April 2010 - Boost-users - lists.preview.boost.org

Re: [Boost-users] [Bind] Unexpected behavior when bindingconstchar* to function
by Pete Bartlett 29 Apr '10

29 Apr '10

Piotr Jachowicz wrote: >I only wanted to express concern that when binding to function >accepting pointers (which is misuse) No, its not misuse to pass a pointer to bind. You'd just have to remember if the pointed-to object changes prior to calling the function call operator of the binder, then you end up using the changed object in your function call. But there is nothing at all special about Bind here. Consider struct T { int something(){ /*some state-dependent calculation here*/ } void change_me(){ /*change state here*/ } }; struct A { T* t; int foo(){ return T->something(); } }; int main() { T myT(...); A a; a.t = &myT; myT.change_me(); return a.foo(); //the changes in "change_me" matter here } This is all "pointers 101", so why pick on Bind? Pete

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[filesystem] Custom memory allocator
by Dominic Vandot 28 Apr '10

28 Apr '10

All, I'd like to use filesystem::path with a custom memory allocator (I need to allocate and free millions of paths in cycles from multiple threads). As far as I understand only the underlying string type can have a custom allocator. I created these typedefs: typedef basic_string<char, char_traits<char>, tbb::scalable_allocator<char> > fast_string; struct fast_path_traits; typedef fs::basic_path<fast_string, fast_path_traits> fast_path; struct fast_path_traits { typedef fast_string internal_string_type; typedef fast_string external_string_type; static external_string_type to_external( const fast_path &, const internal_string_type & src ) { return src; } static internal_string_type to_internal( const external_string_type & src ) { return src; } }; typedef basic_directory_iterator<fast_path> fast_directory_iterator; Everything compiles until the point where I'd use operations: d = file_size<fast_path>(itr->path()); I get this error under VS2009: error C2770: invalid explicit template argument(s) for 'boost::enable_if<boost::filesystem::is_basic_path<Path>,boost::uintmax_t>::type boost::filesystem::file_size(const Path &)' Please help correcting it. Thanks, Dominic

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Class from plugin serialization fails
by Icek 28 Apr '10

28 Apr '10

Hi, I'm using boost::serialization to store my data from my application. Everything is working nice, but I just can't store my class loaded from plugin. I know there is a lot of discussion here on this topic, I did read a lot of it. I also looked in /examples and /test directories but I still don't fully understand what exactly should I do... So I have abstract class i main application and derived class in plugin. As I understand it, all I have to do to make it work is: 1) #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> 2) use BOOST_CLASS_EXPORT macro in plugin_class.cpp but I'm still getting unregistered class exception. Can someone help me please? I know I'm doing something wrong but I can't figure it out. I'm running Ubuntu Lucid with boost 1.40... -- View this message in context: http://old.nabble.com/Class-from-plugin-serialization-fails-tp28380080p2838… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Test] prevent exceptions from beeing caught
by Jan Rudoszanski 28 Apr '10

28 Apr '10

Hi Is there any possibility for boost.test execution_monitor to not to catch exceptions thrown from code that I'm examining in a test case? It's the case with system errors which you can pass from execution monitor outside, to the system for further examination in debugger (--catch_system_errors=n). How am I supposed to do the same with regular exceptions i.e. detect where an exception comes from, if only information I get is something like "unknown location(0): fatal error in testValidate" etc? I would love to have possibility to detect this exception with debugger and print full stack trace, examine variables and so on. Is it possible with boost.test? Regards.

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[ANN] CodeSynthesis XSD 3.3.0 released
by Boris Kolpackov 28 Apr '10

