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How to deal with the exception " End of File"
by mcheng 17 Jul '12

17 Jul '12

Hi all: I have check the thread which was talking about "end of file" problem. I have the same issue and I have no idea about when the socket be closed by program. The author said that he fixed the bug after debugging finally but he didn't show the way to solve the problem and where was the bug is~ Can some body give me some hint about it ? Thanks Cheer~ Cheng Mo Beijing Jaeger Communication Electronic Technology Co., Ltd. Addr: Floor2B Dingjun Plaza No.75 Suzhou Street, 100080, Beijing, China Mail: mcheng(a)pbicn.com

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[context] Release date?
by Szymon Gatner 17 Jul '12

17 Jul '12

Hey, boost.context has been accepted quite some time ago, is there any eta on when it is going be officially part of boost? asio (for async task running) + context (as a coroutine/continuation) == pure win -- Szymon Gatner The Lordz Games Studio www.thelordzgamesstudio.com

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compile asio against static boost libs
by Sergiy Nazarenko 17 Jul '12

17 Jul '12

Hi all! I would like to compile my project against static libraries If I compile my project in following manner: c++ -I/usr/local/include/boost/1.49.0/ -c -o azio.o azio.cpp c++ -L/usr/local/lib64/boost/1.49.0/ azio.o -lboost_system -o bin/azio It is OK. But if I use static libraries: c++ -I/usr/local/include/boost/1.49.0/ -c -o azio.o azio.cpp c++ -L/usr/local/lib64/boost/1.49.0/ azio.o /usr/local/lib64/boost/1.49.0/libboost_system.a -o bin/azio I have got error: azio.o: In function `boost::asio::detail::posix_tss_ptr_create(unsigned int&)': azio.cpp:(.text._ZN5boost4asio6detail20posix_tss_ptr_createERj[boost::asio::detail::posix_tss_ptr_create(unsigned int&)]+0x19): undefined reference to `pthread_key_create' azio.o: In function `boost::asio::detail::posix_thread::~posix_thread()': ........ ........ boost::asio::detail::task_io_service::thread_info>::context>::operator=(boost::asio::detail::call_stack<boost::asio::detail::task_io_service, boost::asio::detail::task_io_service::thread_info>::context*)]+0x20): undefined reference to `pthread_setspecific' collect2: ld returned 1 exit status I used strings to know where is function pthread_key_create. I found in libboost_thread.so. Next my step was: c++ -L/usr/local/lib64/boost/1.49.0/ azio.o /usr/local/lib64/boost/1.49.0/libboost_system.a /usr/local/lib64/boost/1.49.0/libboost_thread.a -o bin/azio I've try out to mix up places libraries and object file c++ .. azio.o libboost_system.a libboost_thread.a -o bin/azio c++ .. libboost_system.a libboost_thread.a azio.o -o bin/azio c++ .. libboost_thread.a azio.o libboost_system.a -o bin/azio But error is still. Thanx, Sergiy

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[boost] conversion review report
by Gordon Woodhull 16 Jul '12

