July 2010 - Boost - lists.preview.boost.org

bad include guards
by Steven Watanabe 26 Jan '17

26 Jan '17

AMDG The following pairs of files have identical include guards ./boost/concept_check/general.hpp ./boost/concept/detail/msvc.hpp ./boost/concept_check/msvc.hpp ./boost/concept/detail/msvc.hpp ./boost/filesystem/cerrno.hpp ./boost/cerrno.hpp ./boost/interprocess/containers/tree.hpp ./boost/interprocess/containers/detail/tree.hpp ./boost/mpl/min_max.hpp ./boost/mpl/max.hpp ./boost/mpl/vector/aux_/front.hpp ./boost/mpl/list/aux_/front.hpp ./boost/multi_index/identity_fwd.hpp ./boost/multi_index/identity.hpp ./boost/python/pointee.hpp ./boost/python/detail/pointee.hpp ./boost/spirit/phoenix/closures.hpp ./boost/lambda/closures.hpp ./boost/xpressive/proto/v1_/proto_typeof.hpp ./boost/xpressive/proto/proto_typeof.hpp ./libs/config/test/boost_no_dep_nested_class.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_mem_templates.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_std_allocator.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/conversion/test.hpp ./libs/any/test.hpp ./libs/interprocess/example/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/expand_bwd_test_template.hpp ./libs/interprocess/test/allocation_test_template.hpp ./libs/interprocess/test/printcontainer.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/iostreams/test/detail/utf8_codecvt_facet.hpp ./boost/detail/utf8_codecvt_facet.hpp ./libs/regex/test/regress/test_regex_search.hpp ./libs/regex/test/regress/test_partial_match.hpp ./libs/serialization/test/C.hpp ./libs/serialization/test/A.hpp ./libs/xpressive/perf/regex_comparison.hpp ./libs/regex/performance/regex_comparison.hpp ./tools/inspect/time_string.hpp ./tools/common/time_string.hpp In Christ, Steven Watanabe

5 8

Why no non-null smart pointers?
by Ross MacGregor 29 Apr '14

29 Apr '14

I just created a very small smart pointer libary for our project. It will contain two types of shared pointers: SharedHandle and NullableSharedHandle. SharedHandle will be a shared pointer that cannot be null by ensuring a non-null construction while NullableSharedHandle will basically be a typedef for boost::shared_ptr. I firmly believe that code can be made more reliable by minimizing the use of nullable pointers. To this end, I think it is important that we start using non-null pointer types. Ideally the compiler would be able to understand a non-null pointer and catch bugs at compile time, but I think we can still improve things with a few runtime checks. If we make sure that a shared pointer is constructed with a non-null pointer and ban any reset() type methods, we guarentee that it points to something. This can be beneficial for the following reasons: 1. Any function that uses this type will no longer be burdened with precondition checks to make sure variables of this type are not null. 2. It's type is simply more explicit and better explains its function. 3. Moving the non-null check to the creation phase will reduce the possibility of encountering null pointer exceptions at runtime (assuming there are many more pointer references than constructor calls). So my little pointer library seems to make a lot of sense, but if so why hasn't this simple smart pointer variation made it into boost yet? Has this been discussed somewhere already? My search on non-null smart pointers is not revealing much discussion on the topic. Regards, Ross

9 16

[parameter] std proposal
by Lorenzo Caminiti 07 Jan '13

07 Jan '13

Hello all, Is there a C++ standard proposal for named parameter addition? I am looking for an "N-paper" for named parameters similar to N2081 for concepts, or N1962 for contracts. Thank you. -- Sent from my mobile device Lorenzo

6 8

[#pragma once]
by Sid Sacek 18 Nov '12

18 Nov '12

I've worked with the MSVC, Sun and GCC compilers. Each one of them supports #pragma once. Is there any reason to wrap this pragma within #ifdefs? Are there any compilers out there today that don't support this #pragma? #if defined( _MSC_VER ) && ( _MSC_VER >= 1020 ) # pragma once #endif Could we change this coding pattern so that it no longer looks like MSVC is being selfish? -Sid Sacek

17 20

[config] explicit call of operator templates / msvc bug workaround
by Stefan Strasser 10 Oct '12

10 Oct '12

Hi, is there already a macro in Boost.Config that allows you to insert the "template" keyword in the following code for those compilers that require it? struct functor{ template<class T> void operator()(); }; template<class F> void g(F f){ f.template operator()<int>(); //(1) works with GCC and comeau f.operator()<int>(); //(2) works with MSVC } this apparently only applies to operator calls. MSVC accepts both (1) and (2) for regular functions. (instantiating the operator template with an object of type T as argument, like mpl::for_each does, is not an option. I can't construct T.) thanks, Stefan

6 10

[interprocess] message_queue hangs when another process dies
by Sergei Politov 03 Nov '11

03 Nov '11

Hi, I have found the following problem with message_queue on win32 (MSVC 2008 + Windows Vista). Suppose we have 2 processes, one sends messages to queue, another reads them. When reading process dies (for instance using End process) during message_queue.receive the another process hangs in send. As I found during investigation, it tries to lock interprocess mutex, but it is already locked by dead process. So this message queue instance becomes unusable. I attached the example. Steps to reproduce: 1) Start "mq.exe s" (i.e. with argument s) It outs: sender: $PID 2) Start mq.exe without arguments. It outs: receiver: $PID 0 1 2 3 4 This time sender outs: send done: 3) At this point the message queue is empty and receiver waits for messages. End it with Task Manager. 4) Enter some number in sender console and press Enter. 5) The sender hangs in message_queue.send Best Regards, Sergei

6 13

[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

[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

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

[serialization] boost/serialization/path.hpp
by Johan Råde 21 Feb '11

21 Feb '11

There is no boost/serialization/path.hpp. I suggest the following: ---------------------------------------------------------------------------------------------------------------- #ifndef BOOST_SERIALIZATION_PATH_HPP #define BOOST_SERIALIZATION_PATH_HPP // MS compatible compilers support #pragma once #if defined(_MSC_VER) && (_MSC_VER >= 1020) #pragma once #endif #include <boost/config.hpp> #include <boost/filesystem/path.hpp> #include <boost/serialization/level.hpp> BOOST_CLASS_IMPLEMENTATION(boost::filesystem::path, boost::serialization::primitive_type) #ifndef BOOST_NO_STD_WSTRING BOOST_CLASS_IMPLEMENTATION(boost::filesystem::wpath, boost::serialization::primitive_type) #endif namespace boost { namespace serialization { template<class Archive, class String, class Traits> void serialize(Archive& ar, boost::filesystem::basic_path<String, Traits>& p, const unsigned int version) { String s; if(Archive::is_saving::value) s = p.string(); ar & boost::serialization::make_nvp("string", s); if(Archive::is_loading::value) p = s; } }} #endif //-------------------------------------------------------------------------------------------------------------- Comments? Any suggested improvements? --Johan Råde

5 11

[C++0x] Emulation of scoped enums
by Beman Dawes 16 Feb '11

16 Feb '11

The improved type safety of the C++0x scoped enum feature is attractive, so I'd like to start using it as it becomes available in compilers. See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2347.pdf for a description. Note that the committee changed the name from strongly typed enums to scoped enums. See the attached for a boost/detail header that provides macro wrappers that use scoped enums if available, otherwise fall back on C++03 namespaces and unscoped enums. It lets a library write: BOOST_SCOPED_ENUM_START(algae) { green, red, cyan }; BOOST_SCOPED_ENUM_END ... BOOST_SCOPED_ENUM(algae) sample( algae::red ); void func(BOOST_SCOPED_ENUM(algae)); and then a user can write: sample = algae::green; func( algae::cyan ); Comments or suggestions appreciated, --Beman // scoped_enum_emulation.hpp ---------------------------------------------------------// // Copyright Beman Dawes, 2009 // Distributed under the Boost Software License, Version 1.0. // See http://www.boost.org/LICENSE_1_0.txt // Generates C++0x scoped enums if the feature is present, otherwise emulates C++0x // scoped enums with C++03 namespaces and enums. The Boost.Config BOOST_NO_SCOPED_ENUMS // macro is used to detect feature support. // // Caution: only the syntax is emulated; the semantics are not emulated and // the syntax emulation doesn't include being able to specify the underlying type. // // See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2347.pdf for a // description of the feature. Note that the committee changed the name from // strongly typed enums to scoped enums. // // Sample usage: // // BOOST_SCOPED_ENUM_START(algae) { green, red, cyan }; BOOST_SCOPED_ENUM_END // ... // BOOST_SCOPED_ENUM(algae) sample( algae::red ); // void foo( BOOST_SCOPED_ENUM(algae) color ); // ... // sample = algae::green; // foo( algae::cyan ); #ifndef BOOST_SCOPED_ENUM_EMULATION_HPP #define BOOST_SCOPED_ENUM_EMULATION_HPP #include <boost/config.hpp> #ifndef BOOST_NO_SCOPED_ENUMS # define BOOST_SCOPED_ENUM_START(name) enum class name # define BOOST_SCOPED_ENUM_END # define BOOST_SCOPED_ENUM(name) name #else # define BOOST_SCOPED_ENUM_START(name) namespace name { enum enum_t # define BOOST_SCOPED_ENUM_END } # define BOOST_SCOPED_ENUM(name) name::enum_t #endif #endif // BOOST_SCOPED_ENUM_EMULATION_HPP

