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

[variant][any] template parameterized variant
by alfC 09 Oct '10

09 Oct '10

Hi, I need a variant type object that can hold any type characterized by a template. For example Boost.Units have a family of types parameterized by "System". quantity< unit<dimension, System>, double> suppose dimension is fixed, e.g. typedef boost::units::length dimension is it possible to define a variant over that family of types? I could create a make_variant_over< list of all types > but that can be that list will be fixed and each time I defined a new System the list will have to grow. to simplify the question: template<class T> class dummy{ ... }; variant< "dummy<T>" > v; //for all T If it simplifies things, suppose that all dummy<T> have the same sizeof and that all are convertible to each other. Or should I be using an extension of boost::any with some adhoc restriction over the possible types on construction? Thank you, Alfredo

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[fusion] .at<N>() template member in containers?
by alfC 09 Oct '10

09 Oct '10

Hi, Excuse my simple minded questions. Sometimes by asking this question (often with negative answer) I understand more on the design of the Boost libraries. Besides possible redundancy, why is that the fusion containers, for example fusion::vector, doesn't have a template member function to extract elements? fusion::vector<double, int, std::string> stuff(1.2, 3, "hola"); stuff.at<2>(); //returns "hola", just like at_c<2>(stuff); Wouldn't it be more consistent with std::vector v, v[2] or v.at(2); By the way, does anybody know where the name given "at_c" (I mean the '_c') comes from? Thank you, Alfredo

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boost/preprocessor checking if argument is a constant
by Z S 09 Oct '10

09 Oct '10

All the BOOST_PP functions only work on integer constants. I want to write macros, where the same interface can be used for both constants and variables, and only call the BOOST_PP if the argument is a constant, and use runtime code if it is a variable. For example, #define TWICE(n) BOOST_PP_IF( _IS_CONSTANT(n), \ BOOST_PP_MUL(n,2), \ ( (n) * 2) ) For more details, you can also see the original question here : http://stackoverflow.com/questions/3884489/mixing-variables-and-integer-con… Is there a way to do so? The C preprocessor knows whether something is a constant, so we should be able to do this somehow. Or should I suggest this as a feature request for the Boost Preprocessor library? Thanks!

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Re: [Boost-users] Boost Logos: proposed high constrast logo
by Zoltan Juhasz 08 Oct '10

08 Oct '10

Follow up on the original topic: I've uploaded a high-contrast version of the Boost Logo, and moved all other logo related resources to the follow Google Docs folder: https://docs.google.com/leaf?id=0B_WA6oW88X1UZWZiNzUwYzctYzg1NS00ZmY5LTllMD… On the logo discussion: Various explanation could be made for the logo. For some these are molecular structures; for others this is a small matrix of hexagonal cells from a beehive; some may claim these are interconnected - in some places overlapping - software components etc. Probably all of these seem reasonable, maybe non of these for someone. My point is that one could come up with any justification for the hexagons, but it will not change others mindset on it. On the other hand... ... this is an abstract logo, which is fairly simple (well at least the stylized form), it does not bring any cultural or any specific technology connotations, and most importantly provides / provided a "face" for Boost in the last 4 (or 5?) years. This is a strong connection in public mind between the Boost community and the logo; where the previous one defines the later - which (the community, and the Boost project) has excellent reputation, which made the logo highly recognizable (like any famous company brand). The point is, it is not the logo which defines Boost, but the other way around. Ofc. if the logo was something like this: http://preview.tinyurl.com/2wcg757 that would be arguably a big deflection compared to the spirit of Boost, but I do not think this applies to the current case (chemical analogy). The other important point is that most of the developers that used Boost in the previous years, already made the connection between the logo and the Boost Libraries; making a radical change might be a bad idea, unless there is a really strong reason to do that (for example Boost ceases using C++, and focusing on Objective C from now), otherwise keeping the continuity is important. I hope the high contrast version of the logo is usable, let me know if you need further help with it. I also hope that I was able to give you some background on the abstract hexagons. Regards, Zoltan Juhasz

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[proto] baby steps learning with proto, proxy object
by alfC 08 Oct '10

