October 2007 - Boost-users - lists.preview.boost.org

Pattern-matching by metaprogramming - possible?
by Ovanes Markarian 18 Oct '07

18 Oct '07

I don't think that meta-programming will help check you the values. This can only be the case if the values are available (as const with external linkage) at compile time. If you need the checking pattern to be generated during the compilation than take a look at boost::xpressive. With Kind Regards, Ovanes On 10/18/07, Zeljko Vrba <zvrba(a)ifi.uio.no> wrote: > > On Thu, Oct 18, 2007 at 09:04:39AM +0200, Ovanes Markarian wrote: > > > > Hello Zeljko, > > > > may be another approach? Why not using a template method and static > concepts > > inside a function, which ensure that a parameter is of correct type? > > > Hmm, I didn't quite get you. But I want to match both on *type* and > *value* > as shown in this rule: > > > > > > | (Insn "addq", Reg "%rsp") -> (* do something *) > > > > The type here is (Insn, Reg) [particular types of larger variants]; > each component is also matched on the particular value ("addq" and > "%rsp" strings). > > > > > > | (_, Imm x) -> (* any 1st item; the 2nd must be Imm type, and > > > > the x variable is bound to the value carried by the > 2nd > > > > The type here is doesn't matter and (Imm x) - this is a match only > on type where the variable x gets bound to the value carried by > the variant type. > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

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Pattern-matching by metaprogramming - possible?
by Zeljko Vrba 18 Oct '07

18 Oct '07

A short introduction: the ML language has a variant data type, tuples, and pattern matching construct. For example type operand = Imm of int | Reg of string type instruction = Insn of string | Pseudo of string Now, we can create tuples, e.g. (Insn "push", Reg "%rbp") is of type operand * instruction (a tuple of two typed elements). In function definitions, it is possible to do pattern matching as (it could be written slightly better in ML, but I want to show the match syntactic construct): let f x = match x with | (Insn "addq", Reg "%rsp") -> (* do something *) | (_, Imm x) -> (* any 1st item; the 2nd must be Imm type, and the x variable is bound to the value carried by the 2nd item *) | (_, Reg "%rsp") -> (* any value for 1st item _except_ Insn "addq" which has already been handled in the first alternative - alternatives are matched in order and first matching is taken *) | _ -> (* default case for anything else *) This is only a simplified example; but even this example would be much more ugly if rewritten with if/else statements, even if tuple tiers were used. Boost provides both the safe variant type and the tuple type. Would it be possible to construct pattern matching with syntax similar to the above in C++ ? [Yes, there are also other problems - incomplete matches: ML just throws an exception in that case; or redundant cases - nothing happens.]

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Quasi-random
by Joel C. Salomon 17 Oct '07

17 Oct '07

I've found some mention of this in the archives, but it seems it's never been done. How much work would it be to add the quasi-random sequence generators (faure, halton, hammersley, sobol, &c.) from the code at <http://people.scs.fsu.edu/~burkardt/cpp_src/cpp_src.html>? --Joel

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Problem lboost_filesystem-mgw-mt-s-l_33_l
by question boost 17 Oct '07

17 Oct '07

Hi , compiling a project under Code Blocks I get the following message: ld.exe:cannot find -lboost_filesystem-mgw-mt-s-l_33_l I go there http://www.boost.org/doc/html/jam/building.html I do:C:\Documents and Settings\src\boost\tools\jam\src>build mingw --debug (like explained) A new folder named bin.ntx86.debug is added after I go there http://www.boost.org/doc/html/bbv2/installation.html : 1:(done) 2:I do:C:\Documents and Settings\src\boost\tools\build\v2> bjam --version 3:I open the user-config.jam file (like explained) and I modify the file, the modification is the following: import toolset : using ; # GCC configuration # Configure gcc (default version) using gcc : : "C:\mingw\bin\g++" ; 4:I copy bjam.exe from C:\Documents and Settings\src\boost\tools\build\v2 to C:\Documents and Settings\src\boost\tools\build\v2\example\hello and I run bjam (like explained): C:\Documents and Settings\src\boost\tools\build\v2\example\hello>bjam I get the following message: "C:mingwbing++ n'est pas reconnu en tant que commande interne ou externe, un programme executable ou un fichier de commandes .." ..... "...failled gcc.compile.c++ bin\gcc\debug\hello.o... ...skipped <pbin\gcc\debug>hello.exe for lack of<pbin\gcc\debug>hello.o... ...failed updating one target.. ...skipped one target..." Where is my error (4)? Thanks, David _________________________________________________________________ Votez pour vos séries TV préférées et tentez de gagner un voyage à Hawaï ! http://messengerawards.divertissements.fr.msn.com/

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[ref] tying references between objects
by Robbie Morrison 17 Oct '07

17 Oct '07

Hi all The following kind of code is probably quite common. It involves: * using individual Register objects containing construction parameters to help factory-create new Entity objects * and, in the process, "tying" key object state variables so that each associated Registry object can watch these And yes, I know this breaks encapsulation! I chose C++ references and my code seems quite complicated for what should be a relatively straightforward task. Pointers were rejected because the dereferencing syntax can lead to really obscure numerical expressions (particularly for non-C/C++ programmers). However, boost::ref() seemed to offer a simpler solution and I experimented with this for quite some time to no avail. I also considered using a boost::ptr_vector and 1-tuples. In addition, adding cout statements to ctors and dtors led to more activity than I would have expected. Moreover, there were more dtor calls than ctor calls. Any comments or suggestions gratefully received! Also an explanation of the differences between a "type conversion" operator and an "address-of" operator. Is this simply related to role or is there a distinction? More information follows the program listing. many thanks in advance Robbie --- Robbie Morrison PhD student -- policy-oriented energy system simulation Institute for Energy Engineering (IET) Technical University of Berlin (TU-Berlin), Germany [from IMAP client] // --------------------------------------------------------- // Copyright: (c) 2007 Robbie Morrison. All rights reserved. // License: Unrestricted reuse in any form, for any purpose. // Version: $Id: frag-xeona-registers-9.cc,v 1.3 2007/10/17 15:23:43 robbie Exp $ // Tested using g++ 4.1.2 (-Wall -Weffc++ -pedantic), boost // 1.34.1 (source build), and valgrind (memory checker) on // Ubuntu 6.10 (7.04 is current) using Linux 2.6.17-12-generic. #include <iostream> // standard io #include <string> // C++ strings #include <vector> // STL sequence container #include <iomanip> // setw() and family #include <tr1/memory> // TR1 smart pointers using std::tr1::shared_ptr; // for convenience // --------------------------------------------------------- template <typename T> class Value // just for type conversion operator T&() { public: explicit Value(T v) : _value(new T(v)) { } operator T&() { return *_value; } // return aliasable value private: shared_ptr<T> _value; // pointer usage is essential }; // --------------------------------------------------------- class Register // initializes and watches selected { // .. Entity variables public: explicit Register() : _vec() { } // explicit for testing template <typename T> // would normally support int,double,bool Value<T> tieRef(const std::string& tag) // would normally search on tag! { T temp = 0.45; // would normally obtain value from user shared_ptr<Value<T> > val(new Value<T>(temp)); // actual object is shared _vec.push_back(val); // crude "last on" indexing for testing report(); return *_vec.back(); // given aforementioned "last on" indexing } void report() // just for doubles (could be templated) { double temp = *_vec.back(); // this line is interesting! std::cout << "Register : value : " << temp << std::endl; } private: std::vector<shared_ptr<Value<double> > > _vec; // data mirror }; // --------------------------------------------------------- class Entity // represents simulation 'things' { public: explicit // explicit for testing Entity(Register& r) : // pass-by-reference necessary _register(r), // for testing purposes _coeff(r.tieRef<double>("coeff")), // intuitive syntax _notInteresting() // rely on default construction { report(); } void modify(double d) { _coeff = d; // normal syntax (no pointer derefs) report(); // display this modification _register.report(); // confirm the modification propagated } void report() { std::cout << "Entity : value : " << _coeff << std::endl; } private: Register& _register; double& _coeff; // watched variable int _notInteresting; // ignored variable }; // --------------------------------------------------------- int main(int argc, char* argv[]) { std::cout << std::fixed << std::setprecision(2); std::cout << " creating a register" << std::endl; Register reg; std::cout << " creating an entity" << std::endl; Entity ent(reg); std::cout << " modifying the entity" << std::endl; ent.modify(0.01); ent.modify(2.0); } // ---- end-of-program ------------------------------------- // OUTPUT // creating a register // creating an entity // Register : value : 0.45 // Entity : value : 0.45 // modifying the entity // Entity : value : 0.01 // Register : value : 0.01 // Entity : value : 2.00 // Register : value : 2.00 // Development environment // // boost : 1.34.1 (via ./configure; make all; make install) // gcc : 4.1.2 20060928 (prerelease) (Ubuntu 4.1.1-13ubuntu5) // os : Ubuntu 6.10, Linux 2.6.17-12-generic (7.04 is current) // hardware : Toshiba Tecra A2 330 laptop (purchased 27-Aug-2004) // specs : 1.4GHz Intel Celeron M (32-bit) / 512MiB RAM / 40GB HDD // // Problem // // The problem involves sharing data between Entity objects, // used to represent various 'things' in my simulation -- // and Register objects ('register' in the sense of a book // recording important information), used to help construct // and then watch the state of Entity objects. A concrete // ObjectFactory object (not relevant to this discussion) // will be used to create the Entity objects (Alexandrescu // 2001 pp179-217). // // I would also like a relatively clear syntax for // programming the Entity's as there are lots of these and // they contain numerical expressions -- for instance, // dereferencing (smart) pointers would yield lines like: // // *_perf = 2.1 * local * *_coeff; // // Solution (provisional) // // The chosen strategy is to declare all to-be-observed // Entity object data members as references and then bind // these to the relevant Register object element upon // construction. // // An alternative approach could be to utilize the Memento // pattern (which relies on friendship) in conjunction with // the Iterator pattern (for traversing a population of // objects) (Gamma etal 1995 pp283-291 and pp257-271 // respectively). // // Design notes // // In relation to C++, a reference data member must be // initialized in the constructor's initializer list // (Lischner 2003 p36). And a reference may not be bound to // a class member (data member or member function) (p35). // // Class Value<T> is instead used to avoid an "invalid // initialization .. from a temporary" error when // initializing Entity::_coeff using the Register::tie<T> // member function. // // Class Value supplies a "type conversion operator" // (Lischner 2003 p112), in this case, Value::operator T&, // which binds to the non-const reference data member in // Entity. The code for Value derives from Lischner (2003 // p119 example 5-21). // // References // // Alexandrescu, Andrei. 2001. Modern C++ design : // generic programming and design patterns applied. // Addison-Wesley, Boston, USA. ISBN 0-201-70431-5. // // Gamma, Erich, Richard Helm, Ralph Johnson, and John // Vlissides. 1995. Design patterns : elements of // reusable object-oriented software. Addison-Wesley, // Boston, USA. ISBN 0-201-63361-2. // // Lischner, Ray. 2003. C++ in a nutshell : a language // and library reference, O'Reilly and Associates, // Sebastopol, California, USA. ISBN 0-596-00298-X.

