January 2011 - Boost - lists.boost.org

Build trunk 1.46 libraries problems
by Paul A. Bristow 04 Oct '11

04 Oct '11

I've just updated trunk, and note that version.hpp has been updated to 1.46. When I try to link previous tests, I get messages like LINK : fatal error LNK1104: cannot open file 'libboost_test_exec_monitor-vc100-mt-sgd-1_46.lib' But when I try to rebuild the libraries, they are all still *1.45.* :-( my log file is attached. I also note some config failures that suggest something else may be wrong? ...updating 1 target... compile-c-c++ i:\boost-trunk\boost\bin.v2\libs\math\config\msvc-10.0\debug\threading-multi \has_gcc_visibility.obj has_gcc_visibility.cpp libs\math\config\has_gcc_visibility.cpp(7) : fatal error C1189: #error : "This is a GCC specific test case". call "C:\Program Files\Microsoft Visual Studio 10.0\VC\vcvarsall.bat" x86 >nul cl /Zm800 -nologo @"i:\boost-trunk\boost\bin.v2\libs\math\config\msvc-10.0\debug\threading-mul ti\has_gcc_visibility.obj.rsp" ...failed compile-c-c++ i:\boost-trunk\boost\bin.v2\libs\math\config\msvc-10.0\debug\threading-multi \has_gcc_visibility.obj... ...failed updating 1 target... Performing configuration checks - ../config//has_gcc_visibility builds : no ...found 47 targets... ...updating 1 target... compile-c-c++ i:\boost-trunk\boost\bin.v2\libs\math\config\msvc-10.0\debug\threading-multi \has_long_double_support.obj has_long_double_support.cpp ...updated 1 target... - ../config//has_long_double_support builds : yes ...found 15 targets... ...updating 4 targets... compile-c-c++ i:\boost-trunk\boost\bin.v2\libs\regex\build\msvc-10.0\debug\threading-multi \has_icu_test.obj has_icu_test.cpp libs\regex\build\has_icu_test.cpp(12) : fatal error C1083: Cannot open include file: 'unicode/uversion.h': No such file or directory call "C:\Program Files\Microsoft Visual Studio 10.0\VC\vcvarsall.bat" x86 >nul cl /Zm800 -nologo @"i:\boost-trunk\boost\bin.v2\libs\regex\build\msvc-10.0\debug\threading-mul ti\has_icu_test.obj.rsp" ...failed compile-c-c++ i:\boost-trunk\boost\bin.v2\libs\regex\build\msvc-10.0\debug\threading-multi \has_icu_test.obj... ...skipped <pi:\boost-trunk\boost\bin.v2\libs\regex\build\msvc-10.0\debug\threading-mul ti>has_icu.exe for lack of <pi:\boost-trunk\boost\bin.v2\libs\regex\build\msvc-10.0\debug\threading-mul ti>has_icu_test.obj... ...failed updating 1 target... I've tried changing boost_root and boost-build environment variables to 1.46 but makes no difference. Suggestions. Thanks. Paul --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com

4 7

[serialization] or [spirit] JSON Archives
by Fernando Pelliccioni 08 Sep '11

08 Sep '11

Hi, After experimenting with Spirit.Qi to make a JSON parser, I had the need for a serializer. First, I thought I could serialize my model of JSON (json:: value, json: object, etc.), but that was not compatible with boost::serialization. I am currently writing a ARCHIVE for Boost Serialization, but I'm finding some problems in order to implement JSON correctly. The question is, does anyone know about some files to Boost Serialization already finished? I've seen the Archive made by Esteve Fernandez, but do not serve my purpose, because I just need JSON. I would like to develop a JSON parser which in turn is a compatible Boost Serialization serializer . Any ideas? Thanks and regards, Fernando Pelliccioni.

5 6

[Opaque] Request for interest in Opaque typedefs library emulation
by vicente.botet 27 Jul '11