14 27

[process] How to run test cases
by Boris 23 Jan '11

23 Jan '11

As Boost.Process 0.3 has been released it would be great if the test cases are run on various platforms. So far I've tested Boost.Process on WinXP with MSVC 9.0, Cygwin with g++ 3.4.4 and Solaris with g++ 3.4.6 and Sun C++ 5.9. To make it as easy as possible for others to run the test cases here's a short description of how to proceed. Nearly all test cases depend on a program called "helpers". This program is built first and is started by many test cases as a child process. In order to find the program "helpers" the test cases must know its location. As there is no way to get the location at runtime it is hardcoded in the file libs/process/test/misc.hpp. As the location differs depending on what compiler is used YOU MUST CHECK FIRST THE PATH IN libs/process/test/misc.hpp! Otherwise most of the test cases will fail as they look for a program "helpers" in the wrong directory. As of today only those paths are correct and have been tested which are set for Windows, Cygwin and Solaris. Only after you have checked and maybe updated the path in libs/process/test/misc.hpp you should try to build and run the test cases: WinXP/MSVC 9.0 ************** With MSVC 9.0 you only need to open the Visual Studio 2008 Command Prompt, change to the directory with the test cases and run bjam: C:\boost_1_36_0\libs\process\test> ..\..\..\bjam.exe -q Cygwin/GCC 3.4.4 **************** On Cygwin it's important to know if the Boost libraries have been built for the POSIX or Windows API. By default Boost libraries on Cygwin use the Windows API. With the Windows API the Boost.Process test cases are not passed successfully though (there are compiler errors where I'm not sure currently if they are a Boost.Process problem and how they could be fixed). If you want to run the test cases on Cygwin you must (re-)build the Boost libraries to use the POSIX API: $ cd ~/boost_1_36_0 $ ./bjam cxxflags=-DBOOST_POSIX_API Afterwards you can run the test cases: $ cd ~/boost_1_36_0/libs/process/test $ ../../../bjam cxxflags=-DBOOST_POSIX_API -q Solaris/GCC 3.4.6 ***************** At first you have to put the following line in ~/user-config.jam: using gcc : : : <linker-type>sun ; Then start building the Boost libraries: $ cd ~/boost_1_36_0 $ ./bjam --toolset=gcc cxxflags=-mcpu=ultrasparc For the test cases to be passed successfully you must update Boost.Test. Change line 624 in ~/boost_1_36_0/boost/test/impl/execution_monitor.ipp temporarily to: - , m_CHLD_action( SIGCHLD, catch_system_errors, attach_dbg, alt_stack ) + , m_CHLD_action( SIGCHLD, false, attach_dbg, alt_stack ) It is important that the second parameter is false as the signal SIGCHLD should not be handled by the execution monitor and should not be reported as an error. Afterwards the test cases can be run: $ cd ~/boost_1_36_0/libs/process/test $ ../../../bjam --toolset=gcc cxxflags=-mcpu=ultrasparc -q Solaris/Sun C++ 5.9 ******************* Build the Boost libraries with the sun toolset: $ cd ~/boost_1_36_0 $ ./bjam --toolset=sun stdlib=sun-stlport For the test cases to be passed successfully you must update Boost.Test. Change line 624 in ~/boost_1_36_0/boost/test/impl/execution_monitor.ipp temporarily to: - , m_CHLD_action( SIGCHLD, catch_system_errors, attach_dbg, alt_stack ) + , m_CHLD_action( SIGCHLD, false, attach_dbg, alt_stack ) It is important that the second parameter is false as the signal SIGCHLD should not be handled by the execution monitor and should not be reported as an error. If you run the test cases now you'll get this compiler error for one test case: "../../../boost/asio/detail/socket_ops.hpp", line 218: Error: Cannot assign void* to char*. "../../../boost/asio/detail/socket_ops.hpp", line 229: Error: Cannot assign void* to char*. "../../../boost/asio/detail/descriptor_ops.hpp", line 66: Error: Cannot assign void* to char*. "../../../boost/asio/detail/descriptor_ops.hpp", line 72: Error: Cannot assign void* to char*. The bug has been reported to the Boost.Asio mailing list. If you want to build that one test case, too, you need to fix the two files in Boost.Asio 1.36.0 yourself. All the test cases can be built and run with: $ cd ~/boost_1_36_0/libs/process/test $ ../../../bjam --toolset=sun stdlib=sun-stlport -q

4 9

[SoC] BGL project idea
by Gautam Sewani 03 Jan '11

03 Jan '11

Hi, I am a Computer Science student hoping to contribute to Boost for this year's summer of code. I had a few questions regarding the BGL project idea (https://svn.boost.org/trac/boost/wiki/SoC2010#Boost.Graph) for SOC 2010. 1. I can think of only a few places where the suggested algorithms will be used. Does the community think that these algorithms are used frequently enough to put them in a library? How important does the community consider this project? 2. Will the project proposal be expected to include the API design? Thanks and Regards Gautam

