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[boost.iostreams] using zlib with wide streams
by Sean Farrow 16 Feb '12

16 Feb '12

Hi: Is is possible ot use zlib/bzip2 with wide streams. Any help appreciated. Cheers Sean.

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Re: [Boost-users] Developing a new boost archive
by Roberto Fichera 16 Feb '12

16 Feb '12

Actually I cannot really answer because I haven't had yet a deeper look at the suggest "export" method details. Neverthelss, what I need is an explicit string because certain format might require such information used to instantiate objects of the given class while deserializing in other languages (java or python for example). But also pure text formats optionally provide this information with the purpose of helping the user to understand/verify the content of the result of the serialization. My library, which is written in pure C code for compatibility reasons, does solves easily the problem by stringify the given type via pretty straight macro inside the serialization function itself. Something like opening a type, serialize all the fields and close the type. The use of the macro obviously doesn't work at all when using it under any template declaration because the preprocessor is called earlier in compilation process. I also tried the parsing of the __PRETTY__FUNCTION__ which works perfectly under template function, but this approach is even more un-portable then the demangler, so not really praticable. Sent from my ASUS Eee Pad Larry Evans <cppljevans(a)suddenlink.net> wrote: >On 02/15/12 12:38, Robert Ramey wrote: >> Roberto Fichera wrote: >>> On 02/15/2012 06:01 PM, Robert Ramey wrote: >> >>>> c) Even worse, the aproach above would make even text archives >>>> non-portable between platforms. Of course this is a non-starter. >>>> So you might want to re-think your approach above. >>> >>> I agree totally with you! Actually my constraint is to use gnu >>> toolchain, >>> MSVC and pathscale compilers and eventually LLVM, but this one is not >>> a priority at moment. But, any way still the problem of the demangling >>> portability. >>> >>> By the way, how did you solve the problem ... if you solved it, >>> indeed ;-) ? >> >> It is already solved portably via the "export" functionality. Look >> it up in the documentation. >> >> Robert Ramey >Hi Robert, > >Looking at: > > http://www.boost.org/doc/libs/1_48_0/libs/serialization/doc/serialization.h… > >and reading: > > The system "registers" each class in an archive the first time an > object of that class it is serialized and assigns a sequential > number to it. Next time an object of that class is serialized in > that same archive, this number is written in the archive. So every > class is identified uniquely within the archive. When the archive > is read back in, each new sequence number is re-associated with the > class being read. Note that this implies that "registration" has to > occur during both save and load so that the class-integer table > built on load is identical to the class-integer table built on > save. In fact, the key to whole serialization system is that things > are always saved and loaded in the same sequence. This includes > "registration". > >And paraphrasing part as: > > So every class is identified by this uniquely assigned sequential > number within the archive. > >Then I'd infer that this "uniquely assigned sequential number" play >a role similar to the role of the result of: > > abi::__cxa_demangle( typeid( T ).name(), 0, 0, NULL ); > >in Roberto's post: > > http://article.gmane.org/gmane.comp.lib.boost.user/72805 > >As you mention, Roberto's method is not portable between platforms >(where, of course, a different compiler or even different version >of the same compiler would be a different platform). > >OTOH, as you also mention in the above quote, boost serialization >requires: > > things are always saved and loaded in the same sequence. > >Roberto, would that be a problem for you? > >-regards, >Larry > > > > > >_______________________________________________ >Boost-users mailing list >Boost-users(a)lists.boost.org >http://lists.boost.org/mailman/listinfo.cgi/boost-users

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[Program_options] How to parse a command-line incrementally
by Olaf Meeuwissen 16 Feb '12

16 Feb '12

Hi all, I'm looking to implement an "incremental" command-line parser using Boost.Program_options. The parser should be incremental in the sense that parsing should stop at the first unknown option or positional argument. At this point, my program would pick the next options description and continue parsing with that. This would proceed until the command-line has been parsed completely or the program is no longer interested in the remainder. The idea is to use this for a program that interfaces to a collection of commands that each support a set of actions. The program, commands and actions all have their own list of options, so you get command-lines like so prog [prog-opts] [cmd [cmd-opts] [act [act-opts]]] Eventually, I might want to throw in positional arguments for some or each of these as well. Any suggestions on how to achieve this? My main concerns are with the way Boost.Program_options wants to parse the whole command-line (when using allow_unregistered()) every time and with how to keep track of what still needs to be processed. Thanks in advance, -- Olaf Meeuwissen, LPIC-2 FLOSS Engineer -- AVASYS CORPORATION FSF Associate Member #1962 Help support software freedom http://www.fsf.org/jf?referrer=1962

