September 2008 - Boost-users - lists.preview.boost.org

Re: [Boost-users] [review] Dataflow Review starts today, September 1st
by Maarten Nieber 02 Sep '08

02 Sep '08

Hi, in the last year, I have been doing a lot of dataflow programming so potentially I am very interested in this library. However, I would really like to see a documentation page that "sells" the library. I would like to see a description of cases that would be difficult, timeconsuming or hard to adapt for future requirements when implemented without this library, and understand how the library makes life easier. Instead, the library documentation quickly focuses on the architecture, i.e. the different layers in the library. There are some examples (VTK, graphical editor), but from these too I cannot tell if this library would help me or not. Best regards, Maarten ----- Original Message ---- From: Jaakko Järvi <jarvi(a)cs.tamu.edu> To: boost-users <boost-users(a)lists.boost.org> Sent: Monday, September 1, 2008 4:00:49 PM Subject: [Boost-users] [review] Dataflow Review starts today, September 1st The review of Stjepan Rajko's Dataflow library starts today, September 1st, and will run until September 10th. --------------------------------------------------------- Description of the library: Dataflow is a generic library for dataflow programming. Dataflow programs can typically be expressed as a graph in which vertices represent components that process data, and edges represent the flow of data between the components. As such, dataflow programs can be easily reconfigured by changing the components and/or the connections. This review focuses on the Dataflow.Signals layer of the library. For its data transport mechanism, Dataflow.Signals uses Boost.Signals which can be used to make lasting dataflow connections based on function calls. Dataflow.Signals provides the following to facilitate signals-based dataflow networks: * A number of useful general-purpose components, and building blocks for implementing new components. * Various free functions and operators for connecting and using components. The library documentation provides some concrete examples of how Dataflow.Signals layer can be used. Some examples are: * Implementing distributed dataflow applications using Dataflow.Signals and Boost.Asio * An image processing network using Dataflow.Signals and Boost.GIL * A GUI dataflow editor (located in the Dataflow.Blueprint documentation) While the Dataflow library contains other layers, only the Dataflow.Signals layer is ready for review. Reviewers are welcome to provide feedback for any part of the library, but please be aware that the documentation and implementation for the other layers may be lacking (for example, there is the generic support layer, which provides concepts applicable to different dataflow frameworks, and can be used to develop generic dataflow code, as well as the Dataflow.Blueprint layer which provides run-time reflection and modeling of dataflow networks in a Boost Graph Library graph for any dataflow framework with implemented Dataflow library support). For the time being, please consider these other layers as implementation details or proof-of-concept examples, as appropriate. The library is accessible as a tarball at: http://www.boostpro.com/vault/index.php?&directory=Dataflow The documentation can be accessed here: http://www.dancinghacker.com/code/dataflow/ The documentation particular to the Dataflow.Signals layer under review: http://www.dancinghacker.com/code/dataflow/dataflow/signals.html Dataflow depends on many existing Boost libraries, such as Fusion and MPL. The Dataflow.Signals layer builds functionality over Boost.Signals. The Dataflow library has been tested using a recent version of the Boost trunk, as well as the 1.35 release. Tests and examples have been built successfuly on OS X (GCC 4.0, 4.2), Linux (GCC 4.2), and Windows (MSVC 8.0 and to some degree MinGW GCC 4.2). --------------------------------------------------------- --------------------------------------------------------- Questions you may want to answer in your review: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? In particular, please remember to answer the following question explicitly: - Do you think the library should be accepted as a Boost library? Jaakko Järvi Review Manager _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Re: [Boost-users] [review] Dataflow Review starts today, September 1st
by Manuel Jung 02 Sep '08