08 Oct '10

Hi, This can be an exercise for definining the scope of Boost.Proto for little things. I have a histogram class that internally looks like this class histogram{ ... bool operator()(double const& x){return impl.increment(x);} bool operator()(double const& x, double const& weight){return impl.accumulate(x, weight);} }; histogram h( .. bin spec .. ); double x = ... ; so to add a count to the bin of x, I call h(x); to add a count with weigh w to bin x, I call h(x,w); so far so good. Now suppose I want to "improve" the syntax. The desired syntax would be: h[x]++; h[x]+=w; I don't want to expose the internal representation of the bins, so I can't return a reference to something from h[x]. So I guess we can create a proxy of the expression h[x] , "subindex of historgram with double". The proxy can be used with the syntax to call either accumulate or increment depending on the application of += or + + to the proxy. The naive implementation is this: class histogram{ ... private: struct proxy_histogram_subscript{ histogram& self; double const& x; proxy_histogram_subscript(histogram& self, double const& x) : self(self), x(x){} proxy_histogram_subscript const& operator++() const{self.increment(x); return *this;} bool operator++(int) const{return self.increment(x);} bool operator+=(double const& weight) const{return self.accumulate(x, weight);} }; public: proxy_histogram_subscript operator[](double const& x){ return proxy_histogram_subscript(*this, x); } }; which allows the desired syntax. The question is, can Boost.Proto do better? What I don't understand is how proto can make such a mini language *inside* the class. Hopefully without adding to much lines of code. I can see that one could create a histogram terminal, but that will be public (e.g. from the main program) and that will allow to create all sorts of expression involving brackets of anything. Thank you, Alfredo

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How to abort boost test execution on the failure of any BOOST_TEST_CASE
by Gaurav N Shah 08 Oct '10

08 Oct '10

Hi, I have sample code like this: void test1() { BOOST_REQUIRE(2 ==1); } void test2() { BOOST_CHECK(1 !=1); } boost::unit_test::test_suite* ts1 = BOOST_TEST_SUITE( "test_suite1" ); ts1->add(BOOST_TEST_CASE(&test1)); ts1->add(BOOST_TEST_CASE(&test2)); ::boost::framework::master_test_suite().add(ts1); In this case I do not want test2 function to be executed it test1 fails. How is it possible?? (I can not merge code in test1 and test2 into single function) Thank You, Gaurav This communication is for informational purposes only. It is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. All market prices, data and other information are not warranted as to completeness or accuracy and are subject to change without notice. Any comments or statements made herein do not necessarily reflect those of JPMorgan Chase & Co., its subsidiaries and affiliates. This transmission may contain information that is privileged, confidential, legally privileged, and/or exempt from disclosure under applicable law. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. Although this transmission and any attachments are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by JPMorgan Chase & Co., its subsidiaries and affiliates, as applicable, for any loss or damage arising in any way from its use. If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. Thank you. Please refer to http://www.jpmorgan.com/pages/disclosures for disclosures relating to European legal entities.

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Program Options.. Specifying "-e" as an option value.....
by david.weber＠l-3com.com 08 Oct '10

08 Oct '10

I have an application, which spawns off other applications. As input, it takes in environment variables and arguments to pass to the resultant application. For instance: mutate -E "env_var1=val" -a "." ls This will run: ls . and the environment will only have "env_var1" equal to "val" So. Something funny comes along when I try to pass "-e" as an argument. So, in the above would be: mutate -a "-e" -a "foo" xterm The program options parser attempts to parse the "-e", and says "I don't know what it is". Any thoughts on having it skip that option? Code Snippits: po::options_description visible("Program options. Usage %1%"); visible.add_options() ("env,E", po::value<string_vector_t>(), "Specify an environment variable to run the executable with. In the form of foo=bar") ("arg,a", po::value<string_vector_t>(), "Specify a command line argument to pass to the executable") ; // Set up some hidden options po::options_description hidden("Hidden options"); hidden.add_options() ("executable", po::value < std::string>(), "the executable to run") ; // Set up positional arguments. They are going to be execute po::positional_options_description pos; pos.add("executable", 1); // There can only be 1 item executed // Consolidate all the options into a single one po::options_description all_options("All Options"); all_options.add(visible); all_options.add(hidden); // Parse the command line options po::store(po::command_line_parser(argc, argv).options(all_options).positional(pos).run(), vm); po::notify(vm);

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[Boost.Log] How to link with on MSVC 2008?
by RUOFF, LARS (LARS)** CTR ** 08 Oct '10

08 Oct '10

Hello, i have found the following instructions to build Boost.Log: > Boost.Log can be compiled by: > > 1. Getting 1.42 source release > 2. Unpacking Boost.Log on top of it > 3. Following the usual procedure: > > .\bootstap.bat > .\bjam --with-log I did the above starting from a 1.44 source release. This worked out well. But when trying to use the library I get a lot of linker errors in my project: 1>Linking... 1>libboost_log-vc90-mt-gd-1_44.lib(text_file_backend.obj) : error LNK2019: unresolved external symbol "class boost::filesystem2::file_status [...] (Very long error messages containing decorated names. The above is just the start) Linker path settings should be correct, since the linker correctly finds libboost_log-vc90-mt-gd-1_44.lib. Also the project is using other Boost libraries (Asio, shared-ptr, bind, posix-time, etc) without problems. Anyone managed to compile and use Boost.Log on MSVC 2008 and can help? Thank you, Lars Ruoff

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[Math] Best Way to Produce Pi
by Hossein Haeri 08 Oct '10

08 Oct '10

Dear all, What's my best way to define a constant for Pi. I'm thinking of using the following <cmath> stuff: const double pi(4 * atan(1)); Does Boost provide a better solution? TIA, --Hossein

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[boost-users] [bind][function] - too many copies
by Lorimer, Stephen 08 Oct '10

08 Oct '10

For a given member function of the form void foo::f0(), passing this to boost bind results in the class instance being copied 7 times. Storing the result of bind in boost function incurs another 11 copies (code and results are here: http://boost.codepad.org/6jBmoKuj) Using tr1::bind and function has slightly better results, but still not ideal: Doing just tr1::bind results in the class instance being copied 4 times. Storing the result of bind in tr1 function incurs another 3 copies (code and results are here: http://boost.codepad.org/w1EV6JBY) Am I right in saying this is because boost::bind uses normal templates while tr1::bind uses variadic templates? Either way this is not very efficient. Is there a way to improve this? ---------------------------------------------------------------------- This message w/attachments (message) is intended solely for the use of the intended recipient(s) and may contain information that is privileged, confidential or proprietary. If you are not an intended recipient, please notify the sender, and then please delete and destroy all copies and attachments, and be advised that any review or dissemination of, or the taking of any action in reliance on, the information contained in or attached to this message is prohibited. Unless specifically indicated, this message is not an offer to sell or a solicitation of any investment products or other financial product or service, an official confirmation of any transaction, or an official statement of Sender. Subject to applicable law, Sender may intercept, monitor, review and retain e-communications (EC) traveling through its networks/systems and may produce any such EC to regulators, law enforcement, in litigation and as required by law. The laws of the country of each sender/recipient may impact the handling of EC, and EC may be archived, supervised and produced in countries other than the country in which you are located. This message cannot be guaranteed to be secure or free of errors or viruses. References to "Sender" are references to any subsidiary of Bank of America Corporation. Securities and Insurance Products: * Are Not FDIC Insured * Are Not Bank Guaranteed * May Lose Value * Are Not a Bank Deposit * Are Not a Condition to Any Banking Service or Activity * Are Not Insured by Any Federal Government Agency. Attachments that are part of this EC may have additional important disclosures and disclaimers, which you should read. This message is subject to terms available at the following link: http://www.bankofamerica.com/emaildisclaimer. By messaging with Sender you consent to the foregoing.

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Boost Logos: proposed high constrast logo
by Alfredo Correa 08 Oct '10

08 Oct '10

Hi all, In my opinion there should be a high contrast version of the Boost logo . (by that I mean either black and white or high contrast with very mild gradients on white background). Particularly I am talking about the three hexagons icon. As an example, the first attachment here has the official logo in SVG format. Because of the background gradient and the gradient fill of the hexagon it is not *obvious* how to convert this to high contrast. What should be replaced by black (or solid blue)? the hexagon filling? the hexagon borders? the background? A possible high contrast logo is attached in the second file. By no means official or the best option, it is just an possibility, maybe the simplest one. *Just an example*. Note that even the darkest blue used in the gradient of the official logo is not enough to contrast with white, so I used a darker blue. The reason I think a high contrast logo is the following: If you want to have a document printing quality (or high quality PDF) you need a vector format. If the printing or visualization is done in black and white, the logo should have high contrast otherwise the appearance will be very device dependent. While everyone should take care in printing in good devices having a logo that is barely visible in black/white/grey printing in some devices is not acceptable. As a test for what makes a high contrast logo a good one, just try printing and small version (one centimeter square) of the logo in a black and white laser printer with random text around it and you will see the problem with the low contrast original logo. It will appear like a grey blob at best. Please this thread is not about a new logo design just an adaptation of the existing one. This thread is not be related with the "Powered by" logo discussion Alfredo PS: the attachments are Inkscape SVG.

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[statechart] Unhandled events
by Oleg Smolsky 07 Oct '10

07 Oct '10

Hey there, I've been using SC for a while and something has been bugging me - given a state machine with: OuterSt, OneSt and TwoSt as well as OneEv and TwoEv that are handled by OneSt and TwoSt respectively, it is possible to send a wrong event to either of the last two states. Such an "unhandled" event will be forwarded to OuterSt and then quietly eaten. My question is as follows - is it possible to define some kind of "catch all" handler in the OuterSt? I have already fixed a tricky bug in my code where a submitted event was lost, and wonder if there is a simple way to handle these situations? I can certainly add a custom_reaction<>(X) for each possible event to the OuterSt and catch issues that way, but that's far from ideal. Any suggestions would be appreciated. P.S. perhaps a compromise solution would be to add something like this to OuterSt: sc::bug<OneEv> sc::bug<TwoEv> but that would effectively limit handling to issuing an assert(false)... Thanks, Oleg.

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[boost-spirit qi] internal copies
by Ovanes Markarian 07 Oct '10

07 Oct '10

Hello *, I think this is more the question to spirit devlopers. I would like to know how spirit internally maintains the parsed data? Here is an example of what I mean. I have to parse some byte sequence represented as hex pairs: 00 ce ab 00 de ad be ef ... If I use the parser like this: boost::spirit::qi::uint_parser<unsigned char, 16, 2,2> hex_byte; std::string str("..."); std::vector<byte_t> vec; iter_type curr=str.begin(), end=str.end(); bool r=phrase_parse(curr, end, +hex_byte, space, vec); Is vec going to be copied somewhere inside of qi? Or are the bytes directly appended to the vec? I would like to reserver some space for the maximum possible input and avoid additional internal copies inside of qi... How does the behaviour changes std::vector<byte_t> is part of the fusion::map like fusion::map < fusion::pair<tag1, string> , fusion::pair<tag2, string> ... , fusion::pair<tagN, std::vector<byte_t> > > data_item; Are the fields of the map used directly while parsing, or are there some temporaries, which will be first created (somewhere inside qi core) and filled with data and afterwards assigned to the corresponding map field? Many thanks for the gread lib! Ovanes

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[boost::math]binomial_coefficient compile error
by Suresh Kumar 07 Oct '10

07 Oct '10

Hi this code gives a compile error. #include <iostream> #include <boost/math/special_functions/binomial.hpp> using namespace std; int main(){ cout << boost::math::binomial_coefficient(10,1) << endl; } binom.cpp:8: error: no matching function for call to ‘binomial_coefficient(int, int)’ what is that I am missing? thanks suresh -- R Suresh Kumar, http://www.ee.ucr.edu/~sramachandranna Sarve bhavantu sukinaha (May everyone be happy) Sarve santu niramiyaha (May everyone be without affliction) Sarve bhadrani pashyantu (May everyone see only goodness) Ma kashchit dukha bhak bhavet (Let none be the victim of suffering)

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[Python] Unable to use static library of boost.python due to undefined symbols
by Philipp Münzel 06 Oct '10

06 Oct '10

Hi folks, I'm trying to build a python extension with statically linked libboost_python on Linux. I built boost_python with ./bjam -q --layout=system --with-python toolset=gcc variant=release link=static threading=multi runtime-link=static which results in a 700kb libboost_python.a Then I try to build the hello world example located at /libs/python/example/tutorial but I fail, because their remain undefined symbols, despite the fact I did define BOOST_PYTHON_STATIC_LIB. Heres what I did: $ cat hello.cpp // Copyright Joel de Guzman 2002-2004. Distributed under 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) // Hello World Example from the tutorial // [Joel de Guzman 10/9/2002] #include <boost/python/module.hpp> #include <boost/python/def.hpp> char const* greet() { return "hello, world"; } BOOST_PYTHON_MODULE(hello_ext) { using namespace boost::python; def("greet", greet); } $ g++ -I/usr/local/include -I/usr/include/python -DBOOST_PYTHON_STATIC_LIB -fpic -c -o hello.o hello.cpp $ g++ -shared -Wl,-soname,"libhello.so" -L/usr/local/lib -lboost_python -fpic -o libhello.so hello.o $ nm -u libhello.so U PyString_Type w _Jv_RegisterClasses U _Py_NoneStruct U _Unwind_Resume@@GCC_3.0 U _ZN5boost6python6detail11init_moduleEPKcPFvvE U _ZN5boost6python6detail12gcc_demangleEPKc U _ZN5boost6python6detail17scope_setattr_docEPKcRKNS0_3api6objectES3_ U _ZN5boost6python7objects15function_objectERKNS1_11py_functionE U _ZN5boost6python7objects21py_function_impl_baseD2Ev U _ZN5boost6python9converter19do_return_to_pythonEPKc U _ZN5boost6python9converter8registry5queryENS0_9type_infoE U _ZNK5boost6python7objects21py_function_impl_base9max_arityEv U _ZNK5boost6python9converter12registration25expected_from_python_typeEv U _ZTIN5boost6python7objects21py_function_impl_baseE U _ZTIPKc@@CXXABI_1.3 U _ZTIc@@CXXABI_1.3 U _ZTVN10__cxxabiv120__si_class_type_infoE@@CXXABI_1.3 U _ZTVN5boost6python7objects21py_function_impl_baseE U _ZdlPv@@GLIBCXX_3.4 U _Znwm@@GLIBCXX_3.4 U __cxa_atexit@@GLIBC_2.2.5 w __cxa_finalize@@GLIBC_2.2.5 U __cxa_guard_abort@@CXXABI_1.3 U __cxa_guard_acquire@@CXXABI_1.3 U __cxa_guard_release@@CXXABI_1.3 w __gmon_start__ U __gxx_personality_v0@@CXXABI_1.3 $ python >>> import libhello Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: ./libhello.so: undefined symbol: _ZNK5boost6python7objects21py_function_impl_base9max_arityEv The example works marvellous when using the shared lib of boost_python, but it has to be a static build for me. I found a mailing list entry from 2002 mentioning the static build of boost.python was broken, but that is for sure fixed by now, isn't it? Regards, Philipp

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[Fusion] How to join more than two sequences
by Clinton Mead 06 Oct '10

06 Oct '10

Hi All I've noticed the function "join" in the boost fusion library. However, it only joins two sequences. Was wondering whether there is (or can be easily made) a function that joins any number of sequences. For example: new_join(make_vector(1,2,3), make_vector(4,5), make_vector(6)) -> is the sequence 1,2,3,4,5,6 AND/OR (pass parameters in a sequence) new_join(make_vector(make_ vector(1,2,3), make_vector(4,5), make_vector(6))) -> is the sequence 1,2,3,4,5,6 I'd prefer both the first and second versions, but even one version would be ok. Thanks, Clinton

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[filesystem] V3 path::replace_extension() spans path components
by Timothy Madden 06 Oct '10

06 Oct '10

Hello It appears that in boost 1.44.0 filesystem V3 path("\Cristina.ADI\Local Settings").replace_extension(".png") just returns "\Cristina.png" instead of "\Cristina.ADI\Local Settings.png" Could this be fixed ? Thank you, Timothy Madden

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[proto]Compile issue on Sun Solaris 10, Sun Studio 12.2
by Sascha Ochsenknecht 06 Oct '10

06 Oct '10

Hello, I got an error from the Sun Studio 12.2 (CC 5.11) when trying to compile my sources. The error comes out of the Boost.Proto library (actually I'm doing something with Boost.Spirit and Boost.Spirit is using Boost.Proto ..., but I don't think that the problem is in the client code, it seems to come from the buggy compiler). I'm using Boost 1.43. This is what I got from the compiler: "...include/boost/proto/detail/decltype.hpp", line 343: Error: Partial specialization parameter V is not used in the arguments. "...include/boost/proto/transform/arg.hpp", line 287: Error: Partial specialization for boost::proto::_byval::result has identical arguments. "...include/boost/proto/extends.hpp", line 600: Error: type is not a member of boost::result_of<boost::proto::domainns_::default_domain>. "...include/boost/spirit/home/support/terminal.hpp", line 237: Where: While specializing "boost::proto::exprns_::extends<boost::proto::exprns_::expr<boost::proto::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::bin>, 0>, boost::spirit::terminal<boost::spirit::tag::bin>, boost::proto::domainns_::default_domain, 0>". (the following is talking about "include/boost/proto/detail/decltype.hpp", line 343) With g++ this code compiles without any problems and runs as expected. Searching around the internet, I got the following bug entry of the Sun Studio compiler: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6926895 It looks like a similar problem. The bug entry contains a small example which reproduces the compile error: template <typename T> struct test { T t; }; template <typename T, typename X> struct test<X T::*> { X T::* x; }; template <typename T> struct test2 {}; template <typename T, typename X> struct test2< test<X T::*> > { test<X T::*> xt; }; int main() { test<int> a; a.t = 1; int test<int>::* s = &test<int>::t; test<int test<int>::*> a2; a2.x = s; test2<test<int test<int>::* > > a3; a3.xt = a2; return a.*a3.xt.x; } $ CC example.C "example.C", line 4: Error: Partial specialization parameter T is not used in the arguments. The bug entry also provides a workaround which seems to work. Replace the template types with the following: template <typename T> struct helper { }; template <typename T> struct test2 : public test2< helper<T> > { }; template <typename T> struct test2<helper< T> > { } ; template <typename T, typename X > struct test2< helper<test<X T::* > > {test<X T::*> xt; }; I would like to try a similar workaround adapted to the Boost.Proto source code. I tried several things but since I'm not fully aware what is going on in the proto sources and what is the exact reason the compiler fails, I couldn't make it work so far. Does anybody had a similar problem or does anybody know how to adapt the Boost.Proto source to make the Sun compiler happy? BTW: For me it would be ok for now to patch my local Boost source files. Here is the snippet from proto/detail/decltype.hpp: //////////////////////////////////////////////////////////////////////////////////////////// // result_of_ is a wrapper around boost::result_of that also handles "invocations" of // member object pointers. template<typename T, typename Void = void> struct result_of_ : boost::result_of<T> {}; // THE FOLLOWING IS TROUBLE MAKER FOR THE SUN COMPILER -> template<typename T, typename U, typename V> struct result_of_<T U::*(V), typename enable_if_c<is_member_object_pointer<T U::*>::value>::type> { BOOST_STATIC_CONSTANT(bool, is_V_a_smart_ptr = 2 == sizeof(test_V_is_a_U<U>(&lvalue(make<V>())))); BOOST_STATIC_CONSTANT(bool, is_ptr_to_const = 2 == sizeof(test_ptr_to_const(BOOST_PROTO_GET_POINTER(U, make<V>())))); // If V is not a U, then it is a (smart) pointer and we can always return an lvalue. // Otherwise, we can only return an lvalue if we are given one. typedef typename mpl::eval_if_c< (is_V_a_smart_ptr || is_reference<V>::value) , mpl::eval_if_c< is_ptr_to_const , add_reference<typename add_const<T>::type> , add_reference<T> > , mpl::identity<T> >::type type; }; Thanks in advance, Sascha

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boost 1.44.0 undefined reference to boost::filesystem2::no_check
by Asif Fayyaz 06 Oct '10

06 Oct '10

Hi, I am compiling a very simple application using boost filesystem. However it is giving following error message: "undefined reference to `boost::filesystem2::no_check(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'" Here is the simple application source: --------------------------------Sample application source: #include <stdio.h> #include <boost/filesystem.hpp> int main() { std::string m_FileName(boost::filesystem::path("testfile1.txt", boost::filesystem::no_check).native_file_string()); printf("Testboost.....%s\n", m_FileName.c_str()); return 0; } -------------------------------- More Details: Libraries being used: libboost_filesystem-gcc41-mt-1_44.a libboost_system-gcc41-mt-1_44.a Boost version: 1.44.0 Boost was build using command: bjam --build-type=complete --layout=versioned Operating System: Linux CentOS5.2 Any help in this regard will be appreciated. Asif

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Re: [Boost-users] Users! Who'd like to wave goodbye to #ifdef
by Paul Kerchen 06 Oct '10

06 Oct '10

+1 for removing VC6 support. Paul Kerchen

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Re: [Boost-users] Problems with boost 1.44.0 and MSVC: deque problem seems solved, but the boost::ctor problem remains
by Yana A Kireyonok (aka Iron Bug) 06 Oct '10

06 Oct '10

> Date: Tue, 5 Oct 2010 11:37:35 +0200 > From: Igor R <boost.lists(a)gmail.com> > 2010/10/5 Yana A Kireyonok (aka Iron Bug) <death.iron.bug(a)gmail.com>: >> Greetings, ppl. >> I've got strange problems with the latest stable boost (1.44.0) and >> MSVS studios 2005 and 2010. >> ... > According to your description, it seems that the issue you encountered > is only a symptom of some memory-management issue in your code >..... Well, it could happen if I wasn't a professional programmer (over 15 years of real time systems hardware and software programming). It's not a typical beginners mistake, for sure. I wouldn't bother ppl in here if I hadn't checked all possible variants and wasn't sure it was really something out of order. > Date: Tue, 5 Oct 2010 12:38:02 +0000 > From: David Ward <davidjward30(a)hotmail.com> > >> Greetings, ppl. >> I've got strange problems with the latest stable boost (1.44.0) and >> MSVS studios 2005 and 2010. >> > Hi, > You might want to check out this known bug with std::deque in MSVC. It's due > to be fixed in VC11: > https://connect.microsoft.com/VisualStudio/feedback/details/533131/bug-in-s… > Regards, > David. Yes, this is very possible! I performed some more experiments, encountering the bug issue you mentioned and in my case it seems being the pop_front method that ruins the iterators, despite of using interlocking mechanism. Perhaps, it's the matter of timings: that's why it doesn't trigger when I use other locking methods. But I should uproot using deques in my code, anyway. It may show up again on faster or slower machines. Well, I will be aware of danger of using deques in MSVS. Never liked MS, to say the truth... :) But have to deal with it sometimes. Still, remains the question what to do with constructor of boost::thread in MSVS 2010. It fails with access violation, without any specific conditions, in simple plain piece of code.

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[Fusion] fusion vector transformation into another fusion vector transformation.
by alfC 05 Oct '10

05 Oct '10

I have class that is parameterized by several type (Boost::Unit units type). template<class U1, class U2, ... > class A{ A(quantity<U1> q1, quantity<U2> q2, ... ){} }; since the number of arguments is arbitrary I though it would be a good idea to use either MPL sequence and Tuples. Or better yet a fusion::vector. so the class will be parametrized by a fusion::vector or unit types. template<class FusionOfUnits> //or class MPLofUnits class A{ A(FusionOfQuantities fq){} //or TupleOfUnits }; The questions is: ¿what is the best way to transform a fusion::vector<unit1, unit2, unit3, ..., unitN > into a fusion::vector<quantity<unit1>, quantity<unit2>, quantity<unit3>, ..., quantity<unitN> > whete the N is (compile-time) arbitrary, i.e. the lenght of the fist fusion::vector is arbitrary (If you are not familiar with Boost.Units, unitN is just a type and quantity is a template type.) Thank you, Alfredo

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timezone database discrepancy
by archie14 05 Oct '10

05 Oct '10

I am calculating start/end time of the daylight savings time using tz_database and default timezone database file "date_time_zonespec.csv" that comes with boost 1_44. I found discrepancy between results of the calculation for "America/Chicago" region and published data. for years 2010-2007 the results match. However, for the 2006 calendar year, published results from several sources are: Start: April 2 End: October 29 and calculated results are: Start: March 12 End November 5 I will appreciate any advise/comments on how to deal with this issue.

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Re: [Boost-users] [proto] need explanation in implementing distributive law
by Mauro Bianco 05 Oct '10

05 Oct '10

Hi all, It is probably already been discovered by everyone at this point, but the code proposed by Andrew does not to work properly to apply distributivity more than once in an expression [works for a*(b+c) but not for a*(b+c*(d+c)) ] Here a modified version that seems to work recursively. How does it look? struct distr : proto::or_< proto::when< proto::multiplies< proto::_, proto::plus< proto::_, proto::_ > >, proto::call<distr( // THIS IS TO RECURSE proto::_make_plus( proto::_make_multiplies( proto::_left, proto::_left( proto::_right ) ), proto::_make_multiplies( proto::_left, proto::_right( proto::_right ) ) ) ) > >, proto::otherwise<proto::nary_expr<proto::_, proto::vararg<distr> > > > {}; Regards, Mauro. On 22.03.2010 22:11, Andrew Durward wrote: > As a follow-up, the attached code seems to compile and yield the expected > result. > > andrew > > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Serialize a class, call new() in constructor
by Michael Reichlin 05 Oct '10

05 Oct '10

Hi everybody, actually i have a big problem with serializing some of my classes. The problem is, that classA class calls new of classB in constructor and after that the load_construct_data is called and also calls a new of classB. So I have two objects of classB. Here is my code: classA.h: class CClassA { template<class Archive> friend void serialize(Archive &ar, CClassA &cCClassA, const unsigned int version); template<class Archive> friend void save_construct_data(Archive &ar, const CClassA *cCClassA, const unsigned int version); template<class Archive> friend void load_construct_data(Archive &ar, CClassA *cCClassA, const unsigned int version); // *** Aufzählungen **************************************************************************** public: CClassB* pClassB; // *** Methoden ******************************************************************************** private: protected: int iTest; public: CClassA(int iTest); // Konstruktor virtual ~CClassA(); // Destruktor // Get/Set-Methoden }; classA.cpp: CClassA::CClassA(int iTest) :iTest(iTest) { pClassB = new CClassB(iTest); } classB.h: class CClassB { template<class Archive> friend void serialize(Archive &ar, CClassB &cCClassB, const unsigned int version); template<class Archive> friend void save_construct_data(Archive &ar, const CClassB *cCClassB, const unsigned int version); template<class Archive> friend void load_construct_data(Archive &ar, CClassB *cCClassB, const unsigned int version); // *** Aufzählungen **************************************************************************** public: // *** Datenmember ***************************************************************************** private: protected: public: // *** Methoden ******************************************************************************** private: protected: int iTestInt; public: CClassB(int iTest); // Konstruktor virtual ~CClassB(); // Destruktor // Get/Set-Methoden static unsigned int count; }; serialize.h template<class Archive> void serialize(Archive &ar, CClassA &cCClassA, const unsigned int version) { ar & boost::serialization::make_nvp("ClassB", cCClassA.pClassB ); } template<class Archive> void save_construct_data(Archive &ar, const CClassA *cCClassA, const unsigned int version) { ar << boost::serialization::make_nvp("Test", cCClassA->iTest); } template<class Archive> void load_construct_data(Archive &ar, CClassA *cCClassA, const unsigned int version) { int iTest; ar >> boost::serialization::make_nvp("Test", iTest); ::new(cCClassA) CClassA(iTest); } template<class Archive> void serialize(Archive &ar, CClassB &cCClassB, const unsigned int version) { } template<class Archive> void save_construct_data(Archive &ar, const CClassB *cCClassB, const unsigned int version) { ar << boost::serialization::make_nvp("Test", cCClassB->iTestInt); } template<class Archive> void load_construct_data(Archive &ar, CClassB *cCClassB, const unsigned int version) { int iTest; ar >> boost::serialization::make_nvp("Test", iTest); ::new(cCClassB) CClassB(iTest); } Now I just want that only one ClassB will be created. How can I recognize, that ClassB is already generate through cons tructor classA. I just want to serialize the members of classB. Is there a way to solve my problem?? Best regards Michael

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