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Boost Phoenix Arguments Passing & Storage (-- Proper Type?) & Application to RValues -- Possible?
by Matt 15 Feb '12

15 Feb '12

Hi there! I've got a question (two, in fact) regarding Arguments in Boost Phoenix. Assuming using boost::phoenix::arg_names::arg1; using boost::phoenix::val; using boost::phoenix::ref; using boost::phoenix::cref; Why does this compile (and works): int x = 1; int y = 2; std::cout << (arg1 % 2 == 1)(x) << '\n'; std::cout << (arg1 % 2 == 1)(y) << '\n'; while these fail to compile (with an extremely long diagnostic involving "boost::error_cant_deduce_type"): std::cout << (arg1 % 2 == 1)(1) << '\n'; std::cout << (arg1 % 2 == 1)(2) << '\n'; std::cout << (arg1 % 2 == 1)(val(1)) << '\n'; std::cout << (arg1 % 2 == 1)(val(2)) << '\n'; std::cout << (arg1 % 2 == 1)(cref(1)) << '\n'; std::cout << (arg1 % 2 == 1)(cref(2)) << '\n'; I run into this was while attempting to store an Arg. into a variable, i.e.,: auto f = (arg1 % 2 == 1); this works: std::cout << f(x) << '\n'; std::cout << f(y) << '\n'; while this fails: std::cout << f(1) << '\n'; std::cout << f(2) << '\n'; I'm guessing this must be for the same reason the above attempts fail. Another question is, what's the "proper" type of "f" assuming non-C++11 compiler? I'd like to avoid wrappers like boost::function (assuming that's even possible). Later on, I'd like to return such an "f" from a function, hence the question (in C++11 I can get away with decltype for short and easy ones, i.e., prototypes like this "auto newActor() -> decltype((arg1 % 2 == 1))" work, but this becomes inconvenient for longer bodies). A concoction like this compiles but doesn't produce an output: auto f = (val(arg1) % 2 == 1); std::cout << f(val(0)) << '\n'; // and I'm guessing this is very wrong anyway due to unusual behavior. Best, Matt

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Developing a new boost archive
by Roberto Fichera 15 Feb '12