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Re: [Boost-users] Boost Spirit and C++/CLI
by Hansi Hansi 17 Oct '07

17 Oct '07

When you use windows forms programs you can't use the standard main entry point with mixed unmanaged code. There is a bug in the initialization of the CRT in VS2005. It seems that the bug is not anymore in VS2008. Test it with the entry point '?mainCRTStartupStrArray@@$$FYMHP$01AP$AAVString@System@@@Z' Best regards Hansjörg _______________________________________________________________________ Jetzt neu! Schützen Sie Ihren PC mit McAfee und WEB.DE. 3 Monate kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?mc=022220

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boost::serialization(1.34.1) Can not link 64-bit example.
by Oleg Udovenko 16 Oct '07

16 Oct '07

Hi, Now I'm trying to use the "serialization" library on 64-bit(x64, Visual C++ 8.0). And faced some troubles with that. First I've converted a Visual Studio 2003 solution (vc7ide) to Visual Studio 2005, and compiled 64-bit static library release/debug. It passed the compilation with lots of warnings. But when I tried build a 64-bit example demo_xml_load.cpp I've got a lots of linker errors. - Is somebody tried the "serialization" library on 64-bit? Thanks, Oleg.

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What would happen if boost::shared_ptr is reset to an address in the stack
by Peng Yu 16 Oct '07

16 Oct '07

Hi, The following program runs well in my system. However, if I change 1 to 0, it will terminate at the line with "delete". Does this mean that boost::shared_ptr can tell if the pointer is from the stack or the heap and does different things based on where the pointer is from? Thanks, Peng #include <iostream> #include <boost/shared_ptr.hpp> int main() { #if 1//try change this to 0 int a[100]; boost::shared_ptr<int> p(a); std::cout << std::endl; #else int a[100]; delete a; // would terminate here std::cout << std::endl; #endif }

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[shared_ptr] class ... has pointer data members but does not override ...
by Klaus Backert 16 Oct '07

16 Oct '07

Hello, a Boost newbie question: Arch: PPC, OS: Mac OS X 10.4.10, Compiler: GCC 4.0.1 In a C++ dynamic library, I'm just developing, I have: #include <boost/shared_ptr.hpp> namespace MyNameSpace { typedef boost::shared_ptr<std::string> StringPtr; } I get the following warning: /usr/local/include/boost/shared_ptr.hpp: In instantiation of 'boost::shared_ptr<std::string>': /Volumes/blablabla/MyClass.cpp:81: instantiated from here /usr/local/include/boost/shared_ptr.hpp:131: warning: 'class boost::shared_ptr<std::string>' has pointer data members /usr/local/include/boost/shared_ptr.hpp:131: warning: but does not override 'boost::shared_ptr<std::string>(const boost::shared_ptr<std::string>&)' The incriminated line in MyClass.cpp is the second line here: __attribute__((visibility("default"))) MyNameSpace::StringPtr MyClass::myFunction() const { /* .......... */ } I have experienced the same with classes of my own instead of std::string, i.e. with typedef boost::shared_ptr<MyOtherClass> MyOtherClassPtr; etc. May be it's just me, but the boost documentation and Google don't help. Can I ignore the warnings or should I do something? Thanks in advance Klaus

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How to add a type to is_arithmetic
by Peng Yu 16 Oct '07

16 Oct '07

Hi, Suppose I define a class fixed_point as class fixed_point{ ....some operations are defined here private: int _integer_part; unsigned _fractional_part } I want is_arithmetic<fixed_point>::type to be true_ Of cause, I can partially specialize the template class as template <> struct is_arithmetic<fixed_point> { ... blah blah }; If I use the above approach, shall I put it into the namespace boost or not? Also, I'm wondering if there is any generic way to do this? Thanks, Peng

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[optional] documentation errors
by Edward Diener 16 Oct '07

16 Oct '07

In the 1.34.1 documentation for optional<T>, in the Synopsis section, it is currently written: -------------------------------------------------------------------------- template<class InPlaceFactory> explicit optional ( InPlaceFactory const& f ) ; template<class TypedInPlaceFactory> explicit optional ( TypedInPlaceFactory const& f ) ; AND template<class InPlaceFactory> optional& operator = ( InPlaceFactory const& f ) ; template<class TypedInPlaceFactory> optional& operator = ( TypedInPlaceFactory const& f ) ; -------------------------------------------------------------------------- Since InPlacefactory and TypedInPlacePlactory are actual classes, these should be: template<InPlaceFactory> explicit optional ( InPlaceFactory const& f ) ; template<TypedInPlaceFactory> explicit optional ( TypedInPlaceFactory const& f ) ; AND template<InPlaceFactory> optional& operator = ( InPlaceFactory const& f ) ; template<TypedInPlaceFactory> optional& operator = ( TypedInPlaceFactory const& f ) ; ------------------------------------------------------------------------- In the Detailed Semantics these are shown correctly.

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[fusion] subset view
by Chris Weed 16 Oct '07

16 Oct '07

Hi, I would like to make a subset view of the element in a tuple. It would, for example, give me a view into the first, third, and fifth element of the tuple. It isn't clear how to do this with the available views. Thanks, Chris

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[serialization]-- serialize binary data to a memory buffer?
by Rich Peters 16 Oct '07

16 Oct '07

I saw an example where boost serialized a text archive to a strstream for sending via a socket. I would like to do something similar, but for binary data. Is there a way to do the binary serialization to a memory buffer, and then send it elsewhere? It doesnt seem like strstream and boost::archive::binary_oarchive would mix correctly. I have also seen some discussion regarding a binary_iostreams library, but its doesnt look like that exists yet. thanks Rich

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Re: [Boost-users] [continued][boost::fusion v2 and xpressive] versioning conflicts...
by Ovanes Markarian 16 Oct '07

16 Oct '07

Eric, I changed the files. Should I zip them and post via mailinglist? Or should I submit them somewhere else? List of files which were changed: detail/core/linker.hpp detail/core/matcher/alternate_matcher.hpp detail/static/productions/alt_compilers.hpp detail/utility/any.hpp detail/utility/cons.hpp proto/op_base.hpp proto/proto_fwd.hpp xpressive.hpp One problem is that xpressive.hpp has info about boost version, but this is the mostly used file for inclusion. Therefore I believe this check fill fail even in boost 1.35: #if BOOST_VERSION >= 103500 # ifndef BOOST_XPRESSIVE_FUSION_V2 # define BOOST_XPRESSIVE_FUSION_V2 # endif //BOOST_XPRESSIVE_FUSION_V2 #endif //BOOST_VERSION I also executed your examples from the boost/lib directory and they produced in both cases same results. Your answer today is highly appreciated, since I will be on vacation from tomorrow on. thanks, Ovanes > On 9/24/07, Ovanes Markarian < om_boost(a)keywallet.com> wrote: > > > > Eric, > > > > sorry for the delay. I only now found some time to work on that issue: > > http://lists.boost.org/boost-users/2007/08/30120.php > > > > > > After analysing your post and investigation what's going on, I would > > like to write my opinion: > > > > changing xpressive_fwd.hpp or proto_fwd.will not help. > > > > I grepped where fusion includes are used and need to enclose these in > > some conditional statements: > > > > #ifdef BOOST_XPRESSIVE_FUSION_V2 > > # include ... //fusion 2 headers > > #else > > # include ... // fusion 1 headers > > #endif > > > > Actually this can be done using some kind of a macro function like: > > > > #include BOOST_XPRESSIVE_FUSION_ROOT(sequence/cons.hpp) > > ... > > > > The macro function will deliver the root dependent on the predefined > > macros like: > > 1. if !defined XPRESSIVE_FUSION_ROOT and use V2 > > => choose the root for V2 > > else => choose the root for V1 > > > > As I found out the following files need to be changed: > > linker.hpp > > alternate_matcher.hpp > > alt_compilers.hpp > > any.hpp > > cons.hpp > > arg_traits.hpp > > op_base.hpp > > proto_fwd.hpp > > > > If you give me your green light I will do it and submit a patch. > > > > > > With Kind Regards, > > Ovanes > > > > > >

