August 2010 - Boost - lists.boost.org

[config] _mingw.h
by Edward Diener 16 Aug '10

16 Aug '10

The config platform file win32.hpp has: # include <_mingw.h> when __MINGW32__ is defined. I do not see _mingw.h anywhere. Where is this header supposed to be ?

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[log] Wide Character Backend file problems
by Sivaram Kannan 15 Aug '10

15 Aug '10

Hi, I was trying to create a log file with wide character support. Similar code with normal character support works well, where as for wide character support the log file itself is not getting created. Here is the code for both types. Can someone tell me, what am I missing with the wide character type. The code compiles, but the log file alone is not getting created when the program is run. //Wide Character version void Log_Init() { boost::function< void (std::wostream&, boost::log::wrecord const&) > formatter = boost::log::formatters::wstream << boost::log::formatters::date_time< boost::posix_time::ptime >(L"TimeStamp") << L" *" << boost::log::formatters::attr< int >(L"Severity") << L"* " << boost::log::formatters::wmessage(); boost::shared_ptr< sinks::synchronous_sink<boost::log::sinks::wtext_file_backend> > sink = boost::log::winit_log_to_file( keywords::file_name = L"C:\\BMR\\Logs\\bmr.log", // file name pattern keywords::rotation_size = 1 * 1024 * 1024, // rotate files every 1 MiB... keywords::open_mode = std::ios_base::app, keywords::auto_flush = true ); sink->locked_backend()->set_formatter(formatter); // Register common attributes boost::log::add_common_attributes(); } //Normal Character version void Log_Init() { boost::function< void (std::ostream&, boost::log::record const&) > formatter = boost::log::formatters::stream << boost::log::formatters::date_time< boost::posix_time::ptime >("TimeStamp") << " *" << boost::log::formatters::attr< int >("Severity") << "* " << boost::log::formatters::message(); boost::shared_ptr< sinks::synchronous_sink<boost::log::sinks::text_file_backend> > sink = boost::log::init_log_to_file( keywords::file_name = "C:\\BMR\\Logs\\bmr.log", // file name pattern keywords::rotation_size = 1 * 1024 * 1024, // rotate files every 1 MiB... keywords::open_mode = std::ios_base::app, keywords::auto_flush = true ); sink->locked_backend()->set_formatter(formatter); // Register common attributes boost::log::add_common_attributes(); }

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Re: [boost] : [chrono] v0.4.5 Documentation update + warnings + removal + bug fixes
by Tan, Tom (Shanghai) 15 Aug '10

15 Aug '10

>Date: Tue, 10 Aug 2010 20:00:15 +0200 >From: "vicente.botet" <vicente.botet(a)wanadoo.fr> >Subject: [boost] [chrono] v0.4.5 Documentation update + warnings removal + bug fixes > >Waiting for the review I plan to add yet a lightweight stopwatch, as suggested by Tom Tan on a personal mail, >which stores a reference to a generalization of the Clock duration or an accumulator of the Clock duration. > I'll concentrate also in improving the documentation and the tests. Hi Vincente, Thanks for the feature. One more request, can you make this following specialization work? //typedef stopclock_accumulator< boost::chrono::process_cpu_clock > process_cpu_stopclock_accumulator; It's commented out in your source code, I assume it does not compile yet. In general, I'd like to see process_cpu_clock to be supported as the first-class citizen like process_real_cpu_clock, process_user_cpu_clock and so on. -Tom

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[bind] [patch] support for result_of
by Stefan Strasser 15 Aug '10