15 Feb '12

Hi All in the list, I'm basically new to boost so I hope to find support here to integrate my own serialization library within the boost archive logic. I would say as premise that I started to have a look in all the boost archive implementation so binary, xml and text trying to understand the logic but that increased my confusion about how to approach the solution of my problem. Confusion that is increased by the lack of my boost knowledge and it's related template programming, of course. By the way I found really instructive the simple_log_archive example that cleanly shows how to "walk" the full tree of the data representation in terms of serialization chain. Furthermore, I would say that my serialization framework does already handle all the representation formats like binary, xml, text, python and many others, so from the boost archive point of view I need just to know very few things: - how to walk the tree representing the serialization chain - how to detect that a new type is being serialized - how to get the type name as string - how to define primitive types - how to manage vectors/arrays - be sure that everything is passed as nvp About the two first, they seems related because the code below seems responsible to walk the tree and call all the serialize functions template< class Archive > struct save_only { template< class T > static void invoke( Archive & ar, const T & t ) { // make sure call is routed through the highest interface that might // be specialized by the user. boost::serialization::serialize_adl( ar, const_cast< T & >( t ), boost::serialization::version< T >::value ); } }; So I've put my two functions that are used to defines types: myserialize_beginType( myserialize &s, char *fieldName, char *type ) myserialize_endType( myserialize &s ) Such as the serialization walk chain looks like: template< class Archive > struct save_only { template< class T > static void invoke( Archive & ar, const T & t ) { // make sure call is routed through the highest interface that might // be specialized by the user. -->> myserialize_beginType( ar.serializer, ar.fieldName, ???type??? ); boost::serialization::serialize_adl( ar, const_cast< T & >( t ), boost::serialization::version< T >::value ); -->> myserialize_endType( ar.serializer ); } }; But actually I don't know how to determine the type name as string to pass to my beginType function. About the place to define primitives, I'm not really sure if it's the right place where I have to put my serialization primitives that maps all my basics types. The prototype of such overloaded function is like myserialize_serialize( "basetype" &t, char * fieldName, myserialize &s ) Actually I've defined something like: #define BOOSTSERIALIZEARCHIVE_PRIMITIVE( __T ) \ simple_log_archive & operator<<( const boost::serialization::nvp< __T > & t )\ {\ myserialize_serialize( t.value(), (char*)t.name(), this->serializer );\ return *this;\ } BOOSTSERIALIZEARCHIVE_PRIMITIVE( char ) BOOSTSERIALIZEARCHIVE_PRIMITIVE( unsigned char ) which seems to work. About managing vectors and array, actually I tried to define something like: template< class Archive > struct use_array_optimization { template < class T > static void invoke( Archive & ar, const T & t ) { myserialize_serialize( (T*)t.address(), ar.fieldName , t.count() * sizeof( T ), ar.serializer ); } }; template< class T > void save( const T &t ) { typedef BOOST_DEDUCED_TYPENAME boost::mpl::eval_if<boost::is_enum< T >, boost::mpl::identity<save_enum_type<simple_log_archive> >, // else -->> BOOST_DEDUCED_TYPENAME boost::mpl::eval_if<boost::is_array< T >, -->> boost::mpl::identity<use_array_optimization<simple_log_archive> >, //else BOOST_DEDUCED_TYPENAME boost::mpl::eval_if< // if it's primitive boost::mpl::equal_to< boost::serialization::implementation_level< T >, boost::mpl::int_<boost::serialization::primitive_type> >, boost::mpl::identity<save_primitive<simple_log_archive> >, // else boost::mpl::identity<save_only<simple_log_archive> > > > >::type typex; typex::invoke( *this, t ); } but this seems not working at all. Finally the last items, be sure that everything is passed as nvp in order to catch each given field name, I simply don't know how to do this check/constraint. Hopefully to get some support. Thanks in advance, Roberto Fichera.

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Dependency Issue
by Guruswamy B M 15 Feb '12

15 Feb '12

Hi, I am using boost python for one of my application. It works fine in a machine where visual studio installed. If visual studio removed then app will through a error ""ImportError: DLL load failed: This application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem.". I have searched through internet, but I am not able find a proper solution for this. However i have installed 2008 visual studio redistribution package. Also I resolved dependency problem which is shown by dependency walker. Any help regarding this issue greatly appreciated. Thanks, Guru

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[range] count vs count_if
by Bill Buklis 15 Feb '12

15 Feb '12

The documentation for boost range states that count_if can be expressed as count using a filtered adaptor and then goes on to say that no algorithm needs the _if suffix. I'm having trouble seeing how that is the case. Here is the relevant section from the latest (1.49 beta) documentation <http://www.boost.org/doc/libs/1_49_0_beta1/libs/range/doc/html/range/refere…>. Range Adaptor alternative to count_if algorithm <http://www.boost.org/doc/libs/1_49_0_beta1/libs/range/doc/html/range/refere…> boost::count_if( rng, pred ); can be expressed as boost::count( rng | boost::adaptors::filtered(pred), out ); What this means is that /*no*/ algorithm with the |_if| suffix is needed. First of all, what is "out"? I think this is supposed to be "value" as count requires the value to compare against for the count. But, since it does require the value, this makes the function fundamentally different than count_if which will only count the values that match the predicate. As far as I can tell, this means that "count" will filter values both by the predicate and by the value. What am I missing? How can count_if be properly expressed as count. To me it seems like it can't. -- Bill

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MSVC static linking with Boost
by Andy Falanga (afalanga) 14 Feb '12

14 Feb '12

Hi, The team I work with is working on producing a Boost.Python library. Most of the Boost stuff we're using are header only, however, there is a couple of compiled library usages as well (e.g. regex). How can we make certain that the library we're building is statically linked with the stuff we're using from Boost? This way, we don't have to deploy any other DLLs but our own. I've gathered, from Google and another post here, that most of this magic happens at compile time with auto-linking. However, this isn't going all the way. I continually see Intellisense errors in my Visual Studio output window telling me that mixing static and dynamic Boost libraries is a bad idea (or something similar). So, for Visual Studio 2010, how do I ensure that the libraries are statically linked into our own product? Thanks, Andy