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Problem using Boost Graph Library - Python Bindings
by Camilo La Rota 16 Oct '07

16 Oct '07

Hello all, I have just installed the Boost Graph Library - Python Bindings. Everything seemed to be ok, I can read a graph from the example "mst.dot" file and from my own ".dot" files, I can write them back to a file. However, when I try the example script (at the end of the following page: http://www.osl.iu.edu/~dgregor/bgl-python/) -------------------------------------------------------------------- import boost.graph as bgl # Load a graph from the GraphViz file 'mst.dot' graph = bgl.Graph.read_graphviz('mst.dot') # Convert the weight into floating-point values weight = graph.convert_property_map(graph.edge_properties['weight'], 'float') ... etc ------------------------------------------------------------------- it stops at the third line with the following error: ---------------------------------------------------------------------------- Traceback (most recent call last): File "<pyshell#17>", line 1, in <module> weight = graph.convert_property_map(graph.edge_properties['weight'],'float') KeyError: 'weight' ------------------------------------------------------------------------ I receive the same error message if I write only: graph.edge_properties['weight'] The content of the example mst.dot file is: -------------------------------------------------- graph G { A -- C [weight="1.0"] B -- D [weight="1.0"] B -- E [weight="2.0"] C -- B [weight="7.0"] C -- D [weight="3.0"] D -- E [weight="1.0"] E -- A [weight="1.0"] E -- B [weight="1.0"] } -------------------------------------------------- Does any one have any idea about the source of this error. Thanks a lot in advance, Camilo

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Re: [Boost-users] How to add a type to is_arithmetic
by Chad Walters 16 Oct '07

16 Oct '07

It's not entirely clear from your description if you really need to have is_arithmetic be true for your fixed_point class or if you just want to have some predicate that is true for both the built-in arithmetic types and your fixed_point class. If the former, then you will likely run afoul of problems, for the reasons previously pointed out. Hopefully it is the latter - in which case you should just define your own predicate with the appropriate logic (true for fixed_point or is_arithmetic types). Chad

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Retrieve number os affected rows
by Hamilton Vera 16 Oct '07

16 Oct '07

How to retrieve the number of affected rows after an update? ( I am testing in a MySQL database) I only found this in the list; http://lists.boost.org/Archives/boost/2006/12/114037.php But I was unable to find the sql.rowsaffected() fuction. I am using soci version 2.2.0. -- Hamilton Vera int Administrator (char Network[],char ComputationalSystems[]); Seven Internet http://lib.seven.com.br "Google is my shepherd, no want shall I know"

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[xpressive] crash...
by Ovanes Markarian 16 Oct '07

16 Oct '07

Hello Eric, this code fragment will crash, since 'what' uses iterators into the invalid string x::smatch what; if(x::regex_match(std::string(" (some_type_ptr) xyz,"), what, regex)) //string goes out of scope after this sentance { std::cout << what[0] << endl; // boom! string iterators are no longer valid std::cout << what[1] << endl; } May be there is a way to probit this kind of behaviour during the compilation or at least this can be stated in the docs... With Kind Regards, Ovanes

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[system] in multi-threaded context
by Jeroen van der Wulp 16 Oct '07

16 Oct '07

Hello, I have some problems with the latest changes to asio, which turn out to be caused by problems with boost::system. The newer versions of boost::asio now use boost::error_code provided by boost::system for error handling. On OS X 10.4 with XCode 2.4.1 comparing two boost::error_code objects e1 & e2 always returns false. I believe this is caused by comparing objects accross threads. But this is just a guess. A problem I noticed on with Apple's version of gcc is that static instance variables behave strange, there seems to be a copy for each variable in each compilation unit that uses them? This may also somehow be the cause for my problems with boost::system. Another problem is that when I receive an error_code object, say e, from asio, trying to print e.message() fails with an access violation. This happens on Windows, Linux, OS X. What am I doing wrong? Thanks, Jeroen van der Wulp

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[boost-users] enable_if and checking if class derives from boost::operators does not work.
by chun ping wang 16 Oct '07

16 Oct '07

namespace boost { template <class T, class U> char (& is_op_test(boost::operators<T,U> const&) )[2]; template <class T> char is_op_test(T const&); template<class T> T const& make(); template <class T> struct is_operators : boost::mpl::bool_<(sizeof(is_op_test(make<T>())) == 2)> {}; } and this function declaration. template <typename T, template <typename ELEM, typename = std::allocator<ELEM> > class CONT > typename boost::enable_if<boost::mpl::or_<boost::is_integral<T>, boost:: is_operators<T> >, CONT<T> >::type primelist(const T& MAX_BOUND, const T& K, boost::function<bool(const T&, const T&)> f); BigInteger class declaration looks like this.. class BigInteger : public BigUnsigned, boost::operators<BigInteger>, boost::operators<BigInteger, int> { }; I compile with T = int and it works. When i compile with T = BigInteger I get the following errors. on visual c++. error C2770: invalid explicit template argument(s) for 'boost::enable_if<boost::mpl::or_<boost::is_integral<T>,boost::is_operators<T> >,CONT<T>>::type primelist(const T &,const T &,boost::function<bool(const T &,const T &)>)' ./cs512/c++/primeMain.cpp(24) : see declaration of 'primelist'" on mingw dev-cpp i get this error. unable to find function.... In both cases passing BigInteger does not work. thanks for the help. BigInteger does derive from boost::operators and theirs two overload.

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[filesystem] vacpp errors building 1_34_1 filesystem library on AIX
by Marty Fried 15 Oct '07

15 Oct '07

I've built all the boost libraries on Windows and Red Hat, but there are compiler errors building on AIX using Visual Age (xlC) for the filesystem library. It builds using gcc, but not vacpp, which is the AIX standard compiler. We are using the latest version, V. 8. There is more than one error, but I think they are all similar. I believe that the code envolved is not fully standard compliant. For example, in operations.hpp, there is an error on line 732, col 72; the full error is (I tried to wrap as best I could): The declaration of "end_itr" uses the undefined class "boost::filesystem:: basic_directory_iterator<boost::filesystem::basic_path <std::basic_string<char,std::char_traits<char>,std::allocator<char> >, boost::filesystem::path_traits> >" when the class must be complete. The code is called by line 730, called by 473, called by 689. The problem, I think, is that basic_directory_iterator is not defined until line 822, after all these calls. A coworker created a simple test that reproduced this error, fed it into an online ANSI/ISO C++ Standard test utility by Comeau computing, and it flagged it as an error. Has anyone compiled 1_34_1 using xlC/vacpp? If you need more information, or need the other errors, let me know. -- Marty Fried Left Coast, USA

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boost-build-2.0-m11 and gcc-4.2.2
by Michael Albert 15 Oct '07

15 Oct '07

Greetings. If in "jam_src" I attempt to compile with gcc-4.2.2, the "bjam" executable compiles (using ./build.sh), but "bjam --version" fails on a segmentation fault. I can compile with gcc 3.4.6. Any thoughts? Anyone else seen this behavior? Thanks! -Mike

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[ Boost-users] [preprocessor] - introduce mpl { ... } like asm { ... }
by Frank Bergemann 15 Oct '07