27 Jul '11

Hi, I have started to play with a class to define opaque typedefs on funcdamental types. It is based on the C++ proposal " Progress toward Opaque Typedefs for C++0X" by Walter E. Brown http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1891.pdf and http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2004/n1706.pdf Please take a look on the preceding links to understand the motivation. Boost.Sericalization provide a BOOST_STRONG_TYPEDEF already, but in my opinon the implementation is not complete,as only the order operators are defined (But maybe I'm wrong). Evidently it can not provide everything we can have with a language approach, but IMO this could yet be useful. The library include two class templates (CRTP) to define opaque types: * public_opaque_type<OT,UT> : implicit conversion from OT to UT * private_opaque_type<OT,UT> : no conversion from OT to UT An opaque type (OT) is a new type, different from the underlying type (UT) and other OT. It defines explicit constructor from the UT, and defines all the operators the UT support but this time applied to the OT. To define a new OT with this mixin classes struct serial_number: public_opaque_type<serial_number, unsigned> { BOOST_OPAQUE_PUPLIC_FORWARD_CONSTRUCTORS(serial_number,unsigned); }; struct game_score: private_opaque_type<game_score, unsigned> { BOOST_OPAQUE_PRIVATE_FORWARD_CONSTRUCTORS(game_score,unsigned); }; In addition, defines macros that make this simpler BOOST_OPAQUE_PUBLIC_TYPEDEF(unsigned, serial_number); BOOST_OPAQUE_PRIVATE_TYPEDEF(unsigned, game_score); Next follows the definition of the public_opaque_type template <typename Final, typename T> class public_opaque_type : boost::totally_ordered< Final , boost::integer_arithmetic< Final , boost::bitwise< Final , boost::unit_steppable< Final , boost::totally_ordered< T, Final // public specific conversions , boost::integer_arithmetic< T, Final // public specific conversions , boost::bitwise< T, Final // public specific conversions > > > > > > > { protected: T val_; typedef public_opaque_type opaque_type; public: typedef T underlying_type; explicit public_opaque_type(const T v) : val_(v) {}; public_opaque_type() {}; public_opaque_type(const opaque_type & rhs) : val_(rhs.val_) {} public_opaque_type & operator=(const opaque_type & rhs) { val_ = rhs.val_; return *this; } public_opaque_type & operator=(const T rhs) { val_ = rhs; return *this; } T const& underlying() const { return val_; } T& underlying() { return val_; } operator const T & () const { return val_; } operator T & () { return val_; } #if 0 bool operator==(const opaque_type & rhs) const { return val_ == rhs.val_; } #endif bool operator<(const Final & rhs) const { return val_ < rhs.val_; } Final& operator+=(const Final & rhs) { val_ += rhs.val_; return static_cast<Final&>(*this); } Final& operator-=(const Final & rhs) { val_ -= rhs.val_; return static_cast<Final&>(*this); } ... }; I have started to make some tests and it works well for the moment. Limitations: * As we can not specialize the behaviour of static_cast/dynamic_cast the library sould provide two specific casts opaque_static_cast and opaque_dynamic_static_cast (Not yet implemented). * As operator.() can not be overloaded, it works transparently only for underlying types that don't defines member functions (C++ fundamental types, as int, char, ...). For the others an explicit use of the underlying() member function is needed :( * Others I have not catched yet :( Do you think it is worth continuing? Please, let me know if you see a error on the design. _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/

4 8

[filesystem] home_directory_path
by Jeff Flinn 24 Jul '11

24 Jul '11

In looking at implementing a portable home_directory_path function a few questions arise. Based on http://en.wikipedia.org/wiki/Home_directory, POSIX and other UNIX flavors 'appear' to be a straight forward use of the "HOME" environment variable. Does anyone have any experience where the "HOME" variable is not the proper source of the user's home directory? Windows NT and above have the "USERPROFILE" environment variable. Using this would be the easiest to use. But I've seen discussion that this may not always be properly defined, in particular if the user has reset their home directory to a non-system drive. I haven't tracked down it's availability on WinCE. Does anyone have experience with this platform? There is the windows GetUserProfileDirectory api function also available since NT4. This is in the Userenv.lib/dll, obviously adding a link dependancy. How are these sorts of system link dependencies handled? Through bjam? Or is it acceptable/better to use #pragma comment(lib,"Userenv.lib")? In looking at some client code using home_directory_path, I see that they generally are looking for the user's Desktop directory(Mac & Windows). Obviously this only makes sense on GUI platforms. The issue with merely getting this path via home_directory_path() / "Desktop" is IIRC, that at least on windows "Desktop" is localized and may not exist with that name on non-english localized systems. Windows has the SHGetFolderPath api. I need to look into Mac's native support. Any thoughts on the general usefulness of a portable desktop_directory_path? Thanks, Jeff

16 60

[mpl] string to type conversion
by Bartosz Marcinkiewicz 19 Jun '11

19 Jun '11

Hello, I would like to have a macro which could be used like this: STRING_TO_TYPE( MyType ) which would yield: typedef mpl::string<'M','y','T','y','p','e'> MyType_id_t; Any ideas how to implement something like that? Thanks for any help, bma. -- Bartosz Marcinkiewicz tel. (+48) 516 034 243 e-mail: bma(a)epcon.pl, bartosz.marcinkiewicz(a)epcon.pl EPCON Sp. z o.o. www.epcon.pl adres: 53-407 Wrocław, ul. Gajowicka 114/116 tel. (+48) 71 361 75 55 ext.36 fax (+48) 71 361 74 44 NIP PL 899-24-92-498 KRS 0000190187 REGON 932963731 Kapitał zakładowy: 500 000 PLN