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BoostCon/C++Now! Talk: How I Code and Why
by Gottlob Frege 14 Feb '12

14 Feb '12

I talked about this last year, and this year I've submitted the proposal, so If you volunteered last year (and are still interested) and/or are interested in helping with a particular/peculiar talk at BoostCon/C++Now this year, then read on, and contact me offline: I'm planning on giving a talk, entitled "How I Code and Why". It is not meant to be presumptuous and tell you how *you* should code, but instead just explains how I code - day-to-day - and how I came to these patterns/conclusions. But who cares just about how *I* code, people want to hear how other members of the Boost community - people they've come to know and respect via the boost lists - code. So I'm hoping to have a few co-conspirators on stage with me, and have each explain a fundamental guiding principle that they follow in their every day code, how they came to adopt this principle and why they find it valuable. For example, I will tell the simple story ('epiphany') of why my favourite comment word is 'otherwise', and how this relates to advice you may have heard or read before. I like the flavour of [ simple, real world, specific ] ---> [ general principle ] The goal is to bring a more real world down to earth picture to the sometimes lofty fundamentals found in books and lectures. Instead of a book explaining how a guiding principle makes sense *in theory*, it would be great (I think) to hear how respected members of the community apply these principles in real life. So, if you want to participate, email me, and we will see what we can figure out. (And/or I might just have to track you down based on promises made last year!) Not sure how many people we need. I'm thinking 5-15 mins per 'principle', and I think you only need to present one (I think the weight of picking *just one* principle makes it all the more interesting). Anyhow, we can work out the details as we go along. Tony PS. this is not (yet?!) an accepted talk, but I have a bit of chicken/egg thing here: ie it would help to have a few people on board to show that the talk is viable, and thus be accepted.

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A plea for simpler tools
by Robert Ramey 14 Feb '12

14 Feb '12

Let me start by saying I love Boost and C++ as much or more than anyone here!!! But I'm really frustrated with the boost tools and believe they are a serious impediment to the progress of boost. Here is what I want to be able to do: a) create a directory structure outside of the boost tree which looks like: mylib build include src doc html docbook(maybe) boostbook(maybe) quickbook(maybe) test results ... b) a set of simple tools which 1) can build the library in the src directory 2) can translate quick/boost/doc book to html and place it in that directory 3) run each test in the test directory and add a record to the test/results/... log file which I will either just lookat or post process locally to my personal taste. c) what I don't need 1) tracking dependencies - I want to do this for on library I might be experimenting with. I can do this by hand. 2) I don't need to have my boost tree updated - in fact I want to know that I haven't changed it by just running a simple tool d) current tools: 1) presume that a library is part of the boost directory structure. So the documents show up somewhere in the boost tree. Note when I build the documents on my local boost release image I get pointers to the boost sandbox or on sourceforge.net or whatever. So for boostbook->html would like to be able to say boostbook2html -in <boostbookdir> -out <htmldirectory> or something simple like this. 2) the only way I've found to use the current tools is to create directories in my local boost release tree with my "experimental" library and run bjam. There are two problems with this i) I have to make a jamfile which might be more complicated that first meets the eye ii) I mucks up my boost release tree. iii) it I get something wrong, it fails deep within some bjam script which is extremely difficult to figure out. iv) For an example to iii) above, I had tweaked userconfig.v2 to include the name of my xsltproc program which was found through the path. Later I elimnated the directory of the xsltproc from my path. Later I found I couldn't build my library or run any tests. Turned out that bjam stopped when it failed to find the xsltproc program - even though it wasn't being used. I'm not critisizing bjam. I think it's impossible to make a program as ambituous as this totally perfect. But I question the need for such an elaborate tool for doing what seems to me should be something simple. Of course, I can do this myself - and likely will end up doing so. But: a) I've got other stuff to do b) I can't believe I'm the only one who needs this c) I think that boost tools are "too automatic" for my purposes. I understand the motivation for building all of boost. But for what I want to do it adds a huge layer of "conceptual overhead" that I have to wade through. Before I invest effort in this perhaps there's a way of using existing tools that I'm not aware that get's me closer to what I want and need. Comments welcome. Robert Ramey

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