January 2009 - Boost-users - lists.boost.org

Comparing is_pointer with true_
by jean-louis.a.leroy＠fortis.com 19 Jan '09

19 Jan '09

Hello. I need to compare is_const<T> with true_ or false_. I don't find an easy way to do it. I have tried: void foo(mpl::true_) { cout << "true" << endl; } void foo(mpl::false_) { cout << "false" << endl; } int _tmain(int argc, _TCHAR* argv[]) { foo(is_same< mpl::true_, is_pointer<void*>() >()); foo(is_same< mpl::true_, is_pointer<void*>::type() >()); foo(is_convertible< is_pointer<void*>(), mpl::true_ >()); foo(is_base_of< mpl::true_, is_pointer<void*>() >()); return 0; } (in case you wonder why I don't simply pass is_pointer to foo(), here's why: I have a function object that is called twice with a bool_ template argument; the first time it handles all non-pointer types and in a second pass it handles the pointer types; in fact I'm trying to implement the equivalent of b1 == b2, where b1 and b2 are bools). I understand that is_pointer<T> derives either from true_type or false_type. Thus it's normal that is_same fails. But what of the others? Jean-Louis = = = = = = = = = = = = = = = = = = = = = = = = = Fortis disclaimer : http://www.fortis.be/legal/disclaimer.htm Privacy policy related to banking activities of Fortis: http://www.fortis.be/legal/privacy_policy.htm = = = = = = = = = = = = = = = = = = = = = = = = =

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Re: [Boost-users] problems installing boost -- explorer.exe
by Marks, Joseph 19 Jan '09

19 Jan '09

For what it's worth, I have had a similar problem with the "7z" or 7-zip program. I had to re-install this program this morning, as it was "acting" up. I don't know what you're using for zips -- WinZip, 7-zip, j-zip, or some other program, but the problem *could* be with that software; then again, it might not. ADMG Joseph

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problems installing boost -- explorer.exe Application error
by Paul Epstein 19 Jan '09

19 Jan '09

I have been trying to install the latest version of Boost from sourceforge.net. I have a Windows Vista operating system. I downloaded the boost.zip file and the boost-jam.zip file. I was able to extract the boost-jam file without problems. However, whenever I try and extract the boost.zip file to a folder I created I get the message: explorer.exe - Application Error The exception unknown software exception (0xc000000d) occurred in the application at 0x75afc02c. I tried ending the process explorer.exe, but when I kill that process, I am unable to do the extracting. I know this is a basic problem. I doubt that the issue is specifically Boost-related but since the problem arose in a boost-context, I'm hopefully on topic. Many thanks for your help. Paul Epstein

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Building iostreams with zlib support on Windows XP in mingw-msys
by e m 19 Jan '09

19 Jan '09

I use bjam like so: bjam toolset=gcc link=static runtime-link=static threading=single \ --with-iostreams --with-filesystem \ -sNO_COMPRESSION=0 -sNO_ZLIB=0 -sZLIB_SOURCE=C:/zlib123 \ --build-type=release install -------------------------------------------------- But, I do not believe that zlib is being built or linked in to iostreams. The only libs I get in C:/Boost/lib after bjam are these: libboost_filesystem-mgw34-s.lib libboost_system-mgw34-s.lib libboost_iostreams-mgw34-s.lib However, the output from bjam does not indicate any errors with iostreams or zlib. -------------------------------------------------- When I try to compile the zlib example from here: http://www.boost.org/doc/libs/1_37_0/libs/iostreams/doc/classes/zlib.html#e… I get these errors: C:/Users/e4m/AppData/Local/Temp/ccSscQ9O.o:zlib_test.cpp:(.text$_ZN5boost9iostreams6detail22zlib_decompressor_implISaIcEED2Ev[boost::iostreams::detail::zlib_decompressor_impl<std::allocator<char> >::~zlib_decompressor_impl()]+0x58): undefined reference to `boost::iostreams::detail::zlib_base::reset(bool, bool)' C:/Users/e4mAppData/Local/Temp/ccSscQ9O.o:zlib_test.cpp:(.text$_ZN5boost9iostreams6detail22zlib_decompressor_implISaIcEED2Ev[boost::iostreams::detail::zlib_decompressor_impl<std::allocator<char> >::~zlib_decompressor_impl()]+0x6a): undefined reference to `boost::iostreams::detail::zlib_base::~zlib_base()' ... ... ... -------------------------------------------------- I am trying to compile the example like this: g++ -static -O3 zlib_test.cpp -o zlib_test.exe -Ic://Boost/include/boost-1_37/ c://Boost/lib/libboost_iostreams-mgw34-s.lib -------------------------------------------------- Here is the example source code as I have modified it slightly while experimenting: #include <fstream> #include <iostream> #include <boost/iostreams/filtering_streambuf.hpp> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/filter/zlib.hpp> //#include "C:/boost_1_37_0/boost_1_37_0/libs/iostreams/src/zlib.cpp" #define BOOST_IOSTREAMS_NO_LIB int main() { using namespace std; using namespace boost::iostreams; ifstream file("hello.z", ios_base::in | ios_base::binary); filtering_streambuf<input> in; in.push(zlib_decompressor()); in.push(file); boost::iostreams::copy(in, cout); return 0; } -------------------------------------------------- I've googled a lot for the last week trying to figure out what I'm doing wrong, to no avail... Can someone help me? Thanks, e

