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deepcpy_ptr
by gast128 06 Feb '05

06 Feb '05

Dear all, I couldn't find functionality a la deep copy pointer in boost. Isn't this an idea to extend the smart_ptr library with it? Basically it has the same functionality as if the object was hold by value, but sometimes you want to dismiss the header file and only have a fwd decl: #include "bla.hpp" struct Foo { Bla m_Bla; }; deep copy: class Bla; //fwd decl. is sufficient { deepcpy_ptr<Bla> m_ptr; }; Or do I overlook something? Wkr, me

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Re: Compiling boost on tru64 (Richard Hadsell)
by Mark Helzer 06 Feb '05

06 Feb '05

>Mark Helzer wrote: >>I'm getting this error trying to build boost >>tru64cxx65-C++-action >>bin/boost/libs/date_time/build/libboost_date_time.so/tru64 >>cxx65/debug/greg_month.o >>cxx: Error: /adp/local/src/boost_1_32_0/boost/cstdint.hpp, line 87: #5 >>could >> not open source file "inttypes.h" >> >>Quite true, it doesn't exist. >>Here's my command line: >>bjam -sTOOLS=tru64cxx65 install >> >>Compiler is >> >> >>cxx -V >> >> >>Compaq C++ V6.5-041 for Digital UNIX V4.0F (Rev. 1229) >>Compiler Driver V6.5-041 (cxx) cxx Driver >> >>Is this a configuration issue? >> >> >For now, remove '|| defined(__osf__)' from line 85 of cstdint.hpp. >There may be a more general fix in the current CVS version, but this >change works for me (and my 4.0F system). Kewl, that works, I got a little further down the path. Next problem: cxx: Error: /adp/local/src/boost_1_32_0/boost/bind.hpp, line 206: #266 "value" is ambiguous detected during: instantiation of class "boost::_bi::list1<A1> [with A1=boost::_bi::list_av_1<boost::arg<1>>::B1]" at line 161 of "/adp/local/src/boost_1_32_0/boost/bind/bind_template.hpp " instantiation of class "boost::_bi::bind_t<R, F, L> [with R=std::wstring, F=std::wstring (*)(const std::string &), L=boost::_bi::list1<boost::_bi::list_av_1<boost::arg<1>>: :B1>]" at line 71 of "/adp/local/src/boost_1_32_0/libs/program_options/build/. ./src/parsers.cpp" template<class T> T & operator[] (value<T> & v) const { return v.get(); } --------------------------------------^ I see value defined as a class template at line 90 of boost/bind.hpp

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linker problems with gcc 3.3.5 and 3.4.3
by Derek Scherger 06 Feb '05

06 Feb '05

Hi, I've recently started getting thousands of messages like the following, while linking with -lboost_regex -lboost_date_time -lboost_filesystem. /usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.5/../../../../i686-pc-linux-gnu/bin/ld: `.gnu.linkonce.t._ZN5boost2io6detail22parse_printf_directiveIcSt11char_traitsIcEN9__gnu_cxx17__normal_iteratorIPKcSsEENS0_16basic_outsstreamIcS4_EEEEbRT1_RKSC_PNS1_11format_itemIT_T0_EERT2_h' referenced in section `.rodata' of monotone-commands.o: defined in discarded section `.gnu.linkonce.t._ZN5boost2io6detail22parse_printf_directiveIcSt11char_traitsIcEN9__gnu_cxx17__normal_iteratorIPKcSsEENS0_16basic_outsstreamIcS4_EEEEbRT1_RKSC_PNS1_11format_itemIT_T0_EERT2_h' of monotone-commands.o Linking monotone (http://www.venge.net/monotone) produces ~5000 or so messages like this. I'm running on gentoo linux and I believe this started happening when I recently upgraded from gcc 3.3.4 to 3.3.5. Originally I was using boost 1.31.0 but I have tried upgrading to 1.32.0 and also upgrading gcc to 3.4.3. I have not yet tried downgrading gcc to 3.3.4 but that's pretty much next on the list. I really don't know for sure what is causing this, but it really is quite annoying. It could be gentoo's packaging of gcc or something else, or it could be gcc or boost, or ... I do see a few similar sounding posts such as http://www.mail-archive.com/lyx-devel@lists.lyx.org/msg74258.html but so far haven't been able to fix the problem. Any help or insight would be greatly appreciated. Cheers, Derek

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Linker Problem with Regex Libraries VC7
by Nicholas Cardi 06 Feb '05

06 Feb '05

The linker is complaining that it can't find the file libboost_regex-vc71-mt-sgd-1_32.lib This file was not built when I made the regex library. Here is the exsact linker error: fatal error LNK1104: cannot open file 'libboost_regex-vc71-mt-sgd-1_32.lib' The file libboost_regex-vc7-mt-sgd-1_32.lib does exist on my machine and it is in my include directory. >From the install document Finally when you use regex++ it is only necessary for you to add the <boost> root directory to your list of include directories for that project. It is not necessary for you to manually add a .lib file to the project; the headers will automatically select the correct .lib file for your build mode and tell the linker to include it. Is it possible the headers are referancing the wrong lib file? Thanks Nicholas Cardi