15 Oct '07

Hi, i posted this to comp.lang.c++.moderated: ------------------------------------------------------- Hi, i am just starting to work with "C++ Template Metaprogramming" - using the book of David Abrahams & Aleksey Gurtovoy. And you know, there are things like mpl::plus<> for some operator, mpl::if_<> for a control-struct, mpl:insert<>, mpl:erase<>, mpl:clear<> for STL container like operations, etc. Lots of things re-modeled the "unaccustomed template-syntax" - way for types, which are there in C/C++ language definition already for operating on variables and values. So i wonder if it would be a good option to introduce some mpl { ... } in remembrance of asm { ... } This time not for going down to the assembler level, but going up to the meta level. But with the goal to drop the template fashioned syntax for meta programming by a syntax already familiar in C/C++ language without templates (if this is possible - i don't now enough about that). Well, this is just a gut feeling, that there might be a chance this way to more align "standard" programming with "meta" programming, which then might enable to easier catch the the gray area of borderline between compilation and runtime execution and how to shift that back and forth. What do you think? rgds! Frank ------------------------------------------------------- Then i was thinking, that instead of extending the C++ language, it might be sufficient to use an own preprocessor before handing over to g++ (e.g.). For this maybe using boost::spirit? Finally i was remembering, that there is already some 'preprocessor' project in boost itself. But having a 1st look at it, it doesn't seem to do what i'd like to have. Just as an example - see this extract from boost::enable_if documentation: template <class T> typename enable_if_c<boost::is_arithmetic<T>::value, T>::type foo(T t) { return t; } I'd like to make it s.th. like: mpl { template <class T> if (is_arithmetic(T)) { T foo (T t) { return t;} } } This is just a simple example. But just imagine use of mpl metafunctions like mpl::and_ mpl::or_, mpl::plus, mpl::minus, mpl::equal_to, mpl::less, etc, that could come back to the "natural" &&, ||, +, -, ==, <, etc. [ hmm, i think, i mixed up mpl::enable_if with mpl::if_ - so my example is not correct - but i hope you get my point here ] Them maybe it would also be possible somehow: mpl { template <class T> if (is_arithmetic(T)) { T foo (T t) { return t;} } else { #error "instantiation of foo() not supported for given type T" } } ... to generate usefulcompiler warning/errors. The main point for me is to get find an equivalent to the "strange" template syntax that is more C/C++ alike way to deal with variables and values. Not because template syntax is "strange". But in order to re-align again. rgds! Frank

3 2

[mpl][fusion] making a heterogeneous collection of classes from a list of types.
by Michael Marcin 15 Oct '07

15 Oct '07

Hello, I have the MPL book and I've used some metaprogramming before but I'm always at the edge of my understanding of the language when I do it. I have a problem right now which I suspect is trivial but I can't for the life of me figure out how to do it. I have a list of 25 resource types (class Sound, class Script, etc.) and since they are not mutable I want to share them so I have a resource cache template that looks something like: template< typename Resource > class Cache { public: typedef typename Tag<Resource>::type resource_tag; /// Retrieve a resource by id /// Throws cache_error if the resource couldn't be found in the Repository Resource& Retrieve( ResourceId id ) { // is the resource in the cache? typename ResourceMap::iterator it = m_resources.find( id ); if( it != m_resources.end() ) { return it->second; } else { return LoadResource( id ); } } /// Clears the cache and destructs all cached resources. void Clear() { m_resources.clear(); } private: Resource& LoadResource( ResourceId id ) { Stream stream( Repository::Instance().Retrieve( id, resource_tag::type::value ) ); if( !stream.fail() ) { Resource* res = new Resource(stream); m_resources.insert( id, res ); return *res; } else { throw cache_error( id, resource_tag::type::value ); } } typedef boost::ptr_map< ResourceId, Resource > ResourceMap; ResourceMap m_resources; }; I have a class which must contain a Cache for each of the 25 resource types and support calls to get a resource of a particular type given an id and be able to call Clear on all 25 caches. Something like class Manager { public: /// Returns Cache<Resource>::Retrieve( id ) template< typename Resource > const Resource& Get( ResourceId id ); /// Calls Cache::Clear for all resource types void Clear(); }; It would be pretty easy to just copy and paste it out 25 times but I would like to reduce code duplication and simplify maintenance through metaprogramming. I have a private boost::mpl::list25 named resource_list containing all the resource types. I think I need to transform that in to a boost::fusion::map of 25 Resource to Cache<Resource> pairs but I'm not sure that is what I really need to do or how to go about doing that. Thanks, Michael Marcin

2 6

Header error in boost/python/object/make_holder?
by Michel Valstar 15 Oct '07

15 Oct '07

Hello, I am trying to build code of a recently graduated student, who is now unavailable to us (read: ignores us). When running scons in the appropriate directory, a lot gets build, until I get the following error: /usr/include/boost/python/object/make_holder.hpp:81: error: 'allocate' is not a member of 'boost::python::objects::value_holder<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, State> >' /usr/include/boost/python/object/make_holder.hpp:83: error: no matching function for call to 'boost::python::objects::value_holder<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, State> >::value_holder(int*&)' /usr/include/boost/python/object/value_holder.hpp:44: note: candidates are: boost::python::objects::value_holder<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, State> >::value_holder() /usr/include/boost/python/object/value_holder.hpp:44: note: boost::python::objects::value_holder<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, State> >::value_holder(const boost::python::objects::value_holder<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, State> >&) scons: *** [trackerbase/trackerbasewrapper.os] Error 1 scons: building terminated because of errors. This does not seem to be an error in his own code, rather an error in the boost.python code? This is the first time I am using boost, and, as usual, I need to get this program working yesterday. My machine is a recently installed Ubuntu Feisty (hence the need for re-compilation). I am using the latest version of Boost (boost_1_34_1) and python 2.5.1 Any help would be appreciated. Thanks, MIchel -- Michel Valstar, PhD candidate http://www.doc.ic.ac.uk/~mvalstar Department of Computing Imperial College London 180 Queens' Gate London SW7 2AZ, U.K. tel.: +44 20 7594 8225 fax: +44 20 7581 8024

2 1

[serialization]-- serialize a std::vector<>?
by Rich Peters 15 Oct '07

15 Oct '07

Hello, sorry for the newbie questions... I have some sample serialization code where I serialize a container. if that container is std::list<sometype> it works fine. the same code with a std::vector<sometype> fails to compile. are vectors supported for serialization? I cant find any specific mention in the documentation or via searching. thanks

2 1

[ptr_map]const_iterator does not represent value_type
by Bill Buklis 15 Oct '07

15 Oct '07

In ptr_map, const_iterator does not represent value_type. Given this map: typedef boost::ptr_map<DWORD, int> BOOSTMAP; BOOSTMAP::value_type equates to: boost::ptr_container_detail::ref_pair<DWORD, int* const> BOOSTMAP::iterator does return this, but const_iterator returns: boost::ptr_container_detail::ref_pair<DWORD, const int* const> which is unlike std::map which represents const value_type for const_iterator. Since this is a different structure, it's incompatible with BOOSTMAP::value_type. The following code works using std::map: typedef std::map<DWORD, int*> STDMAP; int sample = 5; STDMAP sm; sm.insert( STDMAP::value_type(10,&sample) ); STDMAP::iterator sfirst = sm.begin(); STDMAP::const_iterator scfirst = sm.begin(); STDMAP::value_type& svt = *sfirst; const STDMAP::value_type& scvt = *scfirst; But, the same fails on the last line with boost::ptr_map typedef boost::ptr_map<DWORD, int> BOOSTMAP; BOOSTMAP bm; DWORD key = 10; bm.insert( key, new int(5) ); BOOSTMAP::iterator bfirst = bm.begin(); BOOSTMAP::const_iterator bcfirst = bm.begin(); BOOSTMAP::value_type& bvt = *bfirst; const BOOSTMAP::value_type& bcvt = *bcfirst; Also, it is not possible to bind to one of the members BOOSTMAP::value_type. For example, this works with std::map, but fails with ptr_map: boost::bind( &BOOSTMAP::value_type::first, _1 ); -- Bill --

1 0

[tools/regression] Directory reorganization
by Beman Dawes 15 Oct '07

15 Oct '07

There's some reorganization in progress in the trunk/tools/regression directory. This shouldn't affect most developers or users, since any of our Boost scripts that depend on these directory locations are being updated too. But if you've got any of your own scripts, make files, or IDE projects that depend on these directory locations, you will need to update them accordingly. Thanks to Rene Rivera for cleaning up this aspect of our tools directory structure! --Beman

1 0

Build Problem: bjam + boost + python
by Michael Bradley Jr 15 Oct '07

15 Oct '07

Hi, I've done a svn check_out of the boost repository. I'm trying to build it with the underlaying options, but can't achieve that goal due to the underlaying error messages. Any help or hints will be appreciated Cheers Michael ps A couple of weeks ago, i was able to compile boost with the same options without a problem. "bin/bjam.exe" -d 0 stage --stagedir=. --toolset=msvc link=sta tic runtime-link=shared architecture=x86 release debug address-model=32 warning: Graph library does not contain optional GraphML reader. note: to enable GraphML support, set EXPAT_INCLUDE and EXPAT_LIBPATH to the note: directories containing the Expat headers and libraries, respectively. warning: skipping optional Message Passing Interface (MPI) library. note: to enable MPI support, add "using mpi ;" to user-config.jam. note: to suppress this message, pass "--without-mpi" to bjam. note: otherwise, you can safely ignore this message. Building Boost.Regex with the optional Unicode/ICU support disabled. Please refer to the Boost.Regex documentation for more information (don't panic: this is a strictly optional feature). error: Unable to find file or target named error: '/python//python_for_extensions' error: referred from project at error: 'libs/python/build'

1 0

[boost-users][system] Mixing non-errors and errors (status_code vs. error_code)
by Darren Garvey 15 Oct '07

15 Oct '07

Hello, I've been wondering for a while if it's sensible to use Boost.System for transporting status_codes, rather than strictly error_codes. I'm aware than I *may* be trying to misuse the system library here, so I'll get straight to an example: If I had an HTTP library that retrieved remote pages, I might want to use, as (a very crude) example: template<typename MutableBufferSequence> void get_page(http::connection& conn, MutableBufferSequence& buf) { boost::system::error_code ec; conn.get_page(buf, ec); if (ec) throw ec; } The problem with relying on error_code to carry the errors is that the various success codes (eg. 200 OK, 201 ACCEPTED, 202 CREATED, etc.) seem to get lost, unless you class them as errors. Then you'd need something like: - if (ec) throw ec; + if (ec >= http::ok || ec <= http::multi_status) throw ec; It's not a massive pain, but having `ec == true` even when you don't have an error isn't helpful. AFAICT, any non-zero error value is an error that'll give `ec == true`. I feel like I'm missing something here, please tell me if I am. Regards, Darren PS. I'm trying to avoid having to make something that lies on top of boost::system::error_code, like a status_code class.