4 4

Re: [boost] [date_time] Time zone improvements
by Rutger ter Borg 25 May '11

25 May '11

Jeff Garland wrote: > Very cool :-) One question -- is there a portable solution where a user > could deploy a files onto a Windows system or is it a Unix only solution? > I'm fine with incorporating a *nix only solution because what your > suggesting will be a nice solution for *nix platforms, but it will need to > be clear that it's not portable. I don't see why it wouldn't be possible to deploy the (big-endian) binary files to any platform. Getting it into this binary form (using zone info compiler zic) may be harder to do cross-platform, but cygwin may help here. [snip] > As the primary maintainer of Boost date-time I can say with certainty that > there is interest in this functionality -- it's long been on my todo list > and I haven't had time to get to it. You can email me privately and we > can discuss all the details of how to get your code incorporated. I'll do! Regards, Rutger

5 9

[atomic] Status?
by vicente.botet 04 May '11

04 May '11

Hi, There are some libraries that would prefer to be reviewed after Boost.Atomic is reviewed, otherwise them should move the library as an internal detail of the implementation. Could the people working on Boost.Atomic tell us what is the state of the library? Which platforms have been handled? Which part of the standard has been implemented? Could others having knowledge in assembler participate in this project? When we can expect the library to be ready for review? Best, Vicente

10 20

accurate sum accumulator (kahan)
by Gaetano Mendola 27 Apr '11

27 Apr '11

Hi all, I had to implement in terms of boost accumulators the Kahan summation algorithm. I will paste at the end of this message the accumulator, the feature and the extractor source code. This accumulator reduces the numerical error obtained with standard sequential sum, as example the sum of 1e6f elements equal to 1e-6f should give 1.0f, this is the results obtained with sum and sum_kahan: tag::sum: 1.009038925 tag::sum_kahan: 1.000000000 I'm not sure if that sum_kahan is worth to be inserted in the accumulators provided with boost, I'm not an expert of boost:accumulators (I just followed the guide to make this new accumulator) so not sure if you prefer to have a fast_sum and an accurate_sum instead of sum and sum_kahan. Regards Gaetano Mendola // File kahan_sum.hpp #ifndef KAHAN_SUM #define KAHAN_SUM #include <boost/accumulators/framework/accumulator_base.hpp> #include <boost/accumulators/framework/parameters/sample.hpp> #include <boost/numeric/conversion/cast.hpp> namespace boost { namespace accumulators { namespace impl { template<typename Sample> struct sum_kahan_accumulator : accumulator_base { typedef Sample result_type; template<typename Args> sum_kahan_accumulator(Args const & args) : sum(args[sample | Sample()]), compensation(boost::numeric_cast<Sample>(0.0)) { } template<typename Args> void operator ()(Args const & args) { const Sample myTemp1 = args[sample] - this->compensation; const Sample myTemp2 = this->sum + myTemp1; this->compensation = (myTemp2 - this->sum) - myTemp1; this->sum = myTemp2; } result_type result(dont_care) const { return this->sum; } private: Sample sum; Sample compensation; }; }}} namespace boost { namespace accumulators { namespace tag { struct sum_kahan : depends_on< > { typedef impl::sum_kahan_accumulator< mpl::_1 > impl; }; }}} namespace boost { namespace accumulators { namespace extract { extractor< tag::sum_kahan > const sum_kahan = {}; } using extract::sum_kahan; }} #endif

21 68

[MPL] Maintenance, patch applciation etc
by Joel Falcou 10 Mar '11

10 Mar '11

As a huge user of MPL all along, i'm a bit saddened by the speed of patching/evolution of the thingy. Currently there is 36 trac item on MPL and I remember a page with a ncie list of future work to go to. Instead of bitching around, i want to propose me as a "co-maintainer" or w/e the proper term is. I have a small amount of free time i want to dedicate to this. So here is the proposal ;)

