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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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[shared_ptr] Detect shared_ptr argument at compile time
by Ralf Globisch 13 Aug '10

13 Aug '10

Hi, I'm not sure if this is the correct mailing list for this question: Is there a way to determine if a template parameters is of type boost::shared_ptr at compile time? I would like to do something like: template<class A> void doSomething( const A& a) { // if "a" is of type boost::shared_ptr<SomeType> a->someMethod(); // else a.someMethod(); } Is this possible at all? Regards, Ralf

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Re: [boost] Problem with program_options on FreeBSD 8 (gcc 4.2)
by elekktretterr＠exemail.com.au 13 Aug '10

13 Aug '10

> Hi Petr, > > My mistake, I, somehow, thought to read that you wanted the static > libraries. Looking at your cmake-code, I would say it appears correct > for finding the static libraries. Did you check whether you really > have those static libraries? Second, are you on windows and could the > auto-linking be in the way? Third, you may need to specify > BOOST_ALL_DYN_LINK as a compile-definition. > Thanks Andre, Im using FBSD 8. -r--r--r-- 1 root wheel 964726 Jul 23 10:22 /usr/local/lib/libboost_program_options.a lrwxr-xr-x 1 root wheel 29 Jul 23 10:23 /usr/local/lib/libboost_program_options.so -> libboost_program_options.so.4 -r--r--r-- 1 root wheel 472959 Jul 23 10:23 /usr/local/lib/libboost_program_options.so.4 I suppose this means that I have both static and dynamic versions of boost. I'll try BOOST_ALL_DYN_LINK next. Petr

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