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Thread safety of smart pointers?
by divick kishore 25 Mar '06

25 Mar '06

Hi, I have several questions related to boost. 1. Are boost::smart pointers thread safe especially shared_ptr ? Although it seems but I still want to be sure of that. 2. Why isn't there two flavours of every smart pointers, one with multithread safety and one without. If one is using some smart pointers in non threaded mode, then still does one need to pay the penalty for exclusive access ? What this means is that for example when one is using shared_ptr which I assume is implemented as counted pointer, any count increment or decrement has to be lock protected in multi-threaded case, which will be an overkill if one is using shared_ptr in a non multi-threaded code. 3. To enable multi-thread safety for other various libraries especially which are non-templates, does one need to compile boost with some special flags passed to the bjam? I am not sure whether this question is suited for this mailing list or not. Correct me if this is not the correct platform for posting this question. Thanks, Divick __________________________________________________________ Yahoo! India Matrimony: Find your partner now. Go to http://yahoo.shaadi.com

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Serialization library question
by wayne.x.liu＠jpmchase.com 25 Mar '06

25 Mar '06

I am trying to use the serialization library to serialize and instantiate polymorphic objects. I succeeded when serializing and deserializing the exact objects or using the exact pointer type of the derived classes. However, I failed when serializing and deserializing using a pointer to the base class. I would get either unregistered void cast or stream error or compilation errors or segementation faults. Perhaps I'm not understanding it correctly, but I believe the library is supposed to allow this. I saw the demo.cpp program is doing just that (de/serializing using pointers to bus_stop, the base class). I tried to narrow down my problem by stripping out demo.cpp to just the portion that serializes using pointers (removing gps, schedules, routes). However, doing this caused the program to stop compiling: incomplete type `boost::STATIC_ASSERTION_FAILURE< false>' The example seems very simple now. I tried to just remove the unnecessary classes. (I moved the ia.register_type(static_cast<bus_stop_corner *>(NULL)); into the save and restore routines.) I'm very confused how this very simple case doesn't work. Any help is greatly appreciated. Below is the stripped-down demo.cpp and the error message I got from gcc 3.2.3 and gcc 3.4.4. Thanks, Wayne Liu g++ -c -Wall -g -Iincludes -I/cbb/public/wayne/build/include -I/cbb/public/wayne/build/include/boost-1_33_1/ -o lib/demo.o test/demo.cpp /cbb/public/wayne/build/include/boost-1_33_1/boost/archive/detail/oserializer.hpp: In function `void boost::archive::save(Archive&, T&) [with Archive = boost::archive::text_oarchive, T = const bus_stop*]': /cbb/public/wayne/build/include/boost-1_33_1/boost/archive/basic_text_oarchive.hpp:78: instantiated from `void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) [with T = const bus_stop*, Archive = boost::archive::text_oarchive]' /cbb/public/wayne/build/include/boost-1_33_1/boost/archive/detail/interface_oarchive.hpp:78: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = const bus_stop*, Archive = boost::archive::text_oarchive]' test/demo.cpp:123: instantiated from here /cbb/public/wayne/build/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:567: error: incomplete type `boost::STATIC_ASSERTION_FAILURE< false>' used in nested name specifier /cbb/public/wayne/build/include/boost-1_33_1/boost/archive/detail/oserializer.hpp:567: error: size of array has non-integral type `<type error>' /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8 // demo.cpp // // (C) Copyright 2002-4 Robert Ramey - http://www.rrsd.com . // Use, modification and distribution is subject to the Boost Software // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) #include <iomanip> #include <iostream> #include <sstream> #include <string> #include <boost/archive/tmpdir.