5 29

[GIL] [patch] read multipage TIFF files
by Robert Pollak 29 Nov '10

29 Nov '10

Hello, the following patch (against the current trunk) allows to read any page of a multipage TIFF file, by optionally specifying the zero-based directory number. (The correct term for a TIFF page is "directory".) It adds a "dirnum" to the relevant functions, and uses the corresponding libtiff functionality. The "dirnum" default value is 0 for compatibility with present callers. Additionally, it defines the function tiff_get_directory_count to get the number of directories in the TIFF file. Please give me some feedback or consider applying the patch. This patch would close the corresponding feature request https://svn.boost.org/trac/boost/ticket/2373 . Credits go to Roland Richter, whose code the patch is based on. Best Regards, Robert Pollak Index: boost/gil/extension/io/tiff_io.hpp =================================================================== --- boost/gil/extension/io/tiff_io.hpp (revision 64065) +++ boost/gil/extension/io/tiff_io.hpp (working copy) @@ -122,9 +122,13 @@ protected: TIFF *_tp; public: - tiff_reader(const char* filename) { + tiff_reader(const char* filename,tdir_t dirnum=0) { io_error_if((_tp=TIFFOpen(filename,"r"))==NULL, "tiff_reader: fail to open file"); + if(dirnum>0) { + io_error_if(TIFFSetDirectory(_tp,dirnum)!=1, + "tiff_reader: fail to set directory"); + } } ~tiff_reader() { TIFFClose(_tp); } template <typename View> @@ -171,10 +175,10 @@ private: CC _cc; public: - tiff_reader_color_convert(const char* filename) : - tiff_reader(filename) {} - tiff_reader_color_convert(const char* filename,CC cc_in) : - tiff_reader(filename),_cc(cc_in) {} + tiff_reader_color_convert(const char* filename,tdir_t dirnum=0) : + tiff_reader(filename,dirnum) {} + tiff_reader_color_convert(const char* filename,CC cc_in,tdir_t dirnum=0) : + tiff_reader(filename,dirnum),_cc(cc_in) {} template <typename View> void apply(const View& view) { point2<std::ptrdiff_t> dims=get_dimensions(); @@ -336,18 +340,34 @@ }; /// \ingroup TIFF_IO +/// \brief Returns the number of directories in the TIFF file +inline int tiff_get_directory_count(const char* filename) { + TIFF *tif; + io_error_if((tif=TIFFOpen(filename,"r"))==NULL, + "tiff_get_count: fail to open file"); + + int dircount = 0; + do { + dircount++; + } while (TIFFReadDirectory(tif)); + + TIFFClose(tif); + return dircount; +} + +/// \ingroup TIFF_IO /// \brief Returns the width and height of the TIFF file at the specified location. /// Throws std::ios_base::failure if the location does not correspond to a valid TIFF file -inline point2<std::ptrdiff_t> tiff_read_dimensions(const char* filename) { - detail::tiff_reader m(filename); +inline point2<std::ptrdiff_t> tiff_read_dimensions(const char* filename,tdir_t dirnum=0) { + detail::tiff_reader m(filename,dirnum); return m.get_dimensions(); } /// \ingroup TIFF_IO /// \brief Returns the width and height of the TIFF file at the specified location. /// Throws std::ios_base::failure if the location does not correspond to a valid TIFF file -inline point2<std::ptrdiff_t> tiff_read_dimensions(const std::string& filename) { - return tiff_read_dimensions(filename.c_str()); +inline point2<std::ptrdiff_t> tiff_read_dimensions(const std::string& filename,tdir_t dirnum=0) { + return tiff_read_dimensions(filename.c_str(),dirnum); } /// \ingroup TIFF_IO @@ -356,17 +376,17 @@ /// Throws std::ios_base::failure if the file is not a valid TIFF file, or if its color space or channel depth are not /// compatible with the ones specified by View, or if its dimensions don't match the ones of the view. template <typename View> -inline void tiff_read_view(const char* filename,const View& view) { +inline void tiff_read_view(const char* filename,const View& view,tdir_t dirnum=0) { BOOST_STATIC_ASSERT(tiff_read_support<View>::is_supported); - detail::tiff_reader m(filename); + detail::tiff_reader m(filename,dirnum); m.apply(view); } /// \ingroup TIFF_IO /// \brief Loads the image specified by the given tiff image file name into the given view. template <typename View> -inline void tiff_read_view(const std::string& filename,const View& view) { - tiff_read_view(filename.c_str(),view); +inline void tiff_read_view(const std::string& filename,const View& view,tdir_t dirnum=0) { + tiff_read_view(filename.c_str(),view,dirnum); } /// \ingroup TIFF_IO @@ -375,25 +395,25 @@ /// Throws std::ios_base::failure if the file is not a valid TIFF file, or if its color space or channel depth are not /// compatible with the ones specified by Image template <typename Image> -void tiff_read_image(const char* filename,Image& im) { +void tiff_read_image(const char* filename,Image& im,tdir_t dirnum=0) { BOOST_STATIC_ASSERT(tiff_read_support<typename Image::view_t>::is_supported); - detail::tiff_reader m(filename); + detail::tiff_reader m(filename,dirnum); m.read_image(im); } /// \ingroup TIFF_IO /// \brief Allocates a new image whose dimensions are determined by the given tiff image file, and loads the pixels into it. template <typename Image> -inline void tiff_read_image(const std::string& filename,Image& im) { - tiff_read_image(filename.c_str(),im); +inline void tiff_read_image(const std::string& filename,Image& im,tdir_t dirnum=0) { + tiff_read_image(filename.c_str(),im,dirnum); } /// \ingroup TIFF_IO /// \brief Loads and color-converts the image specified by the given tiff image file name into the given view. /// Throws std::ios_base::failure if the file is not a valid TIFF file, or if its dimensions don't match the ones of the view. template <typename View,typename CC> -inline void tiff_read_and_convert_view(const char* filename,const View& view,CC cc) { - detail::tiff_reader_color_convert<CC> m(filename,cc); +inline void tiff_read_and_convert_view(const char* filename,const View& view,CC cc,tdir_t dirnum=0) { + detail::tiff_reader_color_convert<CC> m(filename,cc,dirnum); m.apply(view); } @@ -401,31 +421,31 @@ /// \brief Loads and color-converts the image specified by the given tiff image file name into the given view. /// Throws std::ios_base::failure if the file is not a valid TIFF file, or if its dimensions don't match the ones of the view. template <typename View> -inline void tiff_read_and_convert_view(const char* filename,const View& view) { - detail::tiff_reader_color_convert<default_color_converter> m(filename,default_color_converter()); +inline void tiff_read_and_convert_view(const char* filename,const View& view,tdir_t dirnum=0) { + detail::tiff_reader_color_convert<default_color_converter> m(filename,default_color_converter(),dirnum); m.apply(view); } /// \ingroup TIFF_IO /// \brief Loads and color-converts the image specified by the given tiff image file name into the given view. template <typename View,typename CC> -inline void tiff_read_and_convert_view(const std::string& filename,const View& view,CC cc) { - tiff_read_and_convert_view(filename.c_str(),view,cc); +inline void tiff_read_and_convert_view(const std::string& filename,const View& view,CC cc,tdir_t dirnum=0) { + tiff_read_and_convert_view(filename.c_str(),view,cc,dirnum); } /// \ingroup TIFF_IO /// \brief Loads and color-converts the image specified by the given tiff image file name into the given view. template <typename View> -inline void tiff_read_and_convert_view(const std::string& filename,const View& view) { - tiff_read_and_convert_view(filename.c_str(),view); +inline void tiff_read_and_convert_view(const std::string& filename,const View& view,tdir_t dirnum=0) { + tiff_read_and_convert_view(filename.c_str(),view,dirnum); } /// \ingroup TIFF_IO /// \brief Allocates a new image whose dimensions are determined by the given tiff image file, loads and color-converts the pixels into it. /// Throws std::ios_base::failure if the file is not a valid TIFF file template <typename Image,typename CC> -void tiff_read_and_convert_image(const char* filename,Image& im,CC cc) { - detail::tiff_reader_color_convert<CC> m(filename,cc); +void tiff_read_and_convert_image(const char* filename,Image& im,CC cc,tdir_t dirnum=0) { + detail::tiff_reader_color_convert<CC> m(filename,cc,dirnum); m.read_image(im); } @@ -433,23 +453,23 @@ /// \brief Allocates a new image whose dimensions are determined by the given tiff image file, loads and color-converts the pixels into it. /// Throws std::ios_base::failure if the file is not a valid TIFF file template <typename Image> -void tiff_read_and_convert_image(const char* filename,Image& im) { - detail::tiff_reader_color_convert<default_color_converter> m(filename,default_color_converter()); +void tiff_read_and_convert_image(const char* filename,Image& im,tdir_t dirnum=0) { + detail::tiff_reader_color_convert<default_color_converter> m(filename,default_color_converter(),dirnum); m.read_image(im); } /// \ingroup TIFF_IO /// \brief Allocates a new image whose dimensions are determined by the given tiff image file, loads and color-converts the pixels into it. template <typename Image,typename CC> -inline void tiff_read_and_convert_image(const std::string& filename,Image& im,CC cc) { - tiff_read_and_convert_image(filename.c_str(),im,cc); +inline void tiff_read_and_convert_image(const std::string& filename,Image& im,CC cc,tdir_t dirnum=0) { + tiff_read_and_convert_image(filename.c_str(),im,cc,dirnum); } /// \ingroup TIFF_IO /// \brief Allocates a new image whose dimensions are determined by the given tiff image file, loads and color-converts the pixels into it. template <typename Image> -inline void tiff_read_and_convert_image(const std::string& filename,Image& im) { - tiff_read_and_convert_image(filename.c_str(),im); +inline void tiff_read_and_convert_image(const std::string& filename,Image& im,tdir_t dirnum=0) { + tiff_read_and_convert_image(filename.c_str(),im,dirnum); } /// \ingroup TIFF_IO

2 7

[fusion] [intro] ADAPT_STRUCT extensions
by Stefan Strasser 04 Oct '10

04 Oct '10

Hi, in the discussion about the library I called "Intro" at the time it has been suggested to use BOOST_FUSION_ADAPT_STRUCT of Boost.Fusion for data member access. based on that I'd like to propose two extensions to ADAPT_STRUCT, which I think are useful beyond my use case: 1) ADAPT_STRUCT can adapt public data members only. with the modifications I uploaded here: http://svn.boost.org/svn/boost/sandbox/intro/boost/fusion/adapted/struct/ all data members can be adapted. for example: class A{ private: friend class fusion::access; int a; }; BOOST_FUSION_ADAPT_STRUCT(A,(int,a) ) 2) adaption of a class including its base class members. for example: struct A{ int a; }; struct B{ int b; }; struct C : A,B{ int c; } BOOST_FUSION_ADAPT_STRUCT(A,(int,a) ) BOOST_FUSION_ADAPT_STRUCT(B,(int,b) ) BOOST_FUSION_ADAPT_DERIVED( C, (A)(B), (int,c) ) an instance of C is now a fusion sequence of size 3. http://svn.boost.org/svn/boost/sandbox/intro/boost/fusion/adapted/struct/ad… private inheritance is supported as above, virtual inheritance is not. I'm not sure if virtual inheritance can be supported.