16 Jul '12

Hi Vicente, all, Profuse apologies for the long delay in writing this report. Cheers, Gordon Report on Boost Conversion Library Review, August 20-29, 2011. I want to thank Vicente Botet Escriba for submitting the Conversion library for review and for his general good nature in receiving criticism and alternate designs. The Conversion library presents a general framework for plugging in conversion operations between arbitrary types, providing a consistent interface for type-to-type conversions. The library is unfortunately rejected. During the review, there were two votes for acceptance and two against, and some interesting conversation from about a dozen participants. The major reason the library can't be accepted in its current form is that there was near consensus that there is no universal conversion domain, especially when the source or destination type might be a string. Much of the review focused on possible One Definition Rule (ODR) violations, which are a consequence of having a universal customization point using template specializations or function overloads. Many solutions were offered, which will make up the second part of this report, "How to Avoid Universality." I. Concerns about the library Conversions Are Not Generic? While some reviewers didn't see the need for a generic conversion library (and I was a little surprised at the vehemence of their opinions), I don't see this in itself as a reason to reject the library. The library's stated purpose is to provide a common interface for general type <-> type conversions, like lexical_cast does for string <-> type conversions. However, it was interesting that seemingly no one could come up with applications of truly generic conversion, although Jeffrey Lee Hellrung and Antony Polukhin alluded to their existence. Also, some reviewers pointed out that you often need to choose what kind of conversion to do, and a generic library can get in the way here. Strings are the most obvious example: if you are converting from a string representing a binary value it would not work to use a decimal converter. Antony Polukhin pointed out a more subtle example: "lexical_cast<char>(1) and numeric_cast<char>(1) will produce different output." Jeff Hellrung summed this point up nicely: "I think it's certainly possible for different clients using the same generic component to want different conversion implementations for a given pair of types, and that point, Boost.Conversion's universally-defined conversion implementations become useless. One wants the conversion operation to be parametrized as well as the types involved in the conversion." Multi-Client Specialization Concerns Leaving aside possible ODR violations, which we'll return to in Part II, some reviewers questioned the scalability of using template specialization and overloads when many clients (i.e. independent headers) may be customizing the behavior. Vladimir Batov claimed that a system which allows partial specializations on both Source and Target can't be made to work generally. Jeroen Habraken said SFINAE/enable_if "does make code fragile". I'm not clear if these conversations were resolved (or resolvable ;). Non-Generic Solutions Some reviewers objected that conversions should just be defined within individual libraries, but of course this begs the question (as came up recently on the ML between DateTime and Chrono), "which library should house the conversions?" Others (such as Phil Endecott) thought that simple c-style functions such as rgb_to_cmyk() were more explicit and direct. Why is this so complex? Kevlin Henney, initially excited about a general solution to the problem which lexical_cast first set out, commented on the documentation: "Based on casual reading, it feels a little more complex and requires a higher-entry level of knowledge than would be appropriate for many of the people who actually need this functionality." II. How to Avoid Universality One of the positive results of this review was a small catalog of alternatives to a universal customization point involving template specialization or overloaded functions. a. Avoid the Problem In the strictest sense, any library which allows either kind of universal customization can be prone to ODR violations. But many reviewers particularly thought that a customization point involving two UDTs was especially dangerous. To his credit, Vicente was very up-front about the limitations of his design, and attempted to formulate rules for how the library could be used safely. In the documentation, he suggests (IIUC) that header-only libraries could use generic conversions as long as they don't define them, or define them as long as they don't use them. http://tinyurl.com/cmbgyfk b. Inherited tags John Bytheway suggested a tag-dispatch system where conversions are tagged with their source library, and any library which depends on conversions from two libraries would define a tag which inherits from the tags of both libraries. Thus ODR violations are avoided at the expense of having to specify an extra tag (effectively a sort of global conversion domain). http://lists.boost.org/Archives/boost/2011/08/184836.php c. Conversion Domains and Overloaded Function Objects Going on the consensus that there is no universal conversion domain, your humble review manager suggested a metaprogramming solution that defines conversion domain objects which combine a set of conversions within an object. http://lists.boost.org/Archives/boost/2011/08/185259.php A more general solution would be to create an overloaded polymorphic function object, much like a polymorphic-source version of Lorenzo Caminiti's OverloadedFunction library (http://tinyurl.com/72nolyj) However, I have been warned (by Daveed Vandevoorde) that the rules for function overloading are too dangerously complicated to implement in a metaprogram. d. Boost.Dispatch Matthias Gaunard announced that he is working on a library particularly to "solve the problem of specializing a function template for a category of types with best-match selection." http://lists.boost.org/Archives/boost/2011/08/185286.php e. Abuse of Unnamed Namespaces Emil Dotchevski suggested that "It might be possible to abuse unnamed namespaces to avoid violating ODR". I'm not clear if this was a serious suggestion as it wasn't spelled out. :) f. GIL's solution (?) Christian Henning wrote: "GIL has such functionality. I like their way of structuring conversion." However, I was not able to find a description of this mechanism for the report. Thanks to everyone who participated in the review! _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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Re: [Boost-users] testing archive version of boost::serialize
by Sam Appleton 16 Jul '12

16 Jul '12

Hi Robert Thanks for replying. I realize perhaps I was not clear or do not fully understand your answer. I was not really looking for ways to test my archive class. Let's say I know I have an archive file that's been generated by my archival class, but it has an indeterminate version that may or may not be compatible with the present version. In order for me to determine the embedded version of the archive, the only way I know of is to just attempt to deserialize (I do this using (archive-stream) >> (object) ; ) and seeing if a version incompatability is flagged. However, is there any way to determine just from an open archive stream what the version number of the embedded stream or classes implied by the stream contains? Sam >Check the documentation section Reference/Archive Class Reference/Testing > >This explains how you can submit your archive class to the exhaustive >series of tests that all the "built-in" archives are subjected to. It does >take a while to run the tests. And then it makes even more time to >get your custom archive to pass all the tests. But you will be >rewarded with something you should be able to depend upon. > >Robert Ramey -- -- Sam Appleton CEO, Ausdia Inc. o: (408) 914 2704 x801 f: (408) 914 2704 c: (650) 242 2908 Email sam(a)ausdia.com Skype samsappleton

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[1.50.0] PDF documentation available
by John Maddock 15 Jul '12

15 Jul '12

With apologies for being so late with these.... The PDF build of Boost's documentation for 1.50 is available from the usual SF site: https://sourceforge.net/projects/boost/files/boost-docs/1.50/ John.

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testing archive version of boost::serialize
by Sam Appleton 14 Jul '12

14 Jul '12

Is there any way to "test" the version of a boost serialization archive. I know that we can always just attempt to deserialize and catch the generated exception, but is there any way to just test the version of the archive before attempting deserialization? Best Sam Appleton

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aiso signal handling, daemon shutdown
by Kraus Philipp 13 Jul '12

13 Jul '12

Hello, I try to create a working example for a daemon with http://www.boost.org/doc/libs/1_50_0/doc/html/boