gmane.comp.lib.boost.user

transform_view: question about boilerplate code

Zeljko Vrba — 2008-08-21T17:21:49

I have succeeded in writing the following transform functor: typedef bf::map, bf::pair > Map; typedef bf::vector Pair; struct Map2Pair { template struct result; template struct result : remove_reference { }; template typename T::second_type operator()(T t) const { return t.second; } }; I have tested it, it works. The result magic has been copied from the transform_view example in the documentation and adjusted for the proper return type. Where can I read a bit more about result conventions? In particular, how does the template struct result : remove_reference { }; specialization work when Map2Pair is a struct, and it doesn't even have a constructor! Even worse, why does it work at all when T is not in the scope of the template (.. because it's never used?) Yes, it is

Re: Serialization of derived classes with boost 1.34.1

Robert Ramey — 2008-08-21T17:08:07

Probably something else needs to be explicitly instantiated. Perhaps template void A::serialize(boost::archive::polymorphic_iarchive& ar, const unsigned int file_version); template void A::serialize(boost::archive::polymorphic_oarchive& ar, const unsigned int file_version); Look at the demos. One of them addresses this problem - though not through shared_ptr. Robert Ramey Hansi wrote: _______________________________________________ Boost-users mailing list Boost-users< at >lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

Re: how to make fusion::pair less-than-comparable?

Zeljko Vrba — 2008-08-21T15:56:23

Hmm, an inverted email: first rationale, then conclusion. I asked whether typedef map, pair > Map1; typedef map, pair > Map2; were different because either way makes sense, depending on whether you view the template list as an unordered set or as an ordered list. My "intuition", coming from the run-time case of std::map would lead me to believe that types Map1 and Map2 were the same. Namely, std::map is an unordered set of (K,V) pairs. So, { (a, 1), (b, 2), (c, 3) } and { (c, 3), (a, 1), (b, 2) } have different layout, but for the purpose of asking "which number the letter 'a' is mapped to", they are the same mapping. This coincides with the mathematical definition of function equality: f1 == f2 if domain(f1) == domain(f2), codomain(f1) == codomain(f2), and pointwise equality, f1(x) == f2(x) for each x from the domain. Mathematicians also sometimes say map instead of function: http://mathworld.wolfram.com/Map.html In the light

Wrapping a library

Alan Baljeu — 2008-08-21T13:10:41

I have this library (one class with 700 methods) I want to wrap all the calls, so I can log the calls and do other stuff. Using emacs macros and stuff, I can create a proxy class which has the same signature, but each method calls a C macro which calls the original class method, and does other stuff. For example: void logfunc(char *func) const { OutputDebugStringA(func); } void logarg(int a) // overload for each type of parameter { CString x; x.Format(L"%d", a); OutputDebugString(x); } ULONG GetID(const CKSEntity &pEntity) const { return proxy1(GetID, pEntity); } // repeat for all 700 methods. // Repeat these macros for every count of arg between 0 and 24. #define proxy10(Func, Arg1,Arg2,Arg3,Arg4,Arg5,Arg6,Arg7,Arg8,Arg9,Arg10) \ ( log10(#Func, Arg1,Arg2,Arg3,Arg4,Arg5,Arg6,Arg7,Arg8,Arg9,Arg10), \ thePart.Func( Arg1,Arg2,Arg3,Arg4,Arg5,Arg6,Arg7,Arg8,Arg9,Arg10)) #define log10(Func, Arg1,Arg2,Arg3,Arg4,Arg5,Arg6,Arg7,Arg8,Arg9,Arg10) \ log9(Func

Sample code for boost::thread - Timed Lockable mutex ?

Stéphane Vandenbogaerde — 2008-08-21T15:09:38

Hello, I want to use timed lockable mutex in boost::thread, but the usage is not so obvious for a beginner. Would there be anywhere a sample code with this kind og mutex ? I have a code which works with a boost::mutex in a consumer/producer queue (code below). The purpose is to have a maximum waiting delay for waitForNotEmpty(). Thanks. ------------------------------------------------------------------------- template class MTBornedQueue { public: .... bool waitForNotEmpty() { if (!m_container.empty()) return true; boost::mutex::scoped_lock lock(m_accessMutex); m_notEmpty.wait(lock, boost::bind(&MTBornedQueue::isNotEmpty, this)); return true; } ... private: bool isNotEmpty() const { return m_unread > 0; }; size_type m_unread; container_type m_container; boost::mutex m_accessMutex; boost::condition m_notEmpty; }

[shared_ptr] Implicit cast shared_ptr toshared_ptr

Ruediger Berlich — 2008-08-21T12:47:07

Hi there, after making what I then thought was a bad mistake, I discovered that the code below actually works (gcc 4.3.1, OpenSUSE 11 64bit, Boost 1.36). I.e., there is an implicit cast from shared_ptr to shared_ptr to make it fit the function argument, although both represent different types. Is this intended behaviour (i.e. portable) ? I did not find a corresponding description in the docu. Thanks and Best Regards, Ruediger /**************************************************************************/ #include #include class base{ public: virtual ~base(){} virtual void print() const { std::cout << "Hello world from base" << std::endl; } }; class derived :public base { public: void print() const { std::cout << "Hello world from derived" << std::endl; } }; void executeBasePrint(const boost::shared_ptr& base_ptr){ base_ptr->print(); } main(){ boost::shared_ptr derived_ptr(new derived()); // Results in "Hello worl

Re: [filesystem] Bugs in path::append ?

Sachin Garg — 2008-08-21T15:37:46

Yes, the 'uncomplete' you suggest would be a much cleaner way. IMHO advance() would be needed just to complete the iterator implementation. Yes, 7 was just suggested as an example here. It comes from counting the number of elements in input_base_path. The use case here is creating complete output paths for "copy-pasting a sub-tree from input_base_path to output_base_path" (ofcourse with some transformations along the way). For now, I am using fs::wpath output_path=output_base_path; int k=0; for(fs::wpath::iterator i=input_path.begin();i!=input_path.end();i++,k++) if(k>=7) output_path/=(*i); Again, 7 is the number of elements in input_base_path. advance() would make it atleast slightly cleaner (remove k, and the if on k), uncomplete would be ideal. Sachin Garg

Re: Fusion: some concrete questions about maps andvectors

Joel de Guzman — 2008-08-21T14:44:00

Yes. Yes: transform_view. It won't be a fusion vector, but the effect is what you want. Sounds good. One step at a time. Tell us if you need some help/advice on various issues. Regards,

Re: how to make fusion::pair less-than-comparable?

Joel de Guzman — 2008-08-21T14:35:22

The reason is I don't know (yet) how to do 1 :-) If there are some suggestions, I see no reason why it can't be added to the library. So... how do you compare a half-static-half-runtime pair? Compare just the value part? How about pairs with different static parts but comparable runtime parts, how do they compare? Simply disallow? Comments, suggestions welcome. Regards,

Re: Serialization of derived classes with boost 1.34.1

Tim St. Clair — 2008-08-21T14:32:12

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how to make fusion::pair less-than-comparable?

Zeljko Vrba — 2008-08-21T14:27:35

Related to my previous question: fusion::map is a sequence and instances of it could be directly compared with operator < , thus vectors of instances also sorted if fusion::pair supported relational operators other than == and != (which it doesn't). So, two questions: 1. What is the recommended way of defining operator< for particular pair instances (e.g. for pair) ? 2. An explanation of why doesn't fusion::pair define at least operator< would be welcome. Thanks. (Yes, I know, I can pass an explicit predicate to std::sort.. )

Re: boost::graph issues.

Robert Jones — 2008-08-21T12:51:12

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Re: [filesystem] Bugs in path::append ?

Scott McMurray — 2008-08-21T12:30:48

I suspect it's simply that it wasn't included in the TR proposal, wanting to leave open different options for implementations. I have a feature request for an "uncomplete" function in; Would you be happy with something like this instead? complete( uncomplete(i, input_base_path), output_path); Where input_base_path would be the first 7 components of your input_path. (I'm guessing that the 7 comes from some other path, rather than being hard-coded somehow.) Hoping to find a new use case, ~ Scott

Re: cross-platfrom binary serialization?

Pfligersdorffer, Christian — 2008-08-21T11:42:15

Hi Roman and Akos! boost-users-bounces< at >lists.boost.org on : And gcc-4, which also supports the #pragma once. The use of this construct and the warnings is simply a result from my strive to minimalize code length. What I express in code is the algorithmical idea in the shortest possible way I can think of. Let the compiler complain about it, I don't care because I _know_ what I'm doing and the warnings are vain. They issue from using one metafunction for all integral types, be them signed or unsigned. Of course you could separate those but only by introducing verboseness. Originally I even let the integral function treat the bool case resulting in even more warnings. The zero bool tweak in mind I decided to write an extra overload for bool. However if you have suggestions that fix the warnings and come close to a minimal solution I'll be happy to look into it. I include enough boost headers which implicitly include version.hpp and the like so I need not bother making this explicit. We do. Using the arch

Re: AIX 5.3 xlC error on ptr_list.hpp

Markus Schöpflin — 2008-08-21T11:33:59

[...] The trunk is tested against XL C/C++ V9.0.0.3, see http://beta.boost.org/development/tests/trunk/developer/summary.html for reference. The release branch is not tested for this compiler, but I don't see any specific reason why the results should differ much from the current trunk results. Especially http://beta.boost.org/development/tests/trunk/developer/ptr_container.html shows that at least ptr_list should work with this compiler. Which version of the compiler are you using? You probably need to update your compiler. HTH, Markus

Fusion: some concrete questions about maps and vectors

Zeljko Vrba — 2008-08-21T11:16:44

I'm operating on two vectors of pairs of numbers, currently represented by std::pair. The first vector is a list of (net,pin) pairs, while the second vector is a list of (pin, net) pairs. In order to raise a bit the understandability / abstraction level of my code, I think that it'd be nice to be able to write at_key(x) and at_key(x) instead of x.first or using tie(). Looking at fusion manual, it seems that of all the containers, map suits the purpose: struct pin; struct net; First question: are Map1 and Map2 different types? typedef map, pair > Map1; typedef map, pair > Map2; According to a simple test program that I wrote, which basically boils down to Map m1; Map m2; m1 = m2; they, are different because the compilation fails. Hmm, so far, so good. Second question: some algorithms are common both for both types, e.g. sort, where I want to have lexicographical comparison between the elements. Is it

Compiling with a different version of a compiler

Sean Farrow — 2008-08-21T11:16:39

Hi: Is there a way of compiling with a different version of a compiler. I.e specifying a path on the command line or two command-line in the .jam file. Chers Sean. __________ Information from ESET NOD32 Antivirus, version of virus signature database 3374 (20080821) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com

Re: AIX 5.3 xlC error on ptr_list.hpp

Thorsten Ottosen — 2008-08-21T10:56:48

Gary Fu skrev: Well, I don't think AIX x1C was one of the officially supported compilers for 1.36, was it? Maybe it's time to complain to your compiler vendor that it does not compile some of the Boost libraries ... -Thorsten

Re: How to find a sorting permutation

Mike Marchywka — 2008-08-21T10:49:28

If you haven't looked already, I would always suggest citeseer if for nothing else than benchmarks and tests of whatever you decide to do. A quick naive keyword search is as follows, http://citeseerx.ist.psu.edu/search?q=sort+permutation+order&sort=rel I think all of the papers are available free full text. _________________________________________________________________ Get ideas on sharing photos from people like you. Find new ways to share. http://www.windowslive.com/explore/photogallery/posts?ocid=TXT_TAGLM_WL_Photo_Gallery_082008

Re: Implementation question aboutboost::circular_buffer and allocator

Peter Barker — 2008-08-21T10:02:30

--- On Wed, 20/8/08, Daryle Walker hotmail.com> wrote: Daryle, Thank you very much - That was driving me crazy!

Serialization of derived classes with boost 1.34.1

Hansi — 2008-08-21T10:01:44

Hello, I have a problem to serialize a derived class. In some classes I use a shared_ptr which acts as a interface for some other classes. Til now I had the implementation in the header and it worked fine with the BOOST_CLASS_EXPORT(B) declaration after at the end of the header file where B was defined. For performance reason (compile time) I have moved the serialization code from the header file (there is only the declaration) to the .cpp file (now I use also only the polymorphic_binary_archive). There I have also the declaration for the polymorphic_binary_archive template void B::serialize(boost::archive::polymorphic_iarchive& ar, const unsigned int file_version); template void B::serialize(boost::archive::polymorphic_oarchive& ar, const unsigned int file_version); After linking I have now some linker errors. First for the class B which is derived from A and for the class A. All linker errors use the binary_archive. If I declare the "BOOST_CLASS_EXPORT(B)" at the end in the .cpp file I g