8 30

[Boost-users] [BGL] Stoer–Wagner min-cut algorithm
by Daniel Trebbien 26 Sep '10

26 Sep '10

> The usual idiom for that in BGL algorithms is to use an > iterator_property_map on the graph's vertices, built using a vector and > indexed by the vertex_index property map of the graph. You can also use a > shared_array_property_map, which manages its storage internally. If you > are doing a generic algorithm, the logic to manage these maps correctly is > somewhat difficult. One place to look for a template of what to do is the > distance map handling at the bottom of > <boost/graph/dijkstra_shortest_paths.hpp>, particularly > dijkstra_shortest_paths() and detail::dijkstra_dispatch1(). The basic > logic is to look at the named parameter structure that the user passes is > and see if there is an assignment map there. If so, use it; otherwise, > look for a vertex_index map in the named parameter structure, defaulting > to get(vertex_index, g), then use the found vertex_index map to create an > iterator_property_map or shared_array_property_map. Now that compilers > are more compliant, there are probably simpler ways to implement the logic > than to use multiple dispatch functions, but the approach in > dijkstra_shortest_paths.hpp is known to work. > > When you get this algorithm done, you may want to contribute it to BGL to > be added to Boost. We are always interested in new algorithms. > > -- Jeremiah Willcock Hello Jeremiah, I would very much like to contribute my implementation of the Stoer–Wagner min-cut algorithm to BGL. In preparation for this, I have attached a "pre-release" version to this e-mail which has everything needed to build the test case with g++ and GNU Make. Before I add in all of the template code to support "default" template parameters and other niceties, I figured that it would be good to have a review of the code to make sure that I am headed in the right direction. Also, I have tested my code against the example from Stoer & Wagner (1997). It appears to be working correctly, but there might be bugs. I think that it would be good to have more testing. Would someone please review my code? Also, is anyone aware of good examples for testing min-cut implementations? Daniel

4 57

[Review] Formal Review: Boost.Move
by OvermindDL1 19 Sep '10

19 Sep '10

Greetings Boost Developers and Users, It's my pleasure to announce that the review of Ion Gaztañagas' Move library starts May 10th and lasts until May 24th, 2010, unless an extension occurs. What is it? =========== The Boost.Move library would supply an emulated C++1x Move semantics interface, aka RValue References, allowing for a wide variety of easy to use and easy to add in optimization abilities. The most used function it would add would be: val_b = boost::move( val_a ); Which would move val_a to val_b; val_a should not be used after this line. This semantic allows for a vast amount of optimizations, especially in regards to temporaries, see the documentation for further examples and use. Other patterns emulated are && rvalue references for functions/members and constructors. There are also a number of STL containers in the sandbox that support move semantics using this library for higher efficiency. Getting the library =================== The latest version of this library may be downloaded from SVN: http://svn.boost.org/svn/boost/sandbox/move/ and the docs may be viewed here Docs: http://igaztanaga.drivehq.com/libs/move/doc/html/index.html and do note, this library is header-only and is designed to be absolutely generic to be useful in all areas of C++ programming. Writing a review ================ If you feel this is an interesting library, then please submit your review to the developer list (preferably), or to the review manager. Here are some questions you might want to answer in your review: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick - reading? In-depth study? - Are you knowledgeable about the problem domain? And finally, every review should answer this question: - Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. Special considerations ====================== If you want or need a primer on the subject, please look at the working draft for C++1x. This linked site has also been shown to be quite useful in describing move usefulness: Want Speed? Pass by Value.: http://cpp-next.com/archive/2009/08/want-speed-pass-by-value/ Move It With Rvalue References: http://cpp-next.com/archive/2009/09/move-it-with-rvalue-references/ And there are further links in that series, but those two will get you started in the domain. Best regards, OvermindDL1, Review Manager (Boost.Move)

15 78

Any interest in dynamic dispatching mechanism from "interface" to template functions ?
by Raffi Enficiaud 16 Sep '10

16 Sep '10

Hello all, The idea behind is not new and consists in dispatching a call of an interface function to the correct template instance, depending on the runtime or compile time parameters. The field of application is (to me) the release of static/dynamic libraries including functions with a predefined set of types combination. This way, the library (compiled once) can easily be plugged to another framework or a script program (I personally use it with boost.python). An example of use could be (general idea, not a real code of course): // -------------- template <class real_type> int template_function(real_type const& r_class1, double param_d, int& param_out) { // ... return 0; } int interface_function(MyInterface const* i_class1, variant const& param, variant& out) { // return value int return_value; // constructs the dispatcher object with a reference to the values passed to interface_function dispatcher<int, MyInterface const*, variant const&, variant&> dispatch_object(return_value, i_class1, param, out); bool res = dispatch_object.calls_first( fusion::vector_tie( template_function < class_t1 >, template_function < class_t2 > //... ) ); if(res) return return_value; return -1; } // -------------- The dispatch_object tests for the convertibility of each instance ui of the arguments Ui of the interface function, with the corresponding argument Ti of the template function. The type of matching is defined by external objects, with a simple interface providing two methods: a convertibility test and a conversion. The types are "cleaned" in order to have a limited number of conversion structures. Currently this mechanism is used in a generic image processing library. The images have all the same virtual interface and the dispatch calls the correct template function based on the concrete type of the image. It also includes a "back conversion" for Ui's that are non-const reference or pointers. The dispatch mainly makes use of boost.fusion, boost.mpl and boost.function_types. I have checked a little bit the Boost.Vault but, correct me if I am wrong, the current dispatching mechanisms do not address exactly this issue. The code is already open-source released under the boost license. I can put some samples in the Vault if there is any interest. Your comments are very welcome ! Kind regards, Raffi Enficiaud

4 11

boost.lockfree update
by Tim Blechmann 31 Aug '10

31 Aug '10

hi all, i've did some updates to boost.lockfree the biggest difference to earlier snapshots is, that it includes a fixed-size single-producer/single-consumer ringbuffer. besides, the documentation is based on doxygen now. snapshots are available from [1], docs from [2] and my git repository can be found at [3] and cloned from [4]... cheers, tim [1] http://tim.klingt.org/code/projects/boost-lockfree/files [2] http://tim.klingt.org/boost_lockfree/ [3] http://tim.klingt.org/git?p=boost_lockfree.git [4] git://tim.klingt.org/boost_lockfree.git -- tim(a)klingt.org http://tim.klingt.org The first question I ask myself when something doesn't seem to be beautiful is why do I think it's not beautiful. And very shortly you discover that there is no reason. John Cage.

11 29

[Boost][website] SSL certificate
by admin＠thefireflyproject.us 18 Aug '10

18 Aug '10

I recently switched from Firefox to Chromium, and I've been having issues accessing [1]https://svn.boost.org. It seems that the SSL certificate used for [2]svn.boost.org is either not properly configured, or not issued by one of the major SSL certificate providers (e.g. VeriSign, GoDaddy). Examination of the certificate indicates that it's issued by the Computer Science Department of Indiana University, and the certificate doesn't have a chain that leads back to a well known CA (the chain is just '[3]svn.boost.org => [4]cs.indiana.edu', and most browsers I've tried don't recognize [5]cs.indiana.edu as a legitimate CA by default). If this isn't just a matter of improper configuration (or, for that matter, just a matter of my browsers being screwy), I'd be happy to offer my own SSL certificate to Boost. The certificate is a standard SSL certificate issued by GoDaddy (domain controlled validation, certificate signing algorithm is RSA 2048 bits), and it's paid through 02/20/2011. I'm currently using my cert for my Debian mirror, so I would have to revoke the current certificate, and then submit a CSR from [6]boost.org's server. Ideally, then I would generate a CSR request, and the boost server would sign it; I'd end up with a cert chain of 'mysite => [7]boost.org => GoDaddy'. [8]boost.org and subdomains would have a cert signed directly by GoDaddy, so the [9]svn.boost.org cert would be verify by most browsers automatically. If there's any interest in this, please let me know. - Bryce Lelbach References 1. https://svn.boost.org/ 2. http://svn.boost.org/ 3. http://svn.boost.org/ 4. http://cs.indiana.edu/ 5. http://cs.indiana.edu/ 6. http://boost.org/ 7. http://boost.org/ 8. http://boost.org/ 9. http://svn.boost.org/

9 12

outer class `this` in local classes
by Lorenzo Caminiti 16 Aug '10

16 Aug '10

Hello all, Is there a way to access the outer class `this` from a local class but without using inheritance? Let me explain with an example: class x { // outer class public: void g() {} void f() { this->g(); // (1) struct y: x { // local class *** using inheritance *** y(x* super): x(*super) {} // (2) void h() { this->g(); // (3) } }; y(this).h(); } }; *** Is there a way to do this but without inheriting `y` from `x`? *** At line (3), the local class `y` can access the outer class `x::g()` simply using `this` because `y` inherits from `x`. However, this inheritance requires to construct another object `x` when `y` is constructed as in line (2) adding runtime overhead and requiring `x` to have an accessible copy constructor. In my application, I need line (3) to essentially look like line (1) so you can program code inside `y` members as if it were inside `x` members. A part from that, the local class `y` could look as it is needed to solve this problem -- with some member variables, other member functions, etc. (For example, I tried to redefine `y::operator->()`/`y::operator*()` to return a pointer/reference to `x` but this does not work because `this->`/`*this` always retain its pointer semantics and they do not use the user defined operators...) Thank you very much. -- Lorenzo