02 Sep '08

Jaakko Järvi wrote: > The review of Stjepan Rajko's Dataflow library starts today, September > 1st, and will run until September 10th. > > --------------------------------------------------------- > Description of the library: > > Dataflow is a generic library for dataflow programming. Dataflow > programs can typically be expressed as a graph in which vertices > represent components that process data, and edges represent the flow > of data between the components. As such, dataflow programs can be > easily reconfigured by changing the components and/or the connections. > > This review focuses on the Dataflow.Signals layer of the library. For > its data transport mechanism, Dataflow.Signals uses Boost.Signals > which can be used to make lasting dataflow connections based on > function calls. Dataflow.Signals provides the following to facilitate > signals-based dataflow networks: > > * A number of useful general-purpose components, and building blocks > for implementing new components. > * Various free functions and operators for connecting and using > components. > > The library documentation provides some concrete examples of how > Dataflow.Signals layer can be used. Some examples are: > > * Implementing distributed dataflow applications using > Dataflow.Signals and Boost.Asio > * An image processing network using Dataflow.Signals and Boost.GIL > * A GUI dataflow editor (located in the Dataflow.Blueprint documentation) > > While the Dataflow library contains other layers, only the > Dataflow.Signals layer is ready for review. Reviewers are welcome to > provide feedback for any part of the library, but please be aware that > the documentation and implementation for the other layers may be > lacking (for example, there is the generic support layer, which > provides concepts applicable to different dataflow frameworks, and can > be used to develop generic dataflow code, as well as the > Dataflow.Blueprint layer which provides run-time reflection and > modeling of dataflow networks in a Boost Graph Library graph for any > dataflow framework with implemented Dataflow library support). For > the time being, please consider these other layers as implementation > details or proof-of-concept examples, as appropriate. > > The library is accessible as a tarball at: > http://www.boostpro.com/vault/index.php?&directory=Dataflow > > The documentation can be accessed here: > http://www.dancinghacker.com/code/dataflow/ > > The documentation particular to the Dataflow.Signals layer under review: > http://www.dancinghacker.com/code/dataflow/dataflow/signals.html > > Dataflow depends on many existing Boost libraries, such as Fusion and > MPL. The Dataflow.Signals layer builds functionality over > Boost.Signals. The Dataflow library has been tested using a recent > version of the Boost trunk, as well as the 1.35 release. Tests and > examples have been built successfuly on OS X (GCC 4.0, 4.2), Linux > (GCC 4.2), and Windows (MSVC 8.0 and to some degree MinGW GCC 4.2). > --------------------------------------------------------- > > > --------------------------------------------------------- > Questions you may want to answer in your review: > > - What is your evaluation of the design? > - What is your evaluation of the implementation? > - What is your evaluation of the documentation? > - What is your evaluation of the potential usefulness of the library? > - Did you try to use the library? With what compiler? Did you have any > problems? - How much effort did you put into your evaluation? A glance? A > quick reading? > In-depth study? > - Are you knowledgeable about the problem domain? > > In particular, please remember to answer the following question > explicitly: > > - Do you think the library should be accepted as a Boost library? > > > Jaakko Järvi > Review Manager > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost Hey, The filter of the GIl example is always processed, whether or whether not it is multiplexed to the output, right? Maybe it would be good to insert a conditional component right before the filter, therefore the data is dropped, if the multiplexer takes data from slot 0. Otherwise a senseless computation is done, if the filter is turned off. I wanted to alter the example as suggested, but i don't know how to use the conditional component? I couldn't find a example for that. Maybe you could point out how to use it. Kind Regards Manuel

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Buffers - slices.
by Leandro Lucarella 02 Sep '08

02 Sep '08

Hello. I've been searching for a "buffer" class. I mean, a class like std::string with a .data() method that returns a mutable char* instead of a const char*. So I can do something like: std::string buffer; buffer.reserve(SIZE); int n = recv(fd, buffer.data(), SIZE, 0); I know I probably can do that with a cast anyways, but I don't think it's pretty nor "defined behaviour", right? Another thing sometime I need, is some string processing *without* copying. Something like a readonly substring view. What I think of is basically some struct like: struct slice { const char* ptr; size_t len; } which has all the other (at least no-mutable) operation of a string. Something like doing a std::string::substr() but without the copying. Are there any support for this stuff on boost? Do you know any other libraries which have this? TIA. -- Leandro Lucarella (luca) | Blog colectivo: http://www.mazziblog.com.ar/blog/ ---------------------------------------------------------------------------- GPG Key: 5F5A8D05 (F8CD F9A7 BF00 5431 4145 104C 949E BFB6 5F5A 8D05) ---------------------------------------------------------------------------- You look so tired-unhappy, bring down the government, they don't, they don't speak for us.