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[fusion - I think!] Multiple nested range traversal.
by Robert Jones 19 Jan '09

19 Jan '09

I recently asked a question on here about traversal of multiple indices, which produced a luke-warm reaction, mainly because I wasn't really asking the right question! So here's another try. Consider a bit of code like this for ( unsigned i=0; i!=3; ++i ) for ( unsigned j=2; j!=5;++j ) for ( unsigned k=4;k!=10;++k ) f( i, j, k ); I'd guess this comes up pretty often, and by generalising it to * an arbitrary number of ranges, of arbitrary types * f() implemented as a lambda or bind function would have quite wide applicability. I've considered writing an implemetation, which has dragged me into examining fusion and mpl in some detail, but doing so does not seem to me be trivial at all. Is there already something in Boost which does this? Thanks, Rob.

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[boost-users][serialization]
by Igor R 19 Jan '09

19 Jan '09

Hello, I've just started to use serialization in my project. When I try to save some struct into archive: boost::archive::xml_oarchive archive = ....; archive << BOOST_SERIALIZATION_NVP(descriptor_); ...the following error occures (boost 1.36.0, MSVC9.0SP): boost/serialization/level.hpp(54) : error C2039: 'basic_traits' : is not a member of 'boost::serialization::boost::serialization' What does it mean in terms of my code, i.e. where should I look for an error? Thank you.

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[Variant] Odd linker errors that somehow involve boost::variant
by James Madison 19 Jan '09

19 Jan '09

[NOTE : this is using boost v1.32. I am forced to use this version] In the code I am trying to compile I have a boost variant defined as: boost::variant<int, char, double, std::string, ACE_Time_Value> and it is used in several different ways. This project compiles and links fine using debug settings, essentially the -g flag in gcc, however whenever I try to compile without that flag I get the following error, repeated hundreds of times: `.gnu.linkonce.t._ZNSt3mapIiN5boost7variantIicdSs14ACE_Time_ValueNS0_6detail7variant5void_ES5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_EESt4lessIiESaISt4pairIKiS6_EEEixERSA_' referenced in section `.gnu.linkonce.r._ZNSt3mapIiN5boost7variantIicdSs14ACE_Time_ValueNS0_6detail7variant5void_ES5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_EESt4lessIiESaISt4pairIKiS6_EEEixERSA_' of ./src/geneva/infra/messaging/ResponseMsg.o: defined in discarded section `.gnu.linkonce.t._ZNSt3mapIiN5boost7variantIicdSs14ACE_Time_ValueNS0_6detail7variant5void_ES5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_EESt4lessIiESaISt4pairIKiS6_EEEixERSA_' of ./src/geneva/infra/messaging/ResponseMsg.o Google is not helping diagnose the problem at all. I am wondering if anyone here can point me in the right direction.

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Problem with shared_ptr
by Germán Diago 18 Jan '09

18 Jan '09

What's wrong with this code? When I push_back ptr to the vector, it pushes 0 instead of the value contained in ptr (which I checked and is non-zero). std::vector<boost::shared_ptr<BaseClass> > baseobjects = get_base_objects(path); std::vector<boost::shared_ptr<DerivedClass> > result(get_base_objects.size()); BOOST_FOREACH (boost::shared_ptr<BaseClass> en, baseobjects) { boost::shared_ptr<DerivedClass> ptr = boost::dynamic_pointer_cast<DerivedClass>(en); //Error when push_back. Instead of ptr, I get 0 result.push_back(ptr); } Thanks.

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combining asio::serial_port with iostreams::stream
by Christoph Gysin 18 Jan '09