2 3

[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

4 3

[1.44] Beta progress?
by Beman Dawes 10 Aug '10

10 Aug '10

It will be Wednesday before I can start pulling the 1.44 beta together. In the meantime, does anyone have any serious issues we need to tackle before the beta? Thanks, --Beman

15 125

Any interest in creating new CORBA IDL to C++ mapping?
by Johnny Willemsen 10 Aug '10

10 Aug '10

Hi all, We are talking with various users of TAO to see if we can create a new modern IDL to C++ mapping. The idea is to drop all old compilers which lead to the current mapping and make a new IDL to C++ mapping that is using the latest draft C++0x standard. We want to use full STL, shared_ptr, r-value, and everything else we could need. The idea is to prototype this first in TAO and than see if on the long term we can propose a new IDL to C++ V2 mapping to the OMG I did find some discussions on this list about 2 years ago, are people interested in this effort, any input is welcome. Johnny Willemsen Remedy IT www.theaceorb.nl

12 22

[1.44] Release notes
by Daniel James 09 Aug '10

09 Aug '10

Hello, If you haven't done so yet, with the beta coming out it's a good time to add your entries to the release notes so that people know what to test. You can edit the file in subversion here: http://svn.boost.org/svn/boost/website/public_html/beta/feed/history/ Or if you prefer, you can email me the details and I'll add it for you. If you're able to build the release notes, I better warn you that I've changed the build system a little. Recent versions of quickbook are generating slightly different mark up, and if that's used for old entries, they can appear as new in rss feeds. So to avoid that, it now stores a hash of the quickbook files to only update their entry if the source changes. It should just work, you just need to commit the '*-hashes.txt' files at the same time as the rss files. If you want to force an update, you can delete the appropriate line in the text file. thanks, Daniel

5 7

[mpl] BOOST_MPL_HAS_XXX_TEMPLATE_NAMED_DEF
by Edward Diener 09 Aug '10

09 Aug '10

I found the BOOST_MPL_HAS_XXX_TEMPLATE_NAMED_DEF macro in the latest has_xxx.hpp of mpl on the trunk. Is BOOST_MPL_HAS_XXX_TEMPLATE_NAMED_DEF ( and its corresponding BOOST_MPL_HAS_XXX_TEMPLATE_DEF ) scheduled to be added to Boost in an upcoming release ? I find it useful for TMP introspection in much the same way as BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF ( and its corresponding BOOST_MPL_HAS_XXX_TRAIT_DEF ).

5 10

[intrusive] recursive intrusive data structures
by Tim Blechmann 09 Aug '10

09 Aug '10

hi all, is there an easy way to define recursive data structures? something like: struct my_node: boost::intrusive::list_base_hook<> { boost::intrusive::list<my_node> children; }; i am currently using a base class as helper, which causes very dirty code, since i explicitly need to cast from the base to the main class all over the place: struct my_node_base: boost::intrusive::list_base_hook<> {}; struct node: my_node_base { boost::intrusive::list<my_node_base> children; }; thanks, tim -- tim(a)klingt.org http://tim.klingt.org Life is really simple, but we insist on making it complicated. Confucius

2 4

[bcp] Bcp namespace rename causes compile errors on multiple libraries (type_traits, range, spirit, foreach, regex, iostreams) in 1.43
by Cliff Green 04 Aug '10

04 Aug '10

Has bcp namespace renaming been tested against all Boost libraries in 1.43? I'm getting compile errors in (or caused by) the following libraries: type_traits, range, spirit, foreach, regex, iostreams (more details later in this message). The compile errors are from a full bjam build of Boost. I haven't compiled tests or built against my work project code, so I suspect there's more errors in header-only libraries. I'm using g++ 4.1.2 on Linux (although these errors are not compiler specific - I'll also be compiling with VC++ 8.0 at some point). All of these errors are easily fixed, and are "boost" text substitution problems. I was able to get all libraries to build after my changes, but I would rather not use hacked-up source (I prefer to work with the Boost developers and install non-modified Boost source into our Clearcase COTS VOB). However, with these (obvious) compile errors, I'm wondering if the bcp namespace facilities are being tested with all Boost libraries? If not, can I work with John Maddock or someone to set up a test process? Besides doing a full extract / rename and build of the libraries, as many examples and tests as possible should also be compiled to find errors in header-only libraries not brought in to the library source build. Of course it's possible all of the errors I've found have been introduced with new code in 1.43 (which still brings up the need to do a full bcp test before a Boost release), or that I somehow incorrectly used bcp, or there's fixes that haven't been applied to the mainline in SVN. My use case is a perfect fit for the bcp namespace facilities - my work team delivers an SDK (which links to and uses various Boost libraries) to another group which also links to and uses Boost libraries in their own application (everything builds into the same executable). Currently our work team is constrained to using the same Boost version, but we'd like to break this constraint (in particular, for other groups to use our SDK). We use (or will use) enough Boost libraries that bcp on the ones we care about pulls in about 80% of Boost, so I went ahead and ran bcp on all of Boost. Details of the compile failures: -- In type_traits: integral_promotion.hpp, promote.hpp, floating_point_promotion.hpp, header guard probs - original code #ifndef FILE_boost_type_traits_integral_promotion_hpp_INCLUDED #define FILE_boost_type_traits_integral_promotion_hpp_INCLUDED After running bcp with "MyProj_Boost" for the namespace, the header guard is: #ifndef FILE_boost_type_traits_integral_promotion_hpp_INCLUDED #define FILE_MyProj_Boost_type_traits_integral_promotion_hpp_INCLUDED -- In range/config.hpp there's two macros where bcp namespace substitution is incorrectly being applied to the "boost" prefix in boost_range_array: #define BOOST_RANGE_ARRAY_REF() (boost_range_array) #define BOOST_RANGE_ARRAY_REF() (&boost_range_array) Similarly, in range/detail/implementation_help.hpp, the following lines have incorrect substitution: boost_range_silence_warning( boost_range_array ); -- In Phoenix and Wave, there's a bit of namespace substitution problems, where "namespace phoenix" (in multiple files, such as spirit/home/classic/phoenix) is being replaced with "MyProjectphoenix", and in wave/grammars/cpp_intlit_grammer.hpp and cpp_chlit_grammar.hpp there's "namespace phx=phoenix". -- In regex/v4/regex_traits.hpp: BOOST_MPL_HAS_XXX_TRAIT_DEF(boost_extensions_tag) The "boost" prefix in boost_extensions_tag is improperly substituted. -- In foreach.hpp, "boost_foreach_argument_dependent_lookup_hack_value" is not substituted in the enum, but in macros where the enum is used, the substitution is occurring. In iostreams/close.hpp, close_boost_stream on line 143 is being improperly substituted. --- As already mentioned, there's easy changes for each of these. But, is a better answer to make the bcp search and substitution smarter? (I have no idea how easy or hard that would be.) Cliff