1 0

[Serialization] Example for Boost.Any
by Joseph Lisee 15 Oct '07

15 Oct '07

Hello, 2 years ago on this list there was a discussion on how to serialize/deserialize a Boost.Any variable. I read through and found some proposals, but never any implementations. I was wondering whether anyone had ever gotten around to implementing it? I have no qualms about using a custom Boost.Any with serialization support coded in. -Joe

1 0

what::runtime_error::std already defined
by Lars Schouw 15 Oct '07

15 Oct '07

I am getting these linking errors and can't figure out where it comes from. 4>libboost_regex-vc80-mt-gd-1_34_1.lib(instances.obj) : error LNK2005: "public: virtual char const * __thiscall std::runtime_error::what(void)const " (?what@runtime_error@std@@UBEPBDXZ) already defined in Curve.obj I am using Visual Studio 2005 SP1 and Windows XP Lars ____________________________________________________________________________________ Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games. http://sims.yahoo.com/

1 0

[program_options] Dynamic linking broken with VS7.1
by Robert Brueckmann 15 Oct '07

15 Oct '07

I tried to compile a simple test program, but it doesn't link dynamically. Any suggestions, what I'm doing wrong? I'm using boost 1.34.1 prebuilt libs from boost-consulting and MSVC 7.1. The test code which fails: #include <boost/program_options.hpp> namespace po = boost::program_options; int main(int argc, char** argv) { unsigned int i1; po::options_description normal_options("parameters"); normal_options.add_options() ("test,t", po::value<unsigned int>(&i1)->default_value(0), "test") ; return 0; } I compile using the following command: cl /TP /EHsc /nologo /GR /WL /W2 /Od /MDd /GS /Z7 /DBOOST_ALL_NO_LIB /Ih:\repos\trunk\3rd\include\common\boost\1_34_1 /c main.cpp /Fomain.obj The linker command link /nologo /OUT:test.exe /LIBPATH:h:\repos\trunk\3rd\lib\win32\cl\13.10\boost\1_34_1 boost_program_options-vc71-mt-gd-1_34_1.lib /DEBUG main.obj fails with the error message main.obj : error LNK2001: unresolved external symbol "class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > boost::program_options::arg" (?arg@program_options@boost@@3V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@A) However, when linking statically using link /nologo /OUT:test.exe /LIBPATH:h:\repos\trunk\3rd\lib\win32\cl\13.10\boost\1_34_1 libboost_program_options-vc71-mt-gd-1_34_1.lib /DEBUG main.obj then everything is working... Any ideas? Thank you in advance, Robert

1 0

[Iostreams] stream not clearing state
by Benjamin Collins 14 Oct '07

14 Oct '07

I'm trying to use a stream and open/close the underlying device on the fly. Here's my test code: #include <iostream> #include <boost/filesystem.hpp> namespace fs = boost::filesystem; #include <boost/iostreams/device/mapped_file.hpp> #include <boost/iostreams/stream.hpp> namespace io = boost::iostreams; namespace { const uint32_t block_size = io::mapped_file_source::alignment(); } bool test1() { io::mapped_file_params mfp("rand.bin"); mfp.mode = std::ios_base::in | std::ios_base::binary; mfp.length = block_size; io::mapped_file mf(mfp); io::stream<io::mapped_file> in(mf); int blocks = fs::file_size("rand.bin")/block_size; if (fs::file_size("rand.bin") % block_size) ++blocks; for (int i=0;i<blocks;++i) { in->close(); mfp.offset = block_size*i; std::cout << "mapping bytes [" << block_size*i << " - " << block_size*(i+1) - 1 << "]\n"; in->open(mfp); in.clear(); std::cout << "stream is in state: [ "; if(in.rdstate() | std::ios::goodbit) std::cout << "good "; if(in.rdstate() | std::ios::badbit) std::cout << "bad "; if(in.rdstate() | std::ios::failbit) std::cout << "fail "; if(in.rdstate() | std::ios::eofbit) std::cout << "eof "; std::cout << "]\n"; int count=0; char x; while(!in.eof()) { if(io::stream<io::mapped_file>::traits_type::eof() == (x = in.get())) throw std::runtime_error("unexpected eof"); std::cout << '.'; ++count; } if(0==count) throw std::runtime_error("unable to read characters in this map"); else std::cout << count << "bytes read.\n"; } } If you don't like to see code in email, see here: http://pastebin.com/m40e9432b This program prints the following: ------------------------------------------------ mapping bytes [0 - 4095] stream is in state: [ bad fail eof ] terminate called after throwing an instance of 'std::runtime_error' what(): unexpected eof Aborted So what gives? Why isn't boost::iostreams::stream clearing its state properly? -- Benjamin A. Collins <ben.collins(a)acm.org> http://bloggoergosum.us

1 0

[BGL] Inverse property mapping?
by "Alejandro M. Aragón" 14 Oct '07

14 Oct '07

Hello everyone, I've been looking for some time at the documentation and I couldn't find a single way to obtain an inverse mapping for a property map. That is, given a property p, I would like to obtain a vertex descriptor v. It seems that the mapping is only in one direction. Is there a way to obtain the inverse mapping too? If so, what is the complexity associated with obtaining the vertex descriptor? Thank you, a²

3 3

[serialization]-- boost integrated with MFC Doc/View?
by Rich Peters 13 Oct '07

13 Oct '07

I am looking at boost serialization and it looks very good. Has anyone tried to integrate boost serialization with MFC Doc/View CArchive serialization? I would be interested to hear how you did it. Can a CArchive be turned into a istream or ostream that could be used? thanks

2 1

ptr_set problems
by Surya Kiran Gullapalli 13 Oct '07

13 Oct '07

Hello, I'm using ptr_set for one of my classes whose structure is like this. =============================== using namespace boost; class A: less_than_comparable<A>, equality_comparable<B>, noncopyable { friend operator< (const A&, const A&) ; public: A() virtual ~A () virtual void fun1() = 0 ; } class B: public A { public: B () ; ~B () ; virtual void fun1() { cout << "Func1 in B" << endl ; } } class C : public A { public: C () ; ~C () ; virtual void fun1() { cout << "Func1 in C" << endl ; } } ============================================== and I'm inserting into ptr_set like this. A *varb = new B () ; A *varc = new C() ; ptr_set <A> Aset ; Aset.insert (varb) ; Aset.insert (varc) ; **************** Compilation is fine on windows (VS2005) and linux (gcc-4.1.2) On linux, the code executes fine. But on windows, I'm getting a DEBUG ASSERTION failure during insertion. The failure says, Expression: invalid operator<. This happens in debug version only. In release version, the code executes fine on windows also. Any help on how to attack this problem is greatly appreciated. Thanks in advance, Surya

2 1

Making an ordinary function into something useful in lambda expressions
by Peter Waller 13 Oct '07

13 Oct '07

I wish to write some lambda functions to have this sort of behaviour. #include <lambda/lambda.hpp> #include <lambda/bind.hpp> #include <function.hpp> using namespace boost::lambda; using namespace boost; #include <iostream> using std::cout; using std::endl; #include <cmath> int main( int argc, char *argv[] ) { float value; var_type<float>::type theValue( var( value ) ); // Ignore this line #define cos(theta) bind( unlambda(bind( cos, _1 )), theta ) function<float ( float )> myfunction = ( cos( theValue ) - 1 ); value = 2; cout << "The result = " << myfunction(1) << endl; return 0; } Namely, the cos( value ) part. The code above works, but I feel that using a #define is a little messy, and seems hard to generalise to functions with more arguments. I was wondering if there was a general, better way of turning a given function into one whose execution is delayed. Thanks in advance, - Peter

3 3

[boost-users][function, assign] error C2986 and C2784 on visual studio 2005 .
by chun ping wang 13 Oct '07

