January 2012 - Boost - lists.preview.boost.org

[filesystem] documentation typo
by Greg Rubino 26 Jan '12

26 Jan '12

Hello, It looks like there's some copy/paste residue in http://www.boost.org/doc/libs/1_48_0/libs/filesystem/v3/doc/reference.html#… basic_filesystem_error has become filesystem_error, but in the anchor it's still called 'basic_filesystem_error', and also there are a couple of references on the page to basic_filesystem_error. This momentarily confused me when I was moving a codebase from v1 to v3 yesterday, so I thought it was worth mentioning. I've entered a trac ticket for this issue: https://svn.boost.org/trac/boost/ticket/6448 but I would be delighted to submit a patch for this since I've been wanting to get more involved in Boost, but it would be my first time doing and I'm not quite sure how to go about it. I assume that it involves checking out the trunk and modifying the necessary files, but I'm not sure after that. Greg

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Boost.Application
by Renato Tegon Forti 26 Jan '12

26 Jan '12

Hi All, I have the first prototype of the "Boost.Application" ready! I would like to receive comments so I can refine the library. Please send your feedback to re.tf(a)acm.org 0) Introduction A Boost.Application allows a developer run your application as a Windows service, as a Unix/Linux daemon, or as a usual interactive application (terminal) without the need to add extra code, the library abstract OS specific API and provide a ease common interface. In case of server application, developer need only compile your code on a Windows to have a ready to play Windows Service or in a UNIX/Linux to have Daemon. CTRL-C signals and SCM (Service Control Manager) controls handlers are available for terminating, pause/resume(windows) the application constructively and many other until methods are available in application class like a single instance running limitation! 1) Download: https://sourceforge.net/projects/boostapp/ 2) Installation: The library is one: Automatic linking You should unpack the files and copy: Boost.Application_pre_alpha_1\boost\application To: boost_1_48_0\boost and, Boost.Application_pre_alpha_1\libs\application To: boost_1_48_0\libs 3) Build Then you must build, for example (in windows): bjam toolset=msvc-9.0 variant=debug threading=multi link=shared define=_BIND_TO_CURRENT_VCLIBS_VERSION 4) Documentation The project has an incomplete documentation: Boost.Application_pre_alpha_1\libs\application\doc\html\index.html 5) Use however, the tutorial explains how to use the lib, and that generally goes like this: ---------------------------------------------------------------------------- -------------------- #include <boost/application/engine.hpp> class myapp : public boost::application::application { protected: int main(const std::vector<std::string>& args) { // your application logic here! while(1) { std::cout << "Hello Boost.Application!" << std::endl; // ... if(state() == boost::application::application_stoped) { break; } } return 0; } }; BOOST_APP(myapp, "MainTutorial1", "Boost.Application Main Tutorial 1!", boost::application::default_application_type, 1, 0, 1) ---------------------------------------------------------------------------- -------------------- The folder: Boost.Application_pre_alpha_1\libs\application\example\tutorial Has all tutorial files! I tested the lib on Windows VC9 (Windows Service) and Ubuntu 11 GCC 4 (Daemon)! 6) Questions: * Is there any interest in this library? * If Yes! What are the refinements? (see todo, for some) Please send your feedback to re.tf(a)acm.org Thanks to all Renato

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Boost.Application (PART II)
by Renato Tegon Forti 26 Jan '12

26 Jan '12

Hi all, I want to emphasize: 1) This is a prototype, a starting point to find out if this is an interesting lib to boost! 2) And if 1 is true! I will compile all comments and make modifications to meet "boost"! My doubt is if this lib don't violate: "The library must be generally useful and not restricted to a narrow problem domain." About comments of friends! First, thank you for the comments! They always show a new way of doing things, which I had not thought of! This is the main reason I'm doing (trying to) this lib, to have the opportunity to learn (and contribute) with you! I will try to enumerate the comments, and then build a path to follow for next version (if [1] is satisfied. Do you think I need more votes to continue the effort?) a) >>So selling it as "ready to play" UNIX/Linux daemon is a bit - erm - exaggerating. Sorry about this, I will change this description! I agree with you! Sorry! b) >> Why is the application not a functor or even a function? . Again I agree with you! This is a better way!, for sample I can handle exception in my main too! Thanks about this suggestion! >> I don't like it, though I don't have an alternative solution at hand. Somehow this feels very clumsy with that init() method. As example of a pure OO approach you could have a look at Qts QApplication. I will look QApplication! If you have time! You could describe what you think would be the right path follows in more detail, I appreciate it! c) >> The biggest concern for me is that you're using narrow strings I will provide wide strings. I don't know how yet. I will check Boost.Filesystem! Besides, there is other example to follow? For sample, I need use W version (GetModuleFileNameW) on all? And use a function like this to convert: inline void convert(const char* from, std::wstring & to, const codecvt_type& cvt) D) Other question, to handle exceptions! Any Idea? e) "Install and uninstall windows service" functionality, be a part of the application instead of a separate one and using a callback. f) * In the unknown mode, the program can run in either mode provided someone puts something in the command line. Could that rather be a callback maybe post initialize such that we tell your application which one we want. This way the developer controls his command line. After all, it might not come from the command line but instead from a configuration file. -------------------------------------------------------------------------- What else? Thanks for help!!!