3 5

[GIL] color_convert
by fabien.castan＠free.fr 04 Aug '10

04 Aug '10

Hi, I use the GIL extension: HSL. I need to make conversions from hsl to other colorspaces. So I define generic default conversion using intermediate rgb colorspace. I define 2 templates: * default_color_convert<C1,hsl_t> * default_color_convert<hsl_t,C2> But it creates an ambiguity with rgba_t, because it defines the same thing for rgba_t: * default_color_convert<C1,rgba_t> * default_color_convert<rgba_t,C2> So default_color_convert<hsl_t,rgba_t> is ambiguous. The only solution I see is: * to remove default_color_convert<C1,rgba_t> * to define gray_t->rgba_t, rgb_t->rgba_t * to remove default_color_convert<C1,hsl_t> * to define default_color_convert<cmyk_t,C2> So all colorspaces have to: * define a generic conversion to another colorspace using an intermediate rgb colorspace conversion * redefine the conversion for colorspaces we want to make a direct conversion Best regards, Fabien Castan /// \ingroup ColorConvert /// \brief Converting CMYK to any pixel type. Note: Supports homogeneous pixels only. /// /// Done by an intermediate RGB conversion template <typename C2> struct default_color_converter_impl<cmyk_t,C2> { template <typename P1, typename P2> void operator()(const P1& src, P2& dst) const { typedef cmyk_t C1; typedef typename channel_type<P1>::type T1; typedef typename channel_type<P2>::type T2; pixel<T2,rgb_layout_t> tmp; default_color_converter_impl<C1,rgb_t>()(src, tmp); default_color_converter_impl<rgb_t,C2>()(tmp, dst); } }; /* /// \ingroup ColorConvert /// \brief Converting any pixel type to RGBA. Note: Supports homogeneous pixels only. template <typename C1> struct default_color_converter_impl<C1,rgba_t> { template <typename P1, typename P2> void operator()(const P1& src, P2& dst) const { typedef typename channel_type<P2>::type T2; pixel<T2,rgb_layout_t> tmp; default_color_converter_impl<C1,rgb_t>()(src,tmp); get_color(dst,red_t()) = get_color(tmp,red_t()); get_color(dst,green_t())= get_color(tmp,green_t()); get_color(dst,blue_t()) = get_color(tmp,blue_t()); get_color(dst,alpha_t())= channel_convert<T2>(alpha_or_max(src)); } }; */ /// \ingroup ColorConvert /// \brief Converting grayscale pixel type to RGBA. Note: Supports homogeneous pixels only. template <> struct default_color_converter_impl<gray_t,rgba_t> { template <typename P1, typename P2> void operator()(const P1& src, P2& dst) const { typedef gray_t C1; typedef typename channel_type<P2>::type T2; get_color(dst,red_t()) = get_color(src,gray_color_t()); get_color(dst,green_t())= get_color(src,gray_color_t()); get_color(dst,blue_t()) = get_color(src,gray_color_t()); get_color(dst,alpha_t())= channel_convert<T2>(alpha_or_max(src)); } }; /// \ingroup ColorConvert /// \brief Converting grayscale pixel type to RGBA. Note: Supports homogeneous pixels only. template <> struct default_color_converter_impl<rgb_t,rgba_t> { template <typename P1, typename P2> void operator()(const P1& src, P2& dst) const { typedef rgb_t C1; typedef typename channel_type<P2>::type T2; get_color(dst,red_t()) = get_color(src,red_t()); get_color(dst,green_t())= get_color(src,green_t()); get_color(dst,blue_t()) = get_color(src,blue_t()); get_color(dst,alpha_t())= channel_convert<T2>(alpha_or_max(src)); } }; /// \ingroup ColorConvert /// \brief Converting RGBA to any pixel type. Note: Supports homogeneous pixels only. /// /// Done by multiplying the alpha to get to RGB, then converting the RGB to the target pixel type /// Note: This may be slower if the compiler doesn't optimize out constructing/destructing a temporary RGB pixel. /// Consider rewriting if performance is an issue template <typename C2> struct default_color_converter_impl<rgba_t,C2> { template <typename P1, typename P2> void operator()(const P1& src, P2& dst) const { typedef typename channel_type<P1>::type T1; default_color_converter_impl<rgb_t,C2>()( pixel<T1,rgb_layout_t>(channel_multiply(get_color(src,red_t()), get_color(src,alpha_t())), channel_multiply(get_color(src,green_t()),get_color(src,alpha_t())), channel_multiply(get_color(src,blue_t()), get_color(src,alpha_t()))) ,dst); } }; /// \ingroup ColorConvert /// \brief Converting HSL to any pixel type. Note: Supports homogeneous pixels only. /// /// Done by an intermediate RGB conversion template <typename C2> struct default_color_converter_impl<hsl_t,C2> { template <typename P1, typename P2> void operator()(const P1& src, P2& dst) const { typedef hsl_t C1; typedef typename channel_type<P1>::type T1; typedef typename channel_type<P2>::type T2; pixel<T2,rgb_layout_t> tmp; default_color_converter_impl<C1,rgb_t>()(src, tmp); default_color_converter_impl<rgb_t,C2>()(tmp, dst); } }; /// \ingroup ColorConvert /// \brief Unfortunately HSL to HSL must be explicitly provided - otherwise we get ambiguous specialization error. template <> struct default_color_converter_impl<hsl_t,hsl_t> { template <typename P1, typename P2> void operator()(const P1& src, P2& dst) const { static_for_each(src,dst,default_channel_converter()); } };

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Re: [boost] [GIL] kth_channel_view
by fabien.castan＠free.fr 03 Aug '10

03 Aug '10

>A good example of using kth_channel_view is this: > > rgb8_image_t img( 100, 100 ); > typedef typename kth_channel_view_type< 0, const rgb8_view_t>::type view_t; > view_t first = kth_channel_view<0>( const_view( img )); Another interesting possibility is: typedef kth_channel_view_type< 0, const rgb8_view_t> KthChannelView; typename KthChannelView::type first = KthChannelView::make( const_view(img) ); It can be a good thing to directly use channel type, like this: typedef channel_view_type< red_t, const rgb8_view_t>::type view_t; view_t first = channel_view<red_t>( const_view( img )); I have written some code to do that, based on kth_channel_view_type. It's maybe intersting to include in gil. Regards, Fabien namespace boost { namespace gil { template <typename Channel, typename View> struct channel_type_to_index { static const int value = gil::detail::type_to_index< typename color_space_type<View>::type, // color (mpl::vector) Channel // channel type >::type::value; //< index of the channel in the color (mpl::vector) }; template <typename Channel, typename View> struct channel_view_type : public kth_channel_view_type<channel_type_to_index<Channel,View>::value, View> { static const int index = channel_type_to_index<Channel,View>::value; typedef kth_channel_view_type<index, View> parent_t; typedef typename parent_t::type type; static type make(const View& src) { return parent_t::make(src); } }; /// \ingroup ImageViewTransformationsKthChannel template <typename Channel, typename View> typename channel_view_type<Channel,View>::type channel_view(const View& src) { return channel_view_type<Channel,View>::make(src); } }}

2 1

Any interest in trap_exceptions functionality?
by Andy Venikov 02 Aug '10

02 Aug '10

Hi, I often find myself wanting a generic way to catch and process exceptions. For example, imaging having to export "C" interface from a C++ library. You would create a bunch of extern "C" functions that would invoke the right C++ code. One of the things that needs to be done in every such function is to catch and process all exceptions. Most of the exceptions-handling code would look the same or very similar (the same list of exceptions to catch, same way to handle given exception types). C++ to C is not the only place where you'd need this. Most of the module boundaries might want to trap exceptions. The first thing that developers do in these cases is they start generalizing the handling part. I.e., you'd create a separate function/functor that would handle an exception of a certain kind. Unfortunately it still leaves you with a barage of try/catch() statements in every function that doesn't want to leak exceptions. This creates not only the unpleasant look of a lot of catches (one might argue this point), but it creates a lot of repetition - you need to create catch statement for every exception you want to handle. It would be nice if I could assemble all the exceptions I want to handle (honoring their order) and the way to handle them in one single place under a single object. And then invoke that object on all functions that need to be called. I recently took a crack at this task and came up with a generic way to trap exception. Here's a brief API: trap_exceptions(<list-of-exception-handlers>); The previous line would create a callable object. The parameters are a variable number of exceptions handlers that could be either function pointers, references to functions or functors. One thing they have in common though is the signature: the signature should be "void(T)", where T is the type of the exception that the handler will handle. This "T" type is what the trap_exceptions-created callable object will use in the "catch" statements. Other important notes: the order of handlers is important as this will be the order of "catch" statements (i.e., trap_exceptions(HandleBase, HandleDerived) will hide all Derived exceptions). Whether the exception is caught by reference or by value is also controlled by the handler's signature. Signature "void()" means catch all exceptions indiscriminately. Specifying an empty parameter list will also mean to catch all exceptions indiscriminately. The result of the trap_exceptions call can be assigned to a variable: auto ex_trap = trap_exceptions(HandleEx1, HandleEx2, HandleEx3); //BOOST_AUTO can be used too. And I think it will be possible to use //it without registering HandleEx1 etc.) This object can now be used on multiple functions of any arity and any return type. Functors are supported too. ex_trap(func1); //will create a delayed-call object that upon invocation will call func1 and catch exceptions Ex1, Ex2 and Ex3 So, if func1 has signature int(int, char*, float), then ex_trap(func1)(1, "abc", .5); will call function func1 with the given set of arguments and catch afore-mentioned exceptions. The return type undergoes a significant transformation though. Since the return from this delayed function call now returns more information than before (the additional part being whether an exception has been thrown or not), this additional information is conveyed through the use of boost::optional. In the case of ex_trap+func1, the result will be boost::optional<int>. Functions/functors returning void have a special treatment though since unfortunately it's illegal to instantiate boost::optional<void>. For functions that return void, the return type of the delayed call will be a simple bool. There are some return types that have a special value that indicates "error" and could be used to indicate that an exception occured. In this case, just for convenience purposes, it'll be possible to specify this value and the return type will become the return type of the inner function, not optional<T>. I.e: //Let's say that -1 can be used to indicate that an exception has //occured, then ex_trap(func1, -1)(1, "abc", .5);//will have a return type of int. //-1 will be returned if an exception has been thrown and now all places that had return func1(1, "abc", .5); could simply be replaced with return ex_trap(func1, -1)(1, "abc", .5); //without using boost::optional I think one other use of this functionality can be in functional-style programming in C++. While it's trivial to convert syntactic constructs like "if", "while", "switch", and "for" to functional representations (i.e. if_(f1(), f2(), f3()); which means if (f1()) f2(); else f3(); ), it's a lot harder to create a functional representation of try/catch construct. trap_exceptions is an attempt at that. To illustrate that point more, say we have a tuple (or a fusion-like container) which contains a collection of functions/functors. Using fusion::transform it's possible to add certain qualities to these functions. With trap_exceptions, it'll be possible to add a "no exception leak" quality to this set of functions. Do you think a functionality like that will be useful for boost? Any comments are appreciated. Thanks, Andy. P.S. Currently I implemented this functionality in terms of C++0x. But I think it should be possible to use Boost to make it C++03 compatible.

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Proposal for New Multiple-Precision/ Arbitrary-Precision Numbers Library
by Reetesh Mukul 02 Aug '10

02 Aug '10

Hi, I know the purposes and necessities of a Multiple-Precision and Arbitrary Precision Numbers Library in C++ have echoed many a times in BOOST mail chain. Moreover in past and in present many such efforts have been on to address these needs( Google SoC, XINT, and many others ). I too have a long, consistent interest in this area and so is this proposal. I am putting some of the points in Q & A format. Q. What does Numbers mean here ? A. As a long standing definition, Numbers would mean a “Set”. However for most of the practical reasons, and in particular in relation to Natural Numbers/Integers, it would mean a set with Peano’s Arithmetic or Principle Ideal Domain or Finite Field ( ‘or’ here is in inclusive sense). In most of the cases these Sets will be generated out of Rings. As an example, Natural Numbers can be created by mapping Set of “unsigned int”s (which can be treated as Finite Field) to an Indexed Family of “unsigned int”. One such mapping is “radix” (a0 + a1*r + a2*r^2 + a3*r^3+ ...) based arithmetic. Clearly the library has long term intention to provide support for such mappings which has flavors of being generic. Q. What does Multiple-Precision and Arbitrary precision means here ? A. If the cardinality of indexing set (mentioned above) is finite and known at compile time then it will be the case of multiple-precision else it will be arbitrary precision. Both Arbitrary and Fixed precision have a meaning that they are multiple of a unit precision. We will use the term multiple-precision as an alias to fixed precision, however I see chances of debate over this topic. In its implementation paradigms, the current library has notions of multiple-fixed-precision and multiple-unfixed-precision. In current writing I am denoting multiple-fixed-precision as fixed/multiple precision while multiple-unfixed-precision as arbitrary-precision. That multiple-precision maps to cardinality of indexing set additionally asserts that unit of computation will be Elements of Rings of a given kind and bits/bytes will be of particular interest only. To give additional meaning to finiteness of multiple-precision arithmetic, like specifying it in terms of bits, bytes or range of values that the generated number would have, will mean creating compositions of mapping described in last question. Q.What are some basic APIs that the library will expose? A. This is yet to be finalized. However some design paradigms are settled. I already described the core Mathematics in last two questions. There will be a conception of “varch”(Virtual Architecture). This would mean providing a set of functions like mov, add, addto, or, xor, ... which underlying processor provides. Thus one can do - addto(unsigned int* dest, unsigned int* src, unsigned int n), which adds “src” to “dest” (like operator+=) assuming “unsigned int” is a “finite field” and the “pointers” and “n” means n-sized indexed family of “unsigned int”. Definitely there will be “addto”s corresponding to each of the Ring and Mappings. The “arithmetic concepts” corresponding to each “addto” will be deduced based on types involved, and in case “arithmetic concepts” thus deduced are ill-formed or wrong or void, compile time errors will be generated. These varch functions will be provide very low level interface(with respect to intended library) and internally they will be fine-tuned for underlying processor, system, compiler and algorithms. Numbers will be represented as an object via a kernel called basic_mint (which in turn will use varch’s function):- template<typename SignedType=varch::U, typename IntegerType=unsigned int, std::size_t InitialSize=0, precision::value_type P=default_precision<InitialSize>::value, typename IntegerTraits=integer_traits<IntegerType>, typename Allocator=allocator<IntegerType> > struct basic_mint; Further there will be conception of “generators” which will handle Algebra of underlying types. Q. How much is done ? A. Not much. However some of the above ideas have been implemented. One can see pieces of codes here:- http://sourceforge.net/p/spring-math/svn/. A very large portion of code is to be implemented. I thought, before I go too far, too far where design and implementation buckles, I should get “concept-check” by BOOST Gurus. Q. Will it be wrapped around GMP ? A. No, No and No. C++ has richer Algebraic content. Q. Is there any final API where user can use it the way int/char/float are used is specified. A. Not yet. But at most it will be a thin compile time wrapper around basic_mint. Q. Why I came here? A. For guidelines, help, ideas, warnings, disciplines, lectures, volunteers and inherent desire to register initials of my work :). With Regards, Reetesh Mukul

3 4

[MPL] More lazy evaluation, for ease of use?
by jcarey＠jcarey.best.vwh.net 02 Aug '10

02 Aug '10

According to Boost MPL documentation, "Every Integral Constant is also a nullary Metafunction, returning itself." Put another way: redundant evaluation of an Integral Constant is harmless. This handy guarantee encourages Metafunctions to evaluate their integral arguments upon demand. As others have pointed out before, such lazy evaluation reduces "typename ...::type" syntactic clutter, makes it easier to avoid instantiating a template with parameters it does not support, and tends to increase compilation speed. However, other Boost MPL concepts do not impose this self-return requirement, and many Boost MPL standard data types do not provide such a guarantee. In particular, I think it would be helpful if all Sequences, Iterators, and Lambda Expressions were also nullary Metafunctions returning themselves. (In particular, it would be nice if generic containers designed for lazy data could accommodate Lambda Expressions.) Furthermore, it would be helpful if more standard Metafunctions evaluated their arguments. In particular, if boost::mpl::eval_if were to evaluate its condition argument, then nested ifs would be much easier to write, because nested conditions would not have to be legal for all template parameters. Perhaps the reason for not evaluating certain arguments is backward compatibility? Personally, I think the convenience of widespread lazy evaluation would outweigh the costs of a transition to new Metafunctions and concepts. In particular, uniform lazy evaluation would reduce the burden on beginners to figure out which arguments must be evaluated, and which must *not* be evaluated. Instead, beginners could learn the simple rule to leave arguments unevaluated unless there is some good, documented reason to do otherwise. One special note: It is useful for MPL Metafunctions to be able to reason about arbitrary C++ types, even if those types do not happen to be nullary Metafunctions. For example, a canonical use of MPL is to compute the type returned by a function template. To that end, we could wrap arbitrary types just as we wrap integral values in Integral Constant types, and then unwrap them only at need. For example, we could define: template< typename X > struct box { typedef box type; typedef X content; }; template< typename B > struct open : B::type::content {}; and then compute with "box" instances instead of raw types, and apply "open" only when a raw type is actually required. What do you all think?

4 4

[ptr_container] ptr_vector transfer from C array of pointers documentation
by Number Cruncher 02 Aug '10

02 Aug '10

The documentation for ptr_vector::transfer( iterator before, T** from, size_type size, bool delete_from = true ) implies that the operation "delete [] from" is executed, but having examined the source, I don't think it is. This is actually the behaviour I need. I'm trying to convert a std::vector<T*> to a boost::ptr_vector<T*>, i.e. I have a vector of pointers which is solely responsible for "owning" the objects being pointed to, and I want to create a ptr_vector which will automatically clean up the objects when it goes out of scope. I need to do the transfer so that no memory leaks in the event of an exception. As far as I can see, this is exactly what ptr_vector::scoped_deleter is doing: it will delete any of the copied pointers, but it never actually deletes the "from" pointer; presumably because you don't know whether operator new[] was used when allocating it. Can anyone clear up/confirm that this will work: std::vector<T*> v1; v1.push_back(new T); boost::ptr_vector<T> v2; if (!v1.empty()) { v2.transfer(v2.end(), &v1[0], v1.size(), true); } // from this point, don't care about v1 and v2 will handle deletion of T objs Thanks, Simon

2 2

[date_time] Constructing ptime object from ISO 8601 compliant strings
by Rush Manbert 31 Jul '10

31 Jul '10

A variation on this question was asked by Allen Cronce back in May, but I didn't see any answer posted. The Posix Time description begins: "Defines a non-adjusted time system..." I assume that this means it is not adjusted for time zone? I need to construct ptimes from ISO 8601 compliant strings that may contain time zone information, such as this: "2010-08-17 12:34:56-07:00" If I constructed a ptime using this string, then used to_iso_string() to convert it to a string, I would expect to see "2010-08-17T19:34:56", but I don't. Rather, what I see is "2010-08-17T12:34:56" because the time zone portion of the string was ignored. Does anyone have a suggestion for dealing with this situation? I have some ideas, but would be interested to hear what others have done. Thanks, Rush

1 0

Please, remove me from Trac and maintainers.txt
by Gennaro Prota 30 Jul '10

30 Jul '10

Hi, I received a notification for the following Trac ticket. <https://svn.boost.org/trac/boost/ticket/4495> Apparently this request <http://lists.boost.org/Archives/boost/2010/06/168338.php> got just ignored, so I'll try to be clearer: I don't want to have anything to do with Boost; can anyone put an end to this annoyance? Thanks. -- Gennaro __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

4 5

Patches for OpenVMS support for Boost (Asio mostly)
by Artyom 30 Jul '10

30 Jul '10

Hello, I want to submit patches for Boost, mostly Asio for better support of OpenVMS IA64 for 32 and 64 bit builds. The fixes come from an organization I work for that prefers to stay anonymous for security reasons. We've mostly concerned about Boost.Asio and we've managed to compile and run all Boost.Asio unit tests actually giving VMS very good Asio support. The fixes cover several independent libraries that should be fixed in order to make them compile: - Boost.Asio - mostly, configuration and 64 bit quirks - Boost.Test - 64 bit issues and compiler issues. - Boost.Config - added new vms.hpp platform config. - Boost.DateTime - 64 bit fixes. - Boost.Thread - compiler issues workarounds. - Boost.Function - 64 bit fixes as sizeof(size_t) < sizeof(void *); I understand that many library maintainers should be involved in integration of these patch. And it is **very important** for the organization I work for to submit them to upstream Boost in order to make an upgrade to future Boost versions simpler. Questions: - How should I submit so wide patch that covers many libraries? Artyom. P.S.: The patch is attached.

4 10

[context] new version
by Oliver Kowalke 30 Jul '10

30 Jul '10

I've uploaded a new version which takes care of the FLS on Windows. Oliver

2 4

[interprocess] Superfluous "volatile" in atomic_add_unless32
by Capehart, Nolan 29 Jul '10

29 Jul '10

In this: inline bool atomic_add_unless32(volatile boost::uint32_t *mem, boost::uint32_t value, volatile boost::uint32_t unless_this) I think "volatile" on the last argument has no purpose and probably reduces speed slightly. Will it not merely cause the compiler to fetch the formal argument from memory every time it's needed? And isn't that of no use since nothing is modifying the formal argument during the function execution? So: 1) Caller puts actual argument on stack. 2) Caller calls atomic_add_unless32. 3) atomic_add_unless32 treats stack variable as volatile, wasting time (not much) because variable isn't actually changing.

1 0

[gsoc] boost.heap update
by Tim Blechmann 29 Jul '10

29 Jul '10

hi all, i've uploaded a new snapshot of boost.heap. it includes some of the proposed changes and i have also added a benchmark sections. during the final time for the gsoc, i'd like to get the library ready for a review ... therefore, i uploaded a new snapshot [1] and an updated documentation [2]. feedback welcome ... cheers, tim [1] http://tim.klingt.org/code/attachments/download/31/boost_heap_280710.tar.gz [2] http://tim.klingt.org/boost_heap -- tim(a)klingt.org http://tim.klingt.org Cheat your landlord if you can and must, but do not try to shortchange the Muse. It cannot be done. You can't fake quality any more than you can fake a good meal. William S. Burroughs

3 8

Phoenix3 port to proto complete
by Thomas Heller 29 Jul '10

29 Jul '10

Ladies and Gentlemen, I proudly announce that the port of phoenix3 is completed! All testcases pass! (some with minor modifications) So, What is next? Here is my proposed schedule: - fix some minor issues - improve boost.bind compatibility: make all boost.bind testcases pass - implement all boost.lambda testcases and make them pass, as far as it is reasonable - add support for C++0x lambdas - make interoperability testcases for std::function, boost::function - adapt the documentation - clean up code (some parts are a little messy as of now) - improve compile time Did I miss something? This is a very tight schedule, I may not be able to finish all points during the GSoC period. Any help will be appreciated. Additionally a review of the current code is highly appreciated to point out some defects that might exist. The code can be checked out at: https://svn.boost.org/svn/boost/sandbox/SOC/2010/phoenix3 I will be happy to answer your questions! Additionally I would like to thank Joel de Guzman and Eric Niebler for their great assistance and initial designs! Best Regards, Thomas Heller

16 37

review request for boost.context
by Oliver Kowalke 29 Jul '10

29 Jul '10

Hello John, hello Ronald, could you add boost.context to the review queue please. boost.context allows to switch between execution contexts. The state of the context which will be left is saved and maybe resumed later. It is a kind of POSIX ucontext (fallback on POSIX platforms for boost.context) but provides assembler for some platforms (faster and some platforms doesn't implement POSIX ucontext because it is deprecaded -> ARM). thanks an best regards, Oliver

10 29

[Boost] [Thread] Query: Stack Size
by Alapkumar Sinha 29 Jul '10

29 Jul '10

Hi, How can I change the default stack size for each new thread being created? Secondly is there a mechanism to set the stack size while creation? I read somewhere that the default stack size is 8MB which is heavy for my application. Please suggest. Regards, Alap ________________________________ This Email may contain confidential or privileged information for the intended recipient (s) If you are not the intended recipient, please do not use or disseminate the information, notify the sender and delete it from your system. ______________________________________________________________________

3 4

[Interprocess] Query on Message queue
by Alapkumar Sinha 29 Jul '10

29 Jul '10

Hi, I have a requirement to have message type based receiving functionality, like the one provided by linux ipc "ssize_t msgrcv(int msqid, struct msgbuf *msgp, size_t msgsz, long msgtyp, int msgflg); " But the messagequeue implementation in boost only allows to set a priority of the message and does not provide a mechanism to wait on a messagequeue based on message type. Can someone tell me if there is a way out to get the above functionalities through boost as well. Regards, Alap ________________________________ This Email may contain confidential or privileged information for the intended recipient (s) If you are not the intended recipient, please do not use or disseminate the information, notify the sender and delete it from your system. ______________________________________________________________________

1 0

[serialization] Padding for base64 dataflow iterators ?
by Timothy Madden 29 Jul '10

29 Jul '10

Hello Could the documentation page for dataflow iterators in the serialization library please state that: 1. using base64 iterators will /not/ add the padding '=' characters in the encoded data, that are present in the canonical encoding in RFC4648 (The Base16, Base32, and Base64 Data Encodings) ? 2. binary string to be encoded should be null-terminated, or the iterators will not pad the input stream of bits with 0s to reach a multiple of 6 bits, but rather use whatever bits follow after the last encoded byte in memory ? Just so the user knows she either has to ensure padding, or otherwise she should not expect the result to exactly follow the RFC, and the result might not be suitable for data interchange between applications, etc ... Or maybe the examples could be changed to include padding, which would be even better ... :) Thank you, Timothy Madden

2 2

[placeholders]
by Andrzej Krzemienski 29 Jul '10

29 Jul '10

Hi, I have a problem with Boost.Bind placeholders. Namely, once I include the <boost/bind.hpp> it automatically brings placeholders _1, _2, .. into scope and I cannot use placeholders from other libraries like Spirit.Qi any more. I.e. I can but I need to qualify them like qi::_1, qi::_2, which is annoying. I include <boost/bind.hpp> in a precompiled header, so I have no option of not including it. Boost.Bind could define them in namespace boost::bind_placeholders and we could control their visibility with namespace using directive. This is what Spirit does, and it is cute. I guess I would not be able to convince anyone that Bind should do the same. But would it be possible to define placeholders _1, _2, ... as something more generic in Boost, unrelated to any particular library? Then boost::bind, would treat it as its own placeholders, Spirit semantic actions would treat them as its own placeholders, but they would be exactly same placeholders. Regards, &rzej

5 5

[interprocess] cmake files on trunk
by Eric Niebler 28 Jul '10

28 Jul '10

Looks like some CMake build files were inadvertently committed to boost trunk (changeset https://svn.boost.org/trac/boost/changeset/64331) I say "inadvertent" because there's no way these files can work in isolation, considering that all other CMake support has been removed from boost trunk. Ion, can you please remove these files? Thanks, -- Eric Niebler BoostPro Computing http://www.boostpro.com

1 0

thread_safe_ptr class interest request
by Philippe Vaucher 28 Jul '10

28 Jul '10

Hello, I've made a thread_safe_ptr class available at http://codepad.org/PxDEGaFm The idea is to use it like so: std::string data = "Hello world;"; thread_safe_ptr<std::string> data_ptr(&data); void thread1() { data_ptr->resize(3); } void thread2() { *data_ptr = "yeah"; } boost::thread t1(&thread1); boost::thread t2(&thread1); t1.join(); t2.join(); Do you see an obvious show-stopper for me not to continue developping this class? What's still to be done is worry about ownership of objects, my idea is to eventually somewhat model it after boost::shared_ptr that way it's easier to pass those around. When I'll be satisfied with the result, my plan is to "boostify" it (namespaces, license etc) and maybe propose it for inclusion in the smart pointer library. What are your thoughts? Philippe

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