13 Oct '07

So given this header. template < QSTYPE type, typename T, template <typename ELEM, typename = std::allocator<ELEM> > class CONT > CONT<T> quicksort(CONT<T>); // inside the main file. // I decided a function that takes vector of integer and returns a vector of integer. typedef boost::function<std::vector<int>(std::vector<int>)> sortfunc; // create a function list to hold the sorting function. // bunch of number include. #include <boost/assign/std/vector.hpp> std::vector<sortfunc> function_list; using boost::assign::operator+=; std::vector<sortfunc> function_list; // quicksort random function_list += (&algocpw::quicksort<algocpw::QSTYPE(algocpw::RANDOM), int, std::vector>), // quicksort median (&algocpw::quicksort<algocpw::QSTYPE(algocpw::MEDIAN), int, std::vector>), // quicksort mediantriple (&algocpw::quicksort<algocpw::QSTYPE(algocpw::MEDIANTRIPLE), int, std::vector>), // merge sort (&algocpw::mergesort<int, std::vector>), // heap sort (&algocpw::heapsort<int, std::vector>), // selection sort (&algocpw::selection_sort<int, std::vector>), // standard sort (&algocpw::standard_sort<int, std::vector>); I get the following errors. ./cs512/c++/sortingMain.cpp(63) : error C2896: 'boost::assign::list_inserter<boost::assign_detail::call_push_back<std::vector<_Ty,_Alloc>>,V> boost::assign::operator +=(std::vector<_Ty,_Alloc> &,V2)' : cannot use function template 'CONT<T> algocpw::mergesort(CONT<T>)' as a function argument c:\cpw\msvc\cs512\c++\def\../sortingAlgo.hpp(32) : see declaration of 'algocpw::mergesort' ./cs512/c++/sortingMain.cpp(63) : error C2784: 'boost::assign::list_inserter<boost::assign_detail::call_push_back<std::deque<T,Allocator>>,V> boost::assign::operator +=(std::deque<T,Allocator> &,V2)' : could not deduce template argument for 'std::deque<T,Allocator> &' from 'std::vector<_Ty>' with [ _Ty=sortfunc ] Where did "deque" come from.. i never included deque.

1 0

[ANN] Xpressive 2.0.0
by Eric Niebler 12 Oct '07

12 Oct '07

Xpressive has just reached 2.0! The new version has lots of cool new features (see below). Subversion and the File Vault both have the latest code. It works with HEAD and with Boost v1.34.1. Below is an earlier message announcing the feature set of xpressive 2.0. The latest docs are here: http://boost-sandbox.sourceforge.net/libs/xpressive/doc/html/index.html Also, xpressive.zip in the File Vault (Strings - Text Processing directory) contains the docs in pdf format. Please grab the latest code and let me know of any problems you encounter so I can get them fixed for 1.35. -- Eric Niebler Boost Consulting www.boost-consulting.com Eric Niebler wrote: > It's a poorly kept secret that I've been adding new features to > Xpressive on CVS HEAD for a while now. So here are the features already > implemented (documentation forthcoming) for Xpressive 2.0: > > << Semantic Actions >> > > Specify code to execute when parts of a regex match, a-la Spirit's > semantic actions. Eg.: if you want to parse a string of name/value pairs > into a std::map, you might: > > std::map<std::string, int> result; > std::string str("aaa=>1 bbb=>23 ccc=>456"); > > // Like "(\\w+)=>(\\d+)": > sregex pair = ( (s1= +_w) >> "=>" >> (s2= +_d) ) > [ ref(result)[s1] = as<int>(s2) ]; > sregex rx = pair >> *(+_s >> pair); > > if(regex_match(str, rx)) > { > assert(result["aaa"] == 1); > assert(result["bbb"] == 23); > assert(result["ccc"] == 456); > } > > The actions are placed on a queue and executed in order only when the > regex match succeeds. > > << Custom Assertions >> > > Use the check() function to create a boolean predicate that can > participate in the match. Here's a regex that recognizes two integers > only if the first is less than the second: > > sregex rx = ( (s1= +_d) >> ' ' >> (s2= +_d) ) > [ check( as<int>(s1) < as<int>(s2) ) ]; > > Unlike actions, predicates execute immediately. You can also define the > predicate out-of-line as a function object. > > << Dynamic Regex Grammars with Named Regexes >> > > Using regex_compiler, you can map a name to a regex object, and then > refer to that regex from another by name. In this way, you can build > grammars from regexes at runtime. > > sregex_compiler comp; > sregex rx = comp.compile("^bar(?$RE)baz$"); > comp.compile("(?$RE=)\\d+ \\d+"); > > There's an alternate syntax for associating a name with a regex that you > can use to nest a static regex in a dynamic one. Eg., the last line > above could be: > > comp["RE"] = +_d >> ' ' >> +_d; > > With these changes, you can now nest static and dynamic regexes within > each other freely, giving you lots of flexibility to build grammars and > modify them on the fly. > > << Named Captures >> > > For dynamic regular expressions, you can create a named capture with > (?P<name> ...). You can refer back to the named capture with (?P=name). > In substitution strings (for use with regex_replace()), you can refer > back to a named capture with \\g<name> when using the format_perl or > format_all flags. > > And more .... I'd like to give props to Dave Jenkins who has been doing > m4d things with this stuff already, and who has given me a laundry list > of other features he'd like.

1 0

Re: [Boost-users] Container iteration macro that is equivalent tohandcoded iteration?
by John Femiani 12 Oct '07

12 Oct '07

> -----Original Message----- > From: John Femiani > Sent: Wednesday, October 10, 2007 3:16 PM > To: 'boost-users(a)lists.boost.org' > Subject: RE: [Boost-users] Container iteration macro that is equivalent > tohandcoded iteration? > > > > -----Original Message----- > > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users- > > bounces(a)lists.boost.org] On Behalf Of Michael Marcin > > Sent: Wednesday, October 10, 2007 1:07 PM > > To: boost-users(a)lists.boost.org > > Subject: Re: [Boost-users] Container iteration macro that is equivalent > > tohandcoded iteration? > > > > Erik wrote: > > > I have a lot of handcoded loops that look something like this: > > > > > > //////////////////////////////////////////////////////////////////////// // > > //// > > > #include <vector> > > > > > > void f(float); > > > void g(std::vector<float> const & v) { > > > std::vector<float>::const_iterator const v_end = v.end(); > > > for (std::vector<float>::const_iterator it = v.begin(); it != > v_end; > > ++it) > > > f(*it); > > > } > > > > > > //////////////////////////////////////////////////////////////////////// // > > //// > > > > > > I need to replace it with something equivalent but simpler. I tried > > > BOOST_FOREACH (from boost-1.34): > > > > > > //////////////////////////////////////////////////////////////////////// // > > //// > > > #include <boost/foreach.hpp> > > > > > > #include <vector> > > > > > > void f(float); > > > void g(std::vector<float> const & v) { > > > BOOST_FOREACH(float i, v) > > > f(i); > > > } > > > > > > //////////////////////////////////////////////////////////////////////// // > > //// > > > > > > But when I compared the assembly output of this with that of the > > > handcoded version I discovered that the boost version is more > > > complicated, so I tried to create something better myself, with the > > > requirement that the generated code is not allowed to be any more > > > complicated than that of the handcoded loop. The following is the best > I > > > could think of right now: > > > > > > //////////////////////////////////////////////////////////////////////// // > > //// > > > #define iterate_vector_const(value_type, it, v) > \ > > > for > \ > > > (struct { > \ > > > std::vector<value_type>::const_iterator current; > \ > > > std::vector<value_type>::const_iterator const end; > \ > > > value_type const & operator*() {return *current;} > \ > > > } it = {v.begin(), v.end()}; > \ > > > it.current != it.end; > \ > > > ++it.current) > \ > > > > > > #include <vector> > > > > > > void f(float); > > > void g(std::vector<float> const & v) { > > > iterate_vector_const(float, it, v) > > > f(*it); > > > } > > > > > > //////////////////////////////////////////////////////////////////////// // > > //// > > > > > > I looked at the difference between my macro and the handcoded loop: > > > $ diff -U2 iteration-handcoded-g++-4.2.0-O3.S iteration- > iterate_vector- > > g++-4.2.0-O3.S > > > --- iteration-handcoded-g++-4.2.0-O3.S 2007-10-07 19:38:56.000000000 > > +0200 > > > +++ iteration-iterate_vector-g++-4.2.0-O3.S 2007-10-07 > > > 20:00:53.000000000 +0200 > > > @@ -1,3 +1,3 @@ > > > - .file "iteration-handcoded.cc" > > > + .file "iteration-iterate_vector.cc" > > > .text > > > .align 2 > > > @@ -18,7 +18,7 @@ > > > .LCFI4: > > > movl 8(%ebp), %eax > > > - movl 4(%eax), %esi > > > movl (%eax), %ebx > > > - cmpl %ebx, %esi > > > + movl 4(%eax), %esi > > > + cmpl %esi, %ebx > > > je .L4 > > > .p2align 4,,7 > > > > > >>From this I conclude that my macro is as good as a handcoded loop. > > > (Although I of course wonder why the compiler chose to move "movl > > > 4(%eax), %esi" further down and swap the parameters of cmpl from > "%ebx, > > > %esi" to "%esi, %ebx".) > > > > > > But my macro is not as versatile as BOOST_FOREACH. Is there any way to > > > improve it? In particular, is it possible get rid of the macro > parameter > > > value_type? Is it possible to make it work with other containers than > > > vectors, as long as they define const_iterator/iterator, begin, end > and > > > value_type? Something like this maybe: > > > > > > //////////////////////////////////////////////////////////////////////// // > > //// > > > #define iterate_container_const(it, v) > \ > > > for > \ > > > (struct { > \ > > > typeof(v)::const_iterator current; > \ > > > typeof(v)::const_iterator const end; > \ > > > typeof(v)::value_type const & operator*() {return *current;} > \ > > > } it = {v.begin(), v.end()}; > \ > > > it.current != it.v_end; > \ > > > ++it.current) > \ > > > > > > #include <vector> > > > > > > void f(float); > > > void g(std::vector<float> const & v, std::list<float> const & l) { > > > iterate_containter_const(it, v) > > > f(*it); > > > iterate_containter_const(it, l) > > > f(*it); > > > } > > > > > > //////////////////////////////////////////////////////////////////////// // > > //// > > > > > > Or is it possible to configure BOOST_FOREACH to be as efficient as my > > macro? > > > > I don't know but that is a good question. > > > > I considered using BOOST_FOREACH until I checked its generated output... > > which was worse than std::for_each with a boost::bind which was worse > > than std::for_each with a hand coded functor which was worse than a hand > > coded for loop like yours above. > > > > - Michael Marcin > > > > p.s. Compilers make me sad > > > > _______________________________________________ > > Boost-users mailing list > > Boost-users(a)lists.boost.org > > http://lists.boost.org/mailman/listinfo.cgi/boost-users > > I think you will need to pass SOME type unless you are comfortable with > BOOST_AUTO or BOOST_TYPEOF. I think the problem is on some compilers they > require each type to be 'registered'. > > Maybe if you use a NEXT macro as well things will work out, because you > can put multiple braces in the next macro. > > #define FOREACH(X, COL, COLT) \ > { \ > COLT& __col__ = (COL); \ > for (iterator_type<COLT>::type __i__ = begin(__col__); \ > __i__ != end(__col__);\ > ++__i__) \ > { \ > X = *__i__; \ > { > > #define NEXT() \ > }\ > }\ > } > > > I haven't tried this, but it seems like one could do: > > #define FOREACH(X, COL) \ > { \ > BOOST_TYPEOF(COL)& __col__ = (COL); \ > BOOST_AUTO(__cur__, boost::begin(__col__)); > BOOST_AUTO(__end__, boost::end(__col__)); > for (; __cur__ != __end__; ++__cur__) \ > { \ > X = *__cur__; \ > { > > #define NEXT() \ > }\ > }\ > } > > Then you could use it like: > > vector<int> vec; > > FOREACH(int x, vec){ > > //do something with x > > }NEXT(); > > Or if BOOST_AUTO doesn't work it is > > vector<int> vec; //vector<int> does not have a comma in the type name! > > FOREACH(int x, vec, vector<int>) { > > //do something with x > > }NEXT(); > > > I have no idea how well BOOST_AUTO will work though. You would also need a > TPL version I think. > > IN my own code I have a special concern because I deal with half_edge > structures where begin()==end() and I need to do a bottom testing loop. > In these cases I made iteration macros for each container: I.e. > > MY_FOREACH_VERTEX_EDGE(e, vertex){ > //e is an edge iterator > }MY_NEXT_VERTEX_EDGE() > > > I found that to be readable. I did not use BGL stuff because I did not > know how to deal with begin() == end(). > > > -- John That is, unless you can understand the magic that makes BOOST_FOREACH work. :) -- John

