of doubles, I was wondering which would be the best use since the array has to hold a very large amount of data. I' currently testing whith a multi_array of 800x800x100 to hold double or pointers to double and I have memory problems. When I declare the multi_array whith pointers to doubles I can usually go up to 775x775x100 without problems but when I try the same thing with a multi_array of doubles I get a bad alloc error. My real needs for the moment are for a multi_array of 800x600x57 but I will need bigger storage capacity in the near future, what are your sugesstions. Is the multi_array a pointer itself? How is memory management handled? How can go beyond these limits? sebastien.fortier(a)ec.gc.ca

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[future]: combining || and && futures
by Oliver.Kowalke＠qimonda.com 07 Jun '06

07 Jun '06

Hello, could the futures library add support for following construct: ft::simple_future< int > f1 = boost::bind( fac, 4); ft::simple_future< int > f2 = boost::bind( fac, 8); ft::simple_future< int > f3 = boost::bind( fac, 10); ft::future< int > f_or = f1 || f2; ft::future< fu::tuple< int, int > > f_and = f_or && f2; // doesn't compile because no match for 'operator&&' in 'f_or && f2' thx, Oliver

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