28 Apr '10

Hi, I am pleased to announce the availability of CodeSynthesis XSD 3.3.0. CodeSynthesis XSD is an open-source (GPL2 + proprietary license), cross- platform W3C XML Schema to C++ data binding compiler. Provided with a schema, it generates C++ classes that represent the given vocabulary as well as parsing and serialization code. You can then access the data stored in XML using types and functions that semantically correspond to your application domain rather than dealing with elements, attributes, and text in a direct representation of XML such as DOM or SAX. The XSD compiler uses several Boost libraries (filesystem and regex) in its implementation. The generated code can also map XML Schema date/time built- in types to Boost date_time types. The C++ classes can also be serialized into various binary formats besides XML. Boost serialization library is supported as one of the representations. Major new features in this release: * Support for uniform parsing and serialization of XML documents with varying root elements. * Configurable application character encoding (UTF-8, ISO-8859-1, etc). * Support for stream-oriented, partially in-memory/partially event- driven XML parsing and serialization. * Support for embedding the binary representation of the schema grammar into the application. * Generation of the detach functions that allow moving object model sub-trees without copying. * Support for XML compression. * Smaller and faster generated code for polymorphic XML Schemas (xsi:type and substitution groups). The release also adds support for a range of new operating system and C++ compiler versions, including: * AIX 6.x * Mac OS X 10.6 * Windows 7, * Windows Server 2008 * Visual Studio 2010 (10.0) * GNU g++ 4.5.0 * Intel C++ 11 * Sun Studio 12.1 * IBM XL C++ 11 Visual Studio 2010 project and solution files are provided for all the examples. For the complete list of new features in this release see: http://www.codesynthesis.com/pipermail/xsd-announcements/2010/000038.html CodeSynthesis XSD is available on IBM AIX, GNU/Linux, HP-UX, Mac OS X, Solaris, Windows, OpenVMS, and z/OS. Supported C++ compilers include: GNU g++, HP aCC, IBM XL C++, Intel C++, Sun C++, and MS Visual C++. More information, documentation, source code, and precompiled binaries for all the supported platforms are available from: http://www.codesynthesis.com/products/xsd/ Boris -- Boris Kolpackov, Code Synthesis http://codesynthesis.com/~boris/blog Open-source XML data binding for C++ http://codesynthesis.com/products/xsd XML data binding for embedded systems http://codesynthesis.com/products/xsde Command line interface to C++ compiler http://codesynthesis.com/projects/cli

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boost-build forum?
by Steve Jaffe 28 Apr '10

28 Apr '10

I have a bjam question I tried posting to boost-build but it's been waiting for the moderator for 18 hours. It looks like very few questions get through -- none yesterday for instance. Two questions: 1. Is boost-build list active? 2. Is it appropriate to post bjam questions to boost-users, or is there another more appropriate list? Thanks -- View this message in context: http://old.nabble.com/boost-build-forum--tp28387976p28387976.html Sent from the Boost - Users mailing list archive at Nabble.com.

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asio::local::stream_protocol difficulties
by boost＠hannes.oib.com 28 Apr '10

28 Apr '10

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[Proto] Higher order function
by noman javed 27 Apr '10

27 Apr '10

Hi I have just started experimenting with proto. I have the following grammer G ::= Apply f G | Arrray where the code of the simple array and apply classes are given below: How can I transform this code in the proto template<typename T> class Array { public: Array(int size) : size(size) { data = new T[size]; } operator=() { ... } private: int size; T* data; }; I have another class apply that applies the function (its first argument) on its other arguments template<typename F, typename EXP> struct apply { Array<typename F::result_type>& operator()(EXP & exp) { ... } typename F::result_type operator[](typename F::input_type i) { return f(i); } }; The Apply class can be a unary or binary or infact an n-ary class. How can I protofy this expression template? Regards Noman Javed Orléans, France

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[Bind] Unexpected behavior when binding const char* to function
by Piotr Jachowicz 27 Apr '10

27 Apr '10

Hello, This code proceces "xyz", contrary to user intention to bind "abc": void echo(const char* s) { cout << s << '\n'; } int main() { string s("abc"); function<void ()> f = boost::bind(echo, s.c_str()); s = "xyz"; f(); } This is misleading. Changing "echo(const char*)" into "echo(string)" produces "abc", as expected. Is there any way (other than echo wrapper) to get "abc" as expected? -- Piotr Jachowicz

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[boost-users][proto] Using proto with nvcc
by Manjunath Kudlur 27 Apr '10

27 Apr '10

I noticed that fix for ticket #3919 has been checked-in. Thanks JoelF. I checked out boost trunk, and am trying to compile the following simple program using nvcc. #include <boost/proto/proto.hpp> namespace proto=boost::proto; int main() { return 0; } I was getting "ISO C++ forbids declaration of ‘expr_param’ with no type" error in couple of places in proto/traits.hpp and proto/transform/pass_through.hpp. The code used to look like typename pass_through_impl::expr_param e I added a typedef as follows transform_impl<Expr, State, Data> base_type; and changed the code to typename base_type::expr_param e Now the compiler error goes away. I have 2 questions : 1) Is what I am doing the right fix for the problem, or is the nvcc compiler really broken when handling this? 2) If my fix is OK, how do I make it permanent? The other error I am seeing is probably not proto's problem, but I will mention it here anyway : boost/boost-trunk/boost/mpl/size_t_fwd.hpp:23: error: expected unqualified-id before ‘[’ token boost/boost-trunk/boost/mpl/size_t_fwd.hpp:26: error: ‘mpl_::size_t’ has not been declared boost/boost-trunk/boost/mpl/aux_/integral_wrapper.hpp:42: error: expected unqualified-id before ‘[’ token Any ideas on this? Thanks, Manjunath http://nonchalantlytyped.net/blog/musings/

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