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Container iteration macro that is equivalent to handcoded iteration?
by Erik 12 Oct '07

12 Oct '07

I have a lot of handcoded loops that look something like this: ////////////////////////////////////////////////////////////////////////////// #include <vector> void f(float); void g(std::vector<float> const & v) { std::vector<float>::const_iterator const v_end = v.end(); for (std::vector<float>::const_iterator it = v.begin(); it != v_end; ++it) f(*it); } ////////////////////////////////////////////////////////////////////////////// I need to replace it with something equivalent but simpler. I tried BOOST_FOREACH (from boost-1.34): ////////////////////////////////////////////////////////////////////////////// #include <boost/foreach.hpp> #include <vector> void f(float); void g(std::vector<float> const & v) { BOOST_FOREACH(float i, v) f(i); } ////////////////////////////////////////////////////////////////////////////// But when I compared the assembly output of this with that of the handcoded version I discovered that the boost version is more complicated, so I tried to create something better myself, with the requirement that the generated code is not allowed to be any more complicated than that of the handcoded loop. The following is the best I could think of right now: ////////////////////////////////////////////////////////////////////////////// #define iterate_vector_const(value_type, it, v) \ for \ (struct { \ std::vector<value_type>::const_iterator current; \ std::vector<value_type>::const_iterator const end; \ value_type const & operator*() {return *current;} \ } it = {v.begin(), v.end()}; \ it.current != it.end; \ ++it.current) \ #include <vector> void f(float); void g(std::vector<float> const & v) { iterate_vector_const(float, it, v) f(*it); } ////////////////////////////////////////////////////////////////////////////// I looked at the difference between my macro and the handcoded loop: $ diff -U2 iteration-handcoded-g++-4.2.0-O3.S iteration-iterate_vector-g++-4.2.0-O3.S --- iteration-handcoded-g++-4.2.0-O3.S 2007-10-07 19:38:56.000000000 +0200 +++ iteration-iterate_vector-g++-4.2.0-O3.S 2007-10-07 20:00:53.000000000 +0200 @@ -1,3 +1,3 @@ - .file "iteration-handcoded.cc" + .file "iteration-iterate_vector.cc" .text .align 2 @@ -18,7 +18,7 @@ .LCFI4: movl 8(%ebp), %eax - movl 4(%eax), %esi movl (%eax), %ebx - cmpl %ebx, %esi + movl 4(%eax), %esi + cmpl %esi, %ebx je .L4 .p2align 4,,7 >From this I conclude that my macro is as good as a handcoded loop. (Although I of course wonder why the compiler chose to move "movl 4(%eax), %esi" further down and swap the parameters of cmpl from "%ebx, %esi" to "%esi, %ebx".) But my macro is not as versatile as BOOST_FOREACH. Is there any way to improve it? In particular, is it possible get rid of the macro parameter value_type? Is it possible to make it work with other containers than vectors, as long as they define const_iterator/iterator, begin, end and value_type? Something like this maybe: ////////////////////////////////////////////////////////////////////////////// #define iterate_container_const(it, v) \ for \ (struct { \ typeof(v)::const_iterator current; \ typeof(v)::const_iterator const end; \ typeof(v)::value_type const & operator*() {return *current;} \ } it = {v.begin(), v.end()}; \ it.current != it.v_end; \ ++it.current) \ #include <vector> void f(float); void g(std::vector<float> const & v, std::list<float> const & l) { iterate_containter_const(it, v) f(*it); iterate_containter_const(it, l) f(*it); } ////////////////////////////////////////////////////////////////////////////// Or is it possible to configure BOOST_FOREACH to be as efficient as my macro?

10 17

[review] Exception - review period extended
by Tobias Schwinger 12 Oct '07

12 Oct '07

The review period of the proposed Exception library has been extended until October 20th. Although several people seemed interested in the submission, we only have two votes, so far. So we really need more votes. Further, I'm concerned about some potential issues, which I wouldn't want to bless into Boost without being sure there has been a thorough investigation (see below). So, I want to encourage you to evaluate the submission, in particular regarding the following questions: 1. Should the library be accepted as a Boost library? For a guideline on what to include in your evaluation see http://www.boost.org/more/formal_review_process.htm 2. Is the design of the 'enable_error_info' function (see http://www.revergestudios.com/boost-exception/boost-exception.htm#existing_… and http://www.revergestudios.com/boost-exception/boost-exception.htm#enable_er… ), using multiple inheritance, really sound? 3. Does the current implementation use appropriate data structures? We are looking forward to your reviews! Regards, Tobias Schwinger - Review Manager -

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[serialization] shared libraries & extended_type_info registration
by Vincent Agnus 12 Oct '07