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boost filesystem path as utf-8?
by Emil Dotchevski 25 Jan '12

25 Jan '12

Hello, I understand that the path class .native() member function's return type differs depending on the platform (wstring on windows, for example.) Is there a way to get the path as a utf-8 string regardless of the platform? Likewise, is there a way to construct a path object from a utf-8 string regardless of the platform? Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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[log][phoenix] Questions on porting to phoenix
by Andrey Semashev 25 Jan '12

25 Jan '12

Hi, [My apologies for the long post] I'm trying to port filters and formatters of Boost.Log to Boost.Phoenix and I'm not sure I understand what's the best way to go. Hope someone can help me out. A short introduction of the terms and what is currently available. * An attribute value is a type-erased value, something similar to boost::any but with more advanced interface to allow visitation and extraction of the stored value. * A log record is an object which contains a set of named attribute values. For simplicity, let's say: class attribute_value; typedef map< string, attribute_value > attribute_values_view; class record { public: attribute_values_view const& attribute_values() const; string const& message() const; }; * A filter is a function that accepts attribute values and returns a bool: typedef function< bool (attribute_values_view const&) > filter; The filter is assumed to pass the log record if it returns true. * A formatter is a function that accepts a log record and a stream and outputs strings or attribute values to the stream: typedef function< void (ostream&, record const&) > formatter; * I already have the code that extracts attribute values from log records. What I'm trying to achieve is something along these lines (this is not a finalized interface yet): enum my_severity { info, warning, error }; BOOST_LOG_REGISTER_ATTRIBUTE("Severity", severity, my_severity) filter flt = severity >= warning; formatter fmt = stream << "[" << severity << "] " << message; Here, "stream" and "message" are keywords provided by Boost.Log, the former is a placeholder for the stream argument of the formatter function, and the latter returns the result of the record::message() method. Now, the BOOST_LOG_REGISTER_ATTRIBUTE macro is what I'm struggling on. It should create a new keyword (severity) which should: 1. Be a POD object to be statically initialized. 2. Contain the information on the type (my_severity) and name ("Severity") of the attribute to be able to extract it from the log record. 3. Be a Phoenix object to initiate lazy expression generation. >From what I gathered from the docs and examples, the generated keyword should be a terminal, in terms of Proto. Am I correct? In order to produce the value, during the evaluation the keyword should receive either a log record or a attribute_values_view and I can't quite understand how do I do that. Basically, I don't quite understand how do I declare and implement a terminal so that it works with Phoenix. This question also applies to the "stream" and "message" keywords but I suspect the solution will be similar. Maybe there is an example of doing this in the docs or elsewhere. I'll be glad if someone provides a link or example of doing this. Thanks in advance.

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[quickboost] single HTML page?
by lcaminiti 24 Jan '12

24 Jan '12

Hello all, Is there a way to have quickbook generate a single HTML page? (Maybe some XSL param...) Right now, different sections appear on different HTML pages. But for a very simple doc, I only have 3 short sections and it'd make more sense for them to be displayed on a single page while still remain separate section and appear separately in the table of context. Thanks a lot. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-quickboost-single-HTML-page-tp4323… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Bug reports - Showstoppers and Regressions
by Marshall Clow 24 Jan '12

24 Jan '12

There are a couple of useful reports on svn.boost.org: Active Showstoppers: https://svn.boost.org/trac/boost/report/43 Active Regressions: https://svn.boost.org/trac/boost/report/30 To shortcut part of the discussion, here are some definitions (taken from https://svn.boost.org/trac/boost/wiki/TicketWorkflow) • Showstopper - this problem is so bad, that we should hold up a release if it's not fixed. Note that the release managers and/or the library maintainers may have different opinions. • Regression - something used to work (in a previous release), but no longer does. IMHO, these bugs should be at least looked at before each release. -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

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[BGL] Any interest in updated maximum adjacency search?
by Fernando Vilas 23 Jan '12

23 Jan '12

Hi, As a part of my graduate research, I have been using the maximum adjacency search algorithm. In the BGL, it is implemented in the stoer_wagner_min_cut functions. I have already broken it out of there, to be a search with a visitor, like BFS. I also implemented a dummy visitor and wrote visitors for my research. It would be very easy to implement a min-cut visitor so that the Stoer-Wagner functionality is maintained without a public API change. As a contributor in other FLOSS projects, I would like to contribute this code back to the Boost library, under the Boost license, if there is interest in the code. That said, this will be my first contribution to Boost, so I would most likely need someone willing to help me navigate the approval process and let me know where the code needs to be improved to meet the normally high standards on this project. -- Thanks, Fernando Vilas fvilas(a)iname.com

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[quickbook] email tag?
by lcaminiti 21 Jan '12