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[thread] wrong assertion following call to pthread_mutex_timedlock()?
by Wolfgang Fertsak 02 Sep '08

02 Sep '08

In boost 1.35 and 1.36 the implementation of mutex::timed_lock() and recursive_mutex::timed_lock() for posix-platforms with BOOST_PTHREAD_HAS_TIMEDLOCK defined looks like this: bool timed_lock(system_time const & abs_time) { struct timespec const timeout=detail::get_timespec(abs_time); int const res=pthread_mutex_timedlock(&m,&timeout); BOOST_ASSERT(!res || res==EBUSY); return !res; } The assertion following pthread_mutex_timedlock() always fails in case of a timeout since the system call returns ETIMEDOUT when timed out and not EBUSY (according to the open group specification http://www.opengroup.org/onlinepubs/009695399/functions/pthread_mutex_timed…) Best regards, Wolfgang

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[filesystem][xpressive] Hotfix patches available for 1.36.0
by Beman Dawes 02 Sep '08

02 Sep '08

Hotfix patches are available to fix Boost.Filesystem and Boost.Xpressive [1.36.0] problems. See https://svn.boost.org/trac/boost/wiki/ReleasePractices/HotFixes Providing hotfix patches is something new and experimental for Boost. Please let us know if you find the patches useful or have other comments. Thanks, --Beman

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[statechart] Events not consumed when using derived states?
by Stefan Steuerwald 01 Sep '08

01 Sep '08

Dear statecharters, I would like to request help with a problem building a statemachine from states that I derive from simple_state. Here is minimal code that defines two states StateA and StateB and an event cycling between these two: #include <boost/statechart/state_machine.hpp> #include <boost/statechart/simple_state.hpp> #include <boost/statechart/event.hpp> #include <boost/statechart/transition.hpp> namespace sc = boost::statechart; using namespace std; class StateA; struct StateMachine : sc::state_machine< StateMachine, StateA > { void unconsumed_event( const sc::event_base & evt ) { cout << "unconsumed!" << endl; } }; class Event : public sc::event< Event > {}; struct StateA : sc::simple_state< StateA, StateMachine > { typedef sc::transition< Event, StateB > reactions; }; struct StateB : sc::simple_state< StateB, StateMachine > { typedef sc::transition< Event, StateA > reactions; }; ----------------- This works fine as expected with process_event( Event() ). However, I would like to derive the states of my statechart from a class like this: template<class context> struct State : sc::simple_state< State<context>, context > { // Some application-specific things }; struct StateA : State< StateMachine > { typedef sc::transition< Event, StateB > reactions; }; struct StateB : State< StateMachine > { typedef sc::transition< Event, StateA > reactions; }; ----------------- Now, calling process_event( Event() ) does not do anything, except turning the event up at the StateMachine::unconsumed_event() method. I am aware of this one: http://www.boost.org/doc/libs/1_35_0/libs/statechart/doc/faq.html#Templated… but I'm not sure whether this applies in any way to my case, as I don't have any compiler errors. May I be violating some prerequisites here? Thank you for any help you can provide, Stefan.