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(no subject)
by M L 05 Feb '05

05 Feb '05

unsub boost-users

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[variant] is_a/can_be
by Yuval Ronen 05 Feb '05

05 Feb '05

Hi. I encountered the need to query a boost::variant to which type it currently contain. I'm talking about something like: variant<int, string> v(3); assert(v.is_a<int>()); assert(!v.is_a<string>()); This can be done using the which() method, but its drawback is that I rely on the order of the types in the variant declaration rather on the type, which is really what I'm interested in. I can implement the variant_is_a<>() feature using a visitor such as: template <typename T> struct is_a_visitor : public boost::static_visitor<bool> { template <typename U> bool operator()(const U &) const { return false; } bool operator()(const T &) const { return true; } }; template <typename T, class Variant> bool variant_is_a(const Variant &v) { return v.apply_visitor(is_a_visitor<T>()); } but this way has a problem: calling variant_is_a<double>() on a variant of type variant<int, string> (no double for this variant) will simply return false, rather than just not compile, which is what I prefer. Making this not compile will require a new feature from variant: a boolean constant 'can_be'. With this, the variant_is_a() function could be written with additional line: BOOST_STATIC_ASSERT(Variant::can_be<T>::value); IMO, the is_a/can_be features are general and useful enough to be included in the library. Wouldn't you agree? Yuval

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RE: [Boost-users] Re: Bug in boost::lambda using operator <<?
by Richard_Cox＠Dell.com 05 Feb '05

05 Feb '05

On Friday, February 04, 2005 5:47 PM Kevin Wheatley wrote: > > Richard_Cox(a)Dell.com wrote: > > > > The program below outputs > > > > String: <First string> Second string> Fourth string> Fifth string> > > > > All but the first "<" is missing. Any ideas? > > std::for_each(coll.begin(), coll.end(), out << gt << _1 > << L"> "); > > > does this work? > > std::for_each(coll.begin(), coll.end(), out << var(gt) << _1 << L"> > "); > > not sure of the fix, but out << gt associates left to right and is > evaluated once and has the type of out, you want it lazy evaluated so > that the whole of the expression is considered as one... see the > delaying constants and variables section of the lambda documents. > > Kevin Of course, "obvious" now :-( out << gt would evaluate returning the wostream which the lambda expression created from the 2nd and 3rd <<'s then operates on. Many thanks. Richard All opinions are mine and do not represent in any way the position of Dell Corporation.

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implementing an iterator
by Chris Goller 04 Feb '05

04 Feb '05

I'm using iterator_facade to implement an iterator over file based data. So, my question is, since deference returns a reference to a value does that reference need to persist when the iterator is incremented or decremented? Because this is file based data I can't always keep a reference around because the data is stored on disk. Thanks, Chris

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boost::function as drop-in replacment for ordinary function pointers?
by Oliver Kowalke 04 Feb '05

04 Feb '05

Hi, is it possible to use boost::function as drop-in replacment for ordinary function pointers - or are there some other solutions? I can't get the code below to work. thx and best regards, Oliver typedef void (*FunctionPointer) ( int); void my_fun( int i) { std::cout << i << std::endl; } class MyFun { public: void operator()( int i) { std::cout << i << std::endl; } }; class Test { public: void f( FunctionPointer fp) { fp( 1); } }; void main() { Test tst; MyFun mf; boost::function< void(int) > f; f = boost::ref( mf); // tst.f( my_fun); // works tst.f( f); // ??? - doesn't compile } -- DSL Komplett von GMX +++ Superg�nstig und stressfrei einsteigen! AKTION "Kein Einrichtungspreis" nutzen: http://www.gmx.net/de/go/dsl

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Bug in boost::lambda using operator <<?
by Richard_Cox＠Dell.com 04 Feb '05

04 Feb '05

The program below outputs String: <First string> Second string> Fourth string> Fifth string> All but the first "<" is missing. Any ideas? (On vc++7.1 using Boost 1.32.0.) Richard All opinions are mine and do not represent in any way the position of Dell Corporation. #include <ostream> #include <iostream> #include <string> #include <vector> #include <algorithm> #include <boost/lambda/lambda.hpp> using std::wstring; using std::wcout; using std::endl; using boost::lambda::_1; typedef std::vector<wstring> StringCollection; wstring gt(L"<"); std::wostream& operator << (std::wostream& out, StringCollection const& coll) { std::for_each(coll.begin(), coll.end(), out << gt << _1 << L"> "); return out; } int main(int, char*[]) { StringCollection s; s.push_back(L"First string"); s.push_back(L"Second string"); s.push_back(L"Fourth string"); s.push_back(L"Fifth string"); wcout << L"String: " << s << endl; return 0; }

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