18 Jan '09

Hi boost users I'm a newbie to boost trying to use a serial port as an iostream. While searching the archives I found a post by Rob Desbois (2008-01-18 13:02) trying to achive the same. Unfortunately the solution wasn't posted. This is what I got so far: #include <boost/asio.hpp> #include <boost/iostreams/stream.hpp> class serial_device { public: typedef char char_type; typedef boost::iostreams::bidirectional_device_tag category; serial_device(boost::asio::io_service& io_service, const std::string& port, int baudrate = 9600) : serial_port(io_service, port) { typedef boost::asio::serial_port_base spb; serial_port.set_option(spb::baud_rate(baudrate)); }; std::streamsize read(char* buf, std::streamsize n) { boost::asio::read(serial_port, boost::asio::buffer(buf, n)); } std::streamsize write(const char* buf, std::streamsize n) { boost::asio::write(serial_port, boost::asio::buffer(buf, n)); } private: boost::asio::serial_port serial_port; }; int main(void) { boost::asio::io_service io_service; serial_device serial(io_service, "/dev/ttyS0", 115200); //boost::iostreams::stream<serial_device> s(serial); } If I uncomment the last line it fails to compile: g++ -lboost_iostreams-mt -lboost_system-mt -lboost_thread-mt iostream.cpp -o iostream /usr/include/boost/noncopyable.hpp: In copy constructor 'boost::asio::basic_io_object<boost::asio::serial_port_service>::basic_io_object(const boost::asio::basic_io_object<boost::asio::serial_port_service>&)': /usr/include/boost/asio/basic_io_object.hpp:30: instantiated from 'boost::iostreams::stream<Device, Tr, Alloc>::stream(Device&, int, int) [with Device = serial_device, Tr = std::char_traits<char>, Alloc = std::allocator<char>]' iostream.cpp:36: instantiated from here /usr/include/boost/noncopyable.hpp:27: error: 'boost::noncopyable_::noncopyable::noncopyable(const boost::noncopyable_::noncopyable&)' is private /usr/include/boost/asio/basic_io_object.hpp:30: error: within this context /usr/include/boost/noncopyable.hpp: In copy constructor 'boost::asio::detail::reactive_descriptor_service<boost::asio::detail::epoll_reactor<false> >::implementation_type::implementation_type(const boost::asio::detail::reactive_descriptor_service<boost::asio::detail::epoll_reactor<false> >::implementation_type&)': /usr/include/boost/noncopyable.hpp:27: error: 'boost::noncopyable_::noncopyable::noncopyable(const boost::noncopyable_::noncopyable&)' is private /usr/include/boost/asio/detail/reactive_descriptor_service.hpp:47: error: within this context /usr/include/boost/asio/basic_io_object.hpp: In copy constructor 'boost::asio::basic_io_object<boost::asio::serial_port_service>::basic_io_object(const boost::asio::basic_io_object<boost::asio::serial_port_service>&)': /usr/include/boost/asio/basic_io_object.hpp:30: note: synthesized method 'boost::asio::detail::reactive_descriptor_service<boost::asio::detail::epoll_reactor<false> >::implementation_type::implementation_type(const boost::asio::detail::reactive_descriptor_service<boost::asio::detail::epoll_reactor<false> >::implementation_type&)' first required here /usr/include/boost/asio/basic_serial_port.hpp: In copy constructor 'boost::asio::basic_serial_port<boost::asio::serial_port_service>::basic_serial_port(const boost::asio::basic_serial_port<boost::asio::serial_port_service>&)': /usr/include/boost/asio/basic_serial_port.hpp:51: note: synthesized method 'boost::asio::basic_io_object<boost::asio::serial_port_service>::basic_io_object(const boost::asio::basic_io_object<boost::asio::serial_port_service>&)' first required here iostream.cpp: In copy constructor 'serial_device::serial_device(const serial_device&)': iostream.cpp:5: note: synthesized method 'boost::asio::basic_serial_port<boost::asio::serial_port_service>::basic_serial_port(const boost::asio::basic_serial_port<boost::asio::serial_port_service>&)' first required here /usr/include/boost/iostreams/stream.hpp: In constructor 'boost::iostreams::stream<Device, Tr, Alloc>::stream(Device&, int, int) [with Device = serial_device, Tr = std::char_traits<char>, Alloc = std::allocator<char>]': /usr/include/boost/iostreams/stream.hpp:129: note: synthesized method 'serial_device::serial_device(const serial_device&)' first required here make: *** [iostream] Error 1 Could anyone please explain what I'm doing wrong? Thanks, Chris -- echo mailto: NOSPAM !#$.'<*>'|sed 's. ..'|tr "<*> !#:2" org@fr33z3

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[program_options] Can you use position-sensitive parameters?
by Adam Nielsen 18 Jan '09

18 Jan '09

Hi all, I can't find anything in the docs that tells me whether this is possible without writing custom parsers etc. so if anyone knows whether this can be done please let me know. I'd like to be able to use position-sensitive parameters. For example, a program to work with .zip files: zip --rename=one.bin:alpha.bin --add=one.bin --rename=one.bin:beta.bin Using this example, the initial --rename would need to be acted upon first, before -add (otherwise one.bin would get overwritten) and likewise the last --rename must be acted upon after -add, otherwise the wrong file (or no file) would be renamed. If I use normal string vectors the order of the parameters will be lost so this won't work. Is this sort of parsing possible with program_options? Thanks, Adam.

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