21 Jan '12

Hello all, Is there a preferred way or special tag to specify the author's email within the [library ...] tag? [library Boost.LocalFunction [author [Caminiti, Lorenzo]] ... ] Thanks. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-quickbook-email-tag-tp4310264p4310… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[local] name (was Re: "protected" APIs)
by Lorenzo Caminiti 21 Jan '12

21 Jan '12

On Mon, Jan 16, 2012 at 6:06 AM, Thomas Klimpel <Thomas.Klimpel(a)synopsys.com> wrote: > Hartmut Kaiser wrote: >> > On 01/02/2012 10:25 AM, Lorenzo Caminiti wrote: >> > > Hello all, >> > > >> > > Boost.Closure (formerly, Boost.Local) needs to use some macros, >> types, >> > > etc that are currently marked private in Boost.ScopeExit: >> > >> > Boost.Closure? I really don't like that name is at implies functional >> > programming capabilities. Didn't you decide to name it >> Boost.LocalFunction >> > instead? >> >> I second that concern. I wouldn't like for the local function library >> to >> claim the name 'closure'. >> This would be >> >> a) totally misleading and >> b) inhibits to give that name to a potential real closure library in >> the >> future. > > +1 As I said before, I'm equally happy with Boost.LocalFunction and Boost.Closure. I'm checking with my review manager about going back from Closure to LocalFunction given that a few people have now expressed such a preference. I'll keep everyone posted :) > Or more precisely, just ignoring mails questioning the name Boost.Closure is not good style. In a functional programming language, many things can be done with a closure (for example returning it from a function), and it is unclear to me, whether Boost.Local really is able to approximate this functionality in a sufficiently usable way. It might be true, but then please point me to the corresponding passage in the documentation. Boost.Local docs do not (yet) explain how and when local functions can be returned because that was a homework from the review. I'm pasting below a few examples that I will include in the docs: //[test_return_inc_cpp #include <boost/closure.hpp> #include <boost/function.hpp> #define BOOST_TEST_MODULE ReturnInc #include <boost/test/unit_test.hpp> boost::function<int (void)> inc(int& value) { int BOOST_CLOSURE(bind& value) { return ++value; } BOOST_CLOSURE_END(i) return i; } BOOST_AUTO_TEST_CASE( return_inc ) { int value1 = 0; // Reference valid in scope where closure is used. boost::function<int (void)> inc1 = inc(value1); int value2 = 0; boost::function<int (void)> inc2 = inc(value2); BOOST_CHECK( inc1() == 1 ); BOOST_CHECK( inc1() == 2 ); BOOST_CHECK( inc2() == 1 ); BOOST_CHECK( inc1() == 3 ); } //] //[test_return_setget_cpp #include <boost/closure.hpp> #include <boost/function.hpp> #define BOOST_TEST_MODULE ReturnSetGet #include <boost/test/unit_test.hpp> #include <string> boost::function<void (std::string const&)> set; boost::function<std::string const& (void)> get; void action(void) { // State `message` hidden behind access functions from here. BOOST_CHECK( get() == "abc" ); set("xyz"); BOOST_CHECK( get() == "xyz" ); } BOOST_AUTO_TEST_CASE( return_setget ) { std::string message = "abc"; // Reference valid where closure used. void BOOST_CLOSURE(bind& message, std::string const& text) { message = text; } BOOST_CLOSURE_END(s) set = s; std::string const& BOOST_CLOSURE(const bind& message) { return message; } BOOST_CLOSURE_END(g) get = g; action(); } //] //[test_return_derivative_cpp #include <boost/closure.hpp> #include <boost/function.hpp> #define BOOST_TEST_MODULE ReturnDerivative #include <boost/test/unit_test.hpp> boost::function<int (int)> derivative(boost::function<int (int)>& f, int dx) { int BOOST_CLOSURE(bind& f, const bind dx, int x) { return (f(x + dx) - f(x)) / dx; } BOOST_CLOSURE_END(deriv) return deriv; } BOOST_AUTO_TEST_CASE( return_derivative ) { int BOOST_CLOSURE(int x) { return x + 4; } BOOST_CLOSURE_END(add2) boost::function<int (int)> a2 = add2; // Reference valid where closure used. boost::function<int (int)> d2 = derivative(a2, 2); BOOST_CHECK( d2(6) == 1 ); } //] //[test_return_this_cpp #include <boost/closure.hpp> #include <boost/function.hpp> #define BOOST_TEST_MODULE ReturnThis #include <boost/test/unit_test.hpp> struct number { number(int value) : value_(value) {} boost::function<int (void)> inc(void) { int BOOST_CLOSURE(bind this_) { return ++this_->value_; } BOOST_CLOSURE_END(i) return i; } private: int value_; }; BOOST_AUTO_TEST_CASE( return_this ) { number n1 = 0; // Object valid in scope where closure is used. boost::function<int (void)> inc1 = n1.inc(); number n2 = 0; boost::function<int (void)> inc2 = n2.inc(); BOOST_CHECK( inc1() == 1 ); BOOST_CHECK( inc1() == 2 ); BOOST_CHECK( inc2() == 1 ); BOOST_CHECK( inc1() == 3 ); } //] Thanks. --Lorenzo

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