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/utility.hpp> #include <boost/serialization/list.hpp> ///////////////////////////////////////////////////////////// // One bus stop // // illustrates serialization of serializable members // class bus_stop { friend class boost::serialization::access; friend std::ostream & operator<<(std::ostream &os, const bus_stop &gp); virtual std::string description() const = 0; int latitude; int longitude; template<class Archive> void serialize(Archive &ar, const unsigned int version) { ar & latitude; ar & longitude; } protected: bus_stop(const int & _lat, const int & _long) : latitude(_lat), longitude(_long) {} public: bus_stop(){} virtual ~bus_stop(){} }; BOOST_IS_ABSTRACT(bus_stop) std::ostream & operator<<(std::ostream &os, const bus_stop &bs) { return os << bs.latitude << bs.longitude << ' ' << bs.description(); } ///////////////////////////////////////////////////////////// // Several kinds of bus stops // // illustrates serialization of derived types // class bus_stop_corner : public bus_stop { friend class boost::serialization::access; std::string street1; std::string street2; virtual std::string description() const { return street1 + " and " + street2; } template<class Archive> void serialize(Archive &ar, const unsigned int version) { // save/load base class information ar & boost::serialization::base_object<bus_stop>(*this); ar & street1 & street2; } public: bus_stop_corner(){} bus_stop_corner(const int & _lat, const int & _long, const std::string & _s1, const std::string & _s2 ) : bus_stop(_lat, _long), street1(_s1), street2(_s2) { } }; class bus_stop_destination : public bus_stop { friend class boost::serialization::access; std::string name; virtual std::string description() const { return name; } template<class Archive> void serialize(Archive &ar, const unsigned int version) { ar & boost::serialization::base_object<bus_stop>(*this) & name; } public: bus_stop_destination(){} bus_stop_destination( const int & _lat, const int & _long, const std::string & _name ) : bus_stop(_lat, _long), name(_name) { } }; void save(const bus_stop *s, std::stringstream &ss) { std::cout << "original"; std::cout << *s; boost::archive::text_oarchive oa(ss); oa.register_type(static_cast<bus_stop_corner *>(NULL)); oa.register_type(static_cast<bus_stop_destination *>(NULL)); oa << s; } void restore( std::stringstream &ss) { bus_stop *s; boost::archive::text_iarchive ia(ss); ia.register_type(static_cast<bus_stop_corner *>(NULL)); ia.register_type(static_cast<bus_stop_destination *>(NULL)); ia >> s; std::cout << "restored"; std::cout << *s; } int main(int argc, char *argv[]) { // fill in the data // make a few stops bus_stop *bs0 = new bus_stop_corner( 34, 134, "24th Street", "10th Avenue" ); bus_stop *bs1 = new bus_stop_corner( 35, 133, "State street", "Cathedral Vista Lane" ); bus_stop *bs2 = new bus_stop_destination( 35, 133, "White House" ); bus_stop *bs3 = new bus_stop_destination( 35, 133, "Lincoln Memorial" ); { std::stringstream ss; // display the complete schedule save(bs0,ss); restore(ss); } { std::stringstream ss; // display the complete schedule save(bs1,ss); restore(ss); } { std::stringstream ss; // display the complete schedule save(bs2,ss); restore(ss); } { std::stringstream ss; // display the complete schedule save(bs3,ss); restore(ss); } return 0; }