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unit test XML ouput to HTML XSL?
by Ákos Maróy 01 Sep '08

01 Sep '08

Hi, I'm wondering if someone has already created an XSL stylesheet that transforms the XML output of boost::test to human-friendly HTML? It would be even better if this XSL could combine the output of several test output XML files. I'm also wondering on the state of integration between boost test and continous integration tools, like Hudson, Bitten, etc.. Thanks, Akos

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Serializing a char *
by Diane 01 Sep '08

01 Sep '08

Based on tutorial and reference material, and some previous posts here, it seems like I should be able to serialize a char* by using a wrapper like tracked_char: BOOST_STRONG_TYPEDEF(char, tracked_char) template<class Archive> void serialize(Archive &ar, tracked_char & tc){ ar & tc; } But when I try to serialize my struct that contains char*: typedef struct MYSTRUCT { char chtest; char *chstar; } MYSTRUCT; template<class Archive> void serialize(Archive & ar, MYSTRUCT & it, const unsigned int version) { ar & it.chtest; tracked_char *tcp = it.chstar; //****error on this line****// ar & *tcp; } I get this compile error: cannot convert `char*' to `tracked_char*' in initialization What is the compiler complaining about here? How do I fix it? I'm not sure if I have the correct usage of BOOST_STRONG_TYPEDEF, so I also tried: struct tracked_char { char m_char; // the real data template<class Archive> void serialize(Archive &ar, unsigned int version){ ar & m_char; } // casting operators - not compiled char operator char () const { //****error here****// return m_char; } char & operator char() { //****error here****// return m_char; } }; I need someone to point me in the right direction. Thanks, Diane

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Changing from std::map to boost::bimap
by Sean Farrow 01 Sep '08

01 Sep '08

Hi: I am looking to change from std::map to boost::bimap. I have the following defined: std::bimap<std::bitset<6>, int, BitSetComp> DotsList; And boost::bimap<std::bitset<6>, int, BitSetComp>::iterator DotsIterator; If it's needed BitsetComp is defined as: struct BitSetComp { bool operator()(const std::bitset<6>& lhs, const std::bitset<6>& rhs) const { return lhs.to_ulong() < rhs.to_ulong(); } }; How do I change these definitions to use boost::bimap. Any help apreciated. Chers Sean. __________ Information from ESET NOD32 Antivirus, version of virus signature database 3401 (20080829) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com

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[Serialization] Are the serialized char* different when code runs in 32/64 bits machines ?
by jotalo jotalo 01 Sep '08

01 Sep '08

Hi, I use the Bost serialization library to serialize some classes that I put in a char* variable ... I have a Server which publish this char* variable and Clients get this variable and de-serialize it to obtain the original class... Everything work fine when servers and clients are running in machines with the same architecture (64 or 32 bits)... But when I run the server in a 64 bits machine, the char* variable is not recognized in a 32 bits client. In this code: std::stringstream is; is.rdbuf()->pubsetbuf(c, m_StringSize); boost::archive::binary_iarchive *ia = new boost::archive::binary_iarchive(is); The last line returns the std::exception: "invalid signature" To be sure that I am not doing something wrong I printed the first 80 characters of this variable when it is created in a 64 bits server and a 32 bits server: In a 64 bits machine server, the print out is: "........serialization::archive.................MonH1F............Efficiency.(cou" (the "." are not printable ascii characters) in Hexa format it is : 16 00 00 00 00 00 00 00 73 65 72 69 61 6C 69 7A 61 74 69 6F 6E 3A 3A 61 72 63 68 69 76 65 04 04 08 04 08 01 00 00 00 06 00 00 00 00 00 00 00 4D 6F 6E 48 31 46 00 00 00 00 1E 00 00 00 00 00 00 00 45 66 66 69 63 69 65 6E 63 79 20 28 63 6F 75 And ind the case of a 32 bits machine server, it is: "....serialization::archive.............MonH1F........Efficiency.(counter2/counte" 16 00 00 00 73 65 72 69 61 6C 69 7A 61 74 69 6F 6E 3A 3A 61 72 63 68 69 76 65 04 04 04 04 08 01 00 00 00 06 00 00 00 4D 6F 6E 48 31 46 00 00 00 00 1E 00 00 00 45 66 66 69 63 69 65 6E 63 79 20 28 63 6F 75 6E 74 65 72 32 2F 63 6F 75 6E 74 65 They are similar but not equal... Thank you, very much Juan Otalora _________________________________________________________________ Explore the seven wonders of the world http://search.msn.com/results.aspx?q=7+wonders+world&mkt=en-US&form=QBRE

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