15 Aug '10

Hi, would a full implementation of this patch: https://svn.boost.org/trac/boost/raw-attachment/ticket/4542/bind.patch be accepted to Boost.Bind? it provides support for bind()ing generic function objects and for boost::result_of<F(...)> where F is a result of bind(). for example: struct F{ template<typename T> T operator()(T const &t, int) const{ return t; } template<typename Args> struct result; }; the result type depends on the argument type, so instead of "result_type", "result" is defined according to boost::result_of: template<typename T> struct F::result<F(T const &,int)>{ typedef T type; } this function object can not be used with bind(), because bind() requires F::result_type to be defined. with the patch, you can bind() the function object, and determine the result of the bound function object using result_of: int main(){ g(bind(F(),_1,5)); } template<typename F> void g(F const &f){ double doubleres=f(1.234); //F(1.234,5) -> double boost::result_of<F(int const &)>::type intres=f(1); // F(1,5) -> int } C++ TR1 includes result_of and bind(). it doesn't seem to say anything about result_of<bind()-result> though.

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[DateTime] posix_time_zone incorrect sign?
by Roland Bock 15 Aug '10

15 Aug '10

Hi, I think that posix_time_zone in Boost.DateTime is using the wrong sign for offsets from GMT: According to the documentation, posix_time_zone is modeled after IEEE Std 1003.1. The documentation gives several examples, for instance <cite> "MST-7" This zone is as simple as it gets. This zone lies seven hours west of GMT and has no daylight savings. </cite> But all other sources for IEEE Std 1003.1 I found so far say that negative offsets indicate *east* of GMT, see for instance: http://www.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html <cite> If preceded by a '-' , the timezone shall be east of the Prime Meridian; otherwise, it shall be west (which may be indicated by an optional preceding '+' ). </cite> http://tools.ietf.org/html/draft-ietf-dhc-timezone-01 <cite> The format of the IEEE 1003.1 POSIX timezone specification is defined as follows:[...]If preceded by a '-', the timezone is east of the Prime Meridian, otherwise it is west ('+' is optional) </cite> http://www.twinsun.com/tz/tz-link.htm <cite> Numeric time zone abbreviations typically count hours east of UTC, e.g., +09 for Japan and -10 for Hawaii. However, the POSIX TZ environment variable uses the opposite convention. For example, one might use TZ="JST-9" and TZ="HST10" for Japan and Hawaii, respectively. </cite> IMO, the implementation or the documentation should be changed. Personally, I'd prefer a change in the implementation, even though this would be a rather nasty breaking change. Regards, Roland

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[1.44] Release imminent
by Beman Dawes 14 Aug '10

14 Aug '10

Unless someone objects right away, I plan to start building the release at 1PM, US Eastern Daylight Time. Thanks, --Beman

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[utility] declval addition? [type_traits] add_rvalue_reference addition?
by vicente.botet 14 Aug '10

14 Aug '10

Hi, I was wondering if we can add the declval utility function template to the Boost.Utility library 20.3.4 Function template declval [declval] 1 The library provides the function template declval to simplify the definition of expressions which occur as unevaluated operands (Clause 5). template <class T> typename add_rvalue_reference<T>::type declval() noexcept; // as unevaluated operand 2 Remarks: If this function is used (as defined by (3.2)), the program is ill-formed. 3 Remarks: The template parameter T of declval may be an incomplete type. [ Example: template <class To, class From> decltype(static_cast<To>(declval<From>())) convert(From&&); declares a function template convert which only participats in overloading if the type From can be explicitly converted to type To. For another example see class template common_type (20.7.6.6). -end example ] BTW, add_rvalue_reference is not available on Boost.TypeTraits, add_rvalue_reference_layer. Any problem to add it? Best, _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/

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Need help with boost iostreams
by Martin Sundhaug 14 Aug '10

14 Aug '10

Hello! I am having some difficulties understanding the docs on boost-iostreams, I would appreciate if someone here joined the project to help with among other boost.

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What happened to the subject line here? (was: �)
by Dave Abrahams 14 Aug '10

14 Aug '10

I'm seeing a bunch of threads with garbage subjects. What's going on? -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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[interprocess] Checking for existence Named Mutex
by Brian Davis 13 Aug '10

13 Aug '10

How do I check for the existence of a named resource in using boost interprocess without wrapping a open_only in a try catch block and waiting for the exception?

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