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Newbie: Boost for Windows"
by John Read 25 Mar '06

25 Mar '06

David Abrahams <dave_at_[hidden]> wrote: >That's a tough row to hoe. MinGW is a non-cygwin toolset. If you try >to build bjam under cygwin, you'll get a cygwin version of bjam. I >suggest you remove MinGW/bin from your path (maybe even uninstall >MinGW) and use the gcc-nocygwin toolset >(http://www.boost.org/tools/build/v1/gcc-nocygwin-tools.html) *or* you >give up on the cygwin environment and use the MinGW toolset from a >regular windows command prompt. It is not cygwin per se. I simply would like a proper shell to do my work in. Would using the MSYS command prompt make my row any less rocky? Also, when I use a DOS prompt and run build.bat from the jam_src directory, I seem to use the msvc toolset. This generates a bin.ntx86 directory with a bjam.exe. Looks like I am still not getting the toolset pointing to the gcc compiler. Is there any doc on how to compile Boost using the MinGW toolset and the gcc compiler on windows (preferably with some useable shell, not the DOS prompt)? If no, I will be glad to document this for us all when I get it sorted. Thanks, John --------------------------------- Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ countries) for 2¢/min or less.

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Re: [Boost-users] [LAMBDA] minimal installation
by Sohail Somani 25 Mar '06

25 Mar '06

Have you tried using bcp (http://www.boost.org/tools/bcp/bcp.html)? Sorry for top-posting, but when I get html emails, outlook looks out. -----Original Message----- From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Andreas Sæbjørnsen Sent: Friday, March 24, 2006 3:21 PM To: boost-users(a)lists.boost.org Subject: [Boost-users] [LAMBDA] minimal installation Since we are interested in using Boost::Lambda in our project and can not depend on the whole of the Boost library because of size restrictions we are interested in including a minimum Lambda subset of Boost. From what I understand only header files are needed in order to use Lambda, so that leads me to believe such a subset should be possible. In an initial experiment I created such a subset, but was unable to make it smaller than 13.3mb. Is it possible to create a subset of Boost to use Lambda which would be around 1mb or less? If so, has anybody already created such a subset? 4096 Mar 24 12:34 config 2050 Mar 24 12:31 config.hpp 4096 Mar 24 12:34 detail 1039 Mar 24 12:33 indirect_reference.hpp 4096 Mar 24 12:34 iterator 4096 Mar 24 12:24 lambda 4096 Mar 24 12:31 mpl 1821 Mar 24 12:34 pointee.hpp 4096 Mar 24 12:34 preprocessor 3626 Mar 24 12:33 ref.hpp 4523 Mar 24 12:33 static_assert.hpp 7844 Mar 24 12:33 static_warning.hpp 4096 Mar 24 12:34 tuple 4096 Mar 24 12:28 type_traits 4096 Mar 24 12:34 utility 13344MB Thanks Andreas Saebjoernsen

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I can't get signals library statically linked
by Marco Cecchetti 24 Mar '06

24 Mar '06

Hi, I've the following problem: I'm using in a program the boost signals library. I compile and link the program with the command below: "g++ -static -o sig.exe -g2 -O0 -I<path to boost include files> -L<path to boost libs> main.cpp -lboost_signals-mgw-d" and I've put the line : "#define BOOST_SIGNALS_STATIC_LINK" in my source code. I'm under the windows platform and I'm using mingw (gcc 3.4.2) and boost 1.33.1 . The program compiles and links without any error but when I try to run it a dialog window says to me that the application has failed to start because "boost_signals-mgw-1_33_1.dll" was not found. It seems that the signal library is not linked statically but I don't succeed in figuring out the reason of this behavior. If I add to the PATH variable the path to the boost libs the program runs properly but I need to get the signal library statically linked, so some help will be very usefull. -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

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Large boost::multi_array Problem
by Adam Hartshorne 24 Mar '06

24 Mar '06

Hi, I have the following problem, I make a boost::multi_array<float,2> of size X by X. I initialise this using the following line typedef boost::multi_array<float, 2> array_type; array_type D(boost::extents[num_vertices][num_vertices]); This works fine up to a size of 5000 x 5000 then my program crashes at the definition stage due to memory requirements. I am assuming the boost::extents call stops my program creating a multi array of a size bigger than 5000 x 5000. However in certain situations I need a bigger 2D array, any thoughts on how I can achieve this? Adam

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Re: [Boost-users] [date_time] How to create a date from string withspecific format?
by Andrew Holden 24 Mar '06

24 Mar '06

> -----Original Message----- > From: Christian Henning [mailto:chhenning@gmail.com] > Sent: Tuesday, March 21, 2006 4:23 PM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] [date_time] How to create a date from string > withspecific format? > > Hi Dean, thanks for the answer. > > Since, I know the format of the date strings I could also use > boost::regex for the general format and then feeding a date object > with the values. If I get an exception during the date object > contruction I know that the user provided me with garbage. > > > Any thoughts on that? > > Thanks again, > Christian Have you considered using Regex's submatches? A slightly modified example follows. // date format: mm-dd-yyyy boost::regex oDateReg( "(\\d{2})-(\\d{2})-(\\d{4})" ); std::string strDate( "11-33-1997" ); boost::smatch dateMatch; if( boost::regex_match( strDate , dateMatch , oDateReg )) { try { std::string strMonth = dateMatch[1]; std::string strDay = dateMatch[2]; std::string strYear = dateMatch[3]; unsigned int nYear = boost::lexical_cast<unsigned int>(strYear); unsigned int nMonth = boost::lexical_cast<unsigned int>(strMonth); unsigned int nDay = boost::lexical_cast<unsigned int>(strDay); date d( nYear, nMonth, nDay ); date::ymd_type ymd = d.year_month_day(); } catch( std::out_of_range oEx ) { std::cout << "Error: " << oEx.what() << std::endl; } } There are two advantages to this. First, you no longer need to count characters when extracting the date components. Second, you have a little more freedom in defining your date format. For example, you could use the following definition for oDateReg to also accept single-digit months and/or days: boost::regex oDateReg( "(\\d{1,2})-(\\d{1,2})-(\\d{4})" ); Andrew Holden