12 Oct '07

Hi, I have some trouble about extended_type_info registration using BOOST_CLASS_EXPORT macro with shared library. Indeed an assertion forbides the registration of the same extended_type_info many times. This cases occurs when defining serialization of derivated classes in different libraries for example considers the 2 libraries : * the first one define a class and its serialization scheme * the second one define a class derived from the class in the first libs and its serialization scheme A program using this two libraries to serialize classes raise an assertion at runtime due to double registration of the base class [ file serialization/extended_type_info.cpp line 74 // make sure that attempt at registration is done only once assert(lookup(eti) == m_self->m_map.end()); ] Here the detail implementation of libraries LIB1 * files : Base.hpp ; Base.cpp defining a base class ( no serialization code here) * file : BaseSerilization.hxx which contains the definition of the non intrusive template function serialize ( no macro BOOST_CLASS_EXPORT here ) * file BaseSerilizationInstanciation.cpp which explicit instanciate the previous function with a fixed Archive class, this file also contain the macro BOOST_CLASS_EXPORT(Base) LIB2 * file Derivated.hpp, Derivated.cpp defining derivated class from Base ( no serialization code here) * file : DerivatedSerilization.hxx which contains the definition of the non intrusive template function serialize ( no macro BOOST_CLASS_EXPORT here ) ** #include "lib1/BaseSerilization.hxx" ** in fonction serialize .... use of base_object< lib1::Base > * file DerivatedInstanciation.cpp which explicit instanciate the previous function with a fixed Archive class, this file also contain the macro BOOST_CLASS_EXPORT(Derivated) a program using these 2 libraries raise an assertion file serialization/extended_type_info.cpp line 74. Indeed the macro BOOST_CLASS_EXPORT(Base) register the extended_type_info of Base. the macro BOOST_CLASS_EXPORT(Derivated) register the extended_type_info of Base *and* the void_caster register in serialize(... Derivated ...) register *again* Base class raising the assertion. So I have some questions 1. Is my design correct ? My programme work fine (Linux&Windows) in release mode. 2. why forbides multi-registration of the same extended_type_info ? 3. what is the interest using std::multiset for unique element instead std::set for tkmap::m_map type ? Regards, Vincent Agnus

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[signal,bind] upgrade problem from 1.33 to 1.34
by David Angelo 12 Oct '07

12 Oct '07

Hi folks, I have a problem with upgrading from boost version 1.33 to 1.34. My code runs fine with 1.33, but when compiling and linking againt 1.34 I get the following runtime error (backtrace): <backtrace> #0 0x81d4c9b2 in void boost::function1<void, float, std::allocator<void> >::ass ign_to<boost::_bi::bind_t<void, boost::_mfi::mf1<void, fpCTPart, float>, boost:: _bi::list2<boost::_bi::value <fpCTPart*>, boost::arg<1> (*)()> > >(boost::_bi::bi nd_t<void, boost::_mfi::mf1<void, fpCTPart, float>, boost::_bi::list2<boost::_bi ::value<fpCTPart*>, boost::arg<1> (*)()> >)::stored_vtable () from /home/david/eclipseM6/toolManagement/lib/libfpCTToolPack.so #1 0xb4438841 in boost::function0<void, std::allocator<void> >::clear ( this=0xa1a03fc) at /usr/include/boost/function/function_template.hpp:388 #2 0xb4438879 in ~function0 (this=0xa1a03fc) at /usr/include/boost/function/function_template.hpp:313 #3 0xb443889d in ~function (this=0xa1a03fc) at /usr/include/boost/function/function_base.hpp:92 #4 0x81a34c39 in ~holder (this=0xa1a03f8) at /home/david/apps/boost_1_34_1/include/boost-1_34_1/boost/any.hpp:106 #5 0x81137b41 in boost::signals::detail::named_slot_map::insert () from /home/david/apps/boost_1_34_1/lib/libboost_signals-gcc41-1_34_1.so.1.34. 1 #6 0x8113b562 in boost::signals::detail::signal_base_impl::connect_slot () from /home/david/apps/boost_1_34_1/lib/libboost_signals-gcc41-1_34_1.so.1.34. 1 #7 0x81a36e58 in boost::signal0<void, boost::last_value<void>, int, std::less<i nt>, boost::function<void ()(), std::allocator<void> > >::connect ( this=0x82eac060, in_slot=@0xbfe145f0, at=boost::signals::at_back) ---Type <return> to continue, or q <return> to quit---bt at /home/david/apps/boost_1_34_1/include/boost-1_34_1/boost/signals/signal_template.hpp:286 #8 0x81b359f6 in fpCTPart::initPart (this=0x82eaa7f0) at /home/david/eclipseM6/toolManagement/extensions/fpCTToolPack/parts/src/fpCTPart.cpp:173 </backtrace> Line 173 in fpCTPart.cpp is: geomNode->sigPreLoad.connect(boost::bind(&fpCTPart::slotFilePreLoaded, this)); Are there any changes between these to versions in the bind/signal library? (Are they not backward compatible?) Thanks in advance. Regards, David

1 0

[ptr_map]iterator::reference is not a reference
by Bill Buklis 11 Oct '07

11 Oct '07

I found what seems to be an inconsistency in ptr_map in version 1.34.1 versus 1.33.1. The "reference" typedef in 1.34.1 does not appear to be a reference. The following code illustrates what I mean: typedef std::map<int, int> STDMAP; typedef boost::ptr_map<int, int> PTRMAP; bool isrefstdmap = boost::is_reference<STDMAP::iterator::reference>::value; bool isrefstdbase = boost::is_reference<STDMAP::reference>::value; bool isrefptrmap = boost::is_reference<PTRMAP::iterator::reference>::value; bool isrefptrbase = boost::is_reference<PTRMAP::reference>::value; In version 1.33.1 all bool values equate to true, while in 1.34.1 ptr_map evaluates to false. In case the compiler makes a difference, I'm using VC++ 2005. -- Bill Buklis --

1 0

[boost][range] fusion::begin and boost::begin dont play nice
by John Femiani 11 Oct '07

11 Oct '07

I am using g++ (GCC) 3.4.2 (mingw-special) and when I use the namespace boost::fusion it causes boost range to break. Consider the toy program 'main.cpp', which is attached and also listed below: ----------------------------------------------------------------------- #include <iostream> using namespace std; #include <boost/fusion/sequence/container/vector.hpp> #include <boost/range.hpp> #include <list> int main() { using namespace boost::fusion; using namespace boost; std::list<int> ints; typedef boost::range_iterator<std::list<int> >::type iterator_t; for (iterator_t i = begin(ints); i != end(ints); ++i){ cout << * i << endl; } return 0; } -------------------------------------------------------------------- This program fails to compile with many errors, the first is C:/MSYS/1.0/include/boost/fusion/sequence/intrinsic/begin.hpp:56: error: invalid use of undefined type `struct boost::fusion::extension::begin_impl<boost::fusion::non_fusion_tag>::app ly<const std::list<int, std::allocator<int> > >' If I remove 'using namespace boost::fusion' then everything compiles. This toy program demonstrates an error I got when trying to compile a function that involved both a fusion::vector and std::list. It was easy to work around it in my case by explicitly saying boost::fusion::begin instead of using the namespace, but I suspect that this is still a bug. Please let me know if I misunderstood the correct way to use fusion or range. Thanx, -- John

3 5

Assigning a var() to another var() in a lambda function
by Peter Waller 11 Oct '07

11 Oct '07

Why does this not compile? Should it? It seems quite similar to code found in the section `Naming delayed constants and variables' in the manual at http://www.boost.org/doc/html/lambda/le_in_details.html #include <lambda/lambda.hpp> using namespace boost::lambda; float i = 5, j = 0; var_type<float>::type vi(var(i)), vj(var(j)); #line 172 (vi = vj); The error I get: /usr/include/boost/lambda/detail/lambda_functor_base.hpp: In member function 'boost::lambda::identity<Float_t&>& boost::lambda::identity<Float_t&>::operator=(const boost::lambda::identity<Float_t&>&)': /usr/include/boost/lambda/detail/lambda_functor_base.hpp:23: error: non-static reference member 'Float_t& boost::lambda::identity<Float_t&>::elem', can't use default assignment operator /usr/include/boost/lambda/detail/lambda_functors.hpp: In member function 'boost::lambda::lambda_functor<boost::lambda::identity<Float_t&> >& boost::lambda::lambda_functor<boost::lambda::identity<Float_t&> >::operator=(const boost::lambda::lambda_functor<boost::lambda::identity<Float_t&> >&)': /usr/include/boost/lambda/detail/lambda_functors.hpp:113: note: synthesized method 'boost::lambda::identity<Float_t&>& boost::lambda::identity<Float_t&>::operator=(const boost::lambda::identity<Float_t&>&)' first required here zzNtuple.C: In function 'int main(int, char**)': zzNtuple.C:173: note: synthesized method 'boost::lambda::lambda_functor<boost::lambda::identity<Float_t&> >& boost::lambda::lambda_functor<boost::lambda::identity<Float_t&> >::operator=(const boost::lambda::lambda_functor<boost::lambda::identity<Float_t&> >&)' first required here make: *** [zzNtuple] Error 1 g++ (GCC) 4.1.2 boost 1.34.1 Thanks in advance, - Peter

1 0

Boost 1.35?
by Matt Wharton 11 Oct '07

11 Oct '07

Hello, Does anyone have a _rough_ timetable for when boost version 1.35 will be formally released? Apologies in advance if this question has already been answered or if this is the wrong venue for it. Thanks, -Matt

2 1

Re: [Boost-users] Boost Spirit and C++/CLI
by Hansi Hansi 10 Oct '07

10 Oct '07

What is exactly the error? Which project type you have? What is your entrypoint? Best regards Hansjörg __________________________________________________________________________ Erweitern Sie FreeMail zu einem noch leistungsstärkeren E-Mail-Postfach! Mehr Infos unter http://produkte.web.de/club/?mc=021131

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