6 9

D-style scope guards?
by Martin Christiansson 07 Mar '11

07 Mar '11

Hi, I have used the good old scopeguard in the past and recently done some experiments with the Boost.ScopeExit library. Still I feel that the clean scope statements in D is missing. It will not be possible to do an equally clean solution without having the same features in the language itself, but I could reach as far as this example that reuses the ScopeExit library: void foo() { GUARDED_SCOPE_BEGIN GUARDED_SCOPE_EXIT() { cout << "Returning from foo()" << endl; } GUARDED_SCOPE_EXIT_END GUARDED_SCOPE_SUCCESS() { cout << "foo(): No Errors occurred!" << endl; } GUARDED_SCOPE_SUCCESS_END GUARDED_SCOPE_FAILURE() { cout << "foo(): Exception caught!" << endl; } GUARDED_SCOPE_FAILURE_END GUARDED_SCOPE_END } The GUARDED_SCOPE_BEGIN macro declares one boolean guard to handle return from several levels of nested scopes and one boolean to guard the current scope from exceptions (will be shadowed in nested scopes). GUARDED_SCOPE_END will set the exception_thrown guard to false before that variable is used by the GUARDED_SCOPE_*() destructors. The latter is actually reused ScopeExit code with an added wrapper with a single if-statement. GUARDED_SCOPE_EXIT() will allways run on scope exit. GUARDED_SCOPE_SUCCESS() will only run if the function is exited with wrapper for return keyword (GUARDED_SCOPE_RETURN). The wrapper must be used since it updates the hidden guard variables. Using plain "return" will behave as if exception was thrown. GUARDED_SCOPE_FAILURE() will run when exception is thrown. There is also a separate GUARDED_SCOPE_NESTED_BEGIN that is supposed to be used for all nested scopes. A reference is kept to the return_called variable in the top-level-scope (variable declared by GUARDED_SCOPE_BEGIN). The biggest issue here is that any extra closing curly bracket inserted between GUARDED_SCOPE_*-definitions and GUARDED_SCOPE_END will cause destructors to run before update of guard variable. Could happen if someone thinks it "looks better" without understanding how stuff works. That kind of error will behave as if exception was thrown. Is this something to investigate further? Messy or potentially useful? Suggestions for improvements? I've appended the contents of my small test program at the end of this email. Can be tested by inserting GUARDED_SCOPE_RETURN() and "throw exception();". Regards, /Martin ----------- #include <iostream> #include <exception> #include <boost/scope_exit.hpp> using namespace std; #define GUARDED_SCOPE_BEGIN bool return_called = false; { bool& return_called_ref = return_called; bool exception_thrown = true; #define GUARDED_SCOPE_NESTED_BEGIN { bool& return_called_ref = return_called; bool exception_thrown = true; #define GUARDED_SCOPE_END exception_thrown = false; (void) return_called_ref; } #define GUARDED_SCOPE_RETURN(rc) { return_called_ref = true; return rc; } #define GUARDED_SCOPE_EXIT(Seq) BOOST_SCOPE_EXIT(Seq) #define GUARDED_SCOPE_EXIT_END BOOST_SCOPE_EXIT_END #define GUARDED_SCOPE_SUCCESS(Seq) BOOST_SCOPE_EXIT( (&return_called_ref) (&exception_thrown) Seq) { if(return_called_ref || !exception_thrown) #define GUARDED_SCOPE_SUCCESS_END } BOOST_SCOPE_EXIT_END #define GUARDED_SCOPE_FAILURE(Seq) BOOST_SCOPE_EXIT( (&return_called_ref) (&exception_thrown) Seq) { if(!return_called_ref && exception_thrown) #define GUARDED_SCOPE_FAILURE_END } BOOST_SCOPE_EXIT_END void foo() { GUARDED_SCOPE_BEGIN GUARDED_SCOPE_EXIT() { cout << "Returning from foo()" << endl; } GUARDED_SCOPE_EXIT_END GUARDED_SCOPE_SUCCESS() { cout << "foo(): No Errors occurred!" << endl; } GUARDED_SCOPE_SUCCESS_END GUARDED_SCOPE_FAILURE() { cout << "foo(): Exception caught!" << endl; } GUARDED_SCOPE_FAILURE_END do { GUARDED_SCOPE_NESTED_BEGIN GUARDED_SCOPE_FAILURE() { cout << "Inner scope: Exception caught!" << endl; } GUARDED_SCOPE_FAILURE_END GUARDED_SCOPE_SUCCESS() { cout << "Inner scope: No Errors occurred!" << endl; } GUARDED_SCOPE_SUCCESS_END GUARDED_SCOPE_END } while(0); GUARDED_SCOPE_END } int main() { try { foo(); } catch(exception& e) { cout << "main(): Caught exception: " << e.what() << endl; return -1; } cout << "main(): No Errors occurred!" << endl; return 0; }

9 16