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typecasting a boost::shared_ptr ?
by Dhanvi Kapila 24 Mar '06

24 Mar '06

Hi Friends, I have a boost::shared_ptr that stores a pointer to a base class ( class B1 ) and derived classes ( class D1 , class D2 ) both inheriting from the same Base class. The Constructors I have another set of factory classes ( base class : class base1, derived class : class derv1 & class derv2 ) whoose constructors accepts boost::shared_ptr of B1. When constructing derv1: I would like to cast pointer as D1 and ,when constructing derv2 : cast pointer as D2, but the only way I can access the class functions is through a shared_ptr to B1. My question is how do I cast B1 to get D1 and D2 in the constructors for derv1 and derv2 respectively ? the pseudo code is base1* createBase( boost::shared_ptr<B1> b_ptr , int type ) { if( type == 1 ) return new derv1( boost::polymorphic_downcast<AAAA> b_ptr ); else return new derv2( boost::polymorphic_downcast<XXXX> b_ptr ); } what do i write in the place of AAAA & XXXX for the code to wrk ?? Sorry for the long question, but could not express it in any shorter way.. thanks for ur patience and replies Dhanvi

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Building multi-architecture on Mac OS X (Darwin)
by Ken Anderson 24 Mar '06

24 Mar '06

I'm trying to determine the proper command line parameters to build boost universal (i386 & ppc) on a Mac OS X machine. Can anyone give me any recommendations? I need to have this passed to the compiler and linker: -arch i386 -arch pcc Thanks, Ken

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Re: [Boost-users] [iostreams] inverse and "stateful" filters
by EMalenfant＠interstarinc.com 24 Mar '06

24 Mar '06

From: EMalenfant(a)interstarinc.com > Consider the following, using dictionary_output_filter from > the tutorial: > (http://www.boost.org/libs/iostreams/doc/index.html?path=2.2.6.3) > > namespace io = boost::iostreams; > > const std::string source("This foo will be bar"); > > io::example::dictionary dict; > dict.add("foo", "bar"); > > io::filtering_istream in; > in.push(io::invert(io::example::dictionary_output_filter(dict))); > in.push(io::array_source(source.c_str(), source.length())); > > io::copy(in, std::cout); > > Output: > This bar will be > > instead of the expected: > This bar will be bar > Digging a bit, I found that I could "fix" that problem by modifying invert::read() as follows: template<typename Source> std::streamsize read(Source& src, char* s, std::streamsize n) { typedef detail::counted_array_sink<char_type> array_sink; typedef composite<filter_ref, array_sink> filtered_array_sink; assert((flags() & f_write) == 0); if (flags() == 0) { flags() = f_read; buf().set(0, 0); } filtered_array_sink snk(filter(), array_sink(s, n)); int_type status; for ( status = traits_type::good(); snk.second().count() < n && status == traits_type::good(); ) { status = buf().fill(src); buf().flush(snk); } // "Fix": When eof is reached on the input, close the filter so that it writes // any buffered input it may have. if ((snk.second().count() == 0) && (status == traits_type::eof())){ snk.close(); } //... "fix" ends here return snk.second().count() == 0 && status == traits_type::eof() ? -1 : snk.second().count(); } Looking at this, however, I wondered what would happen if the filter has buffered more characters than what would fit in the array_sink. So I tested with a very long (around 300) last word in the input. Result: An infinite loop in non_blocking_adapter::write(), desperately calling write() on a full counted_array_sink. Guess I'll forget about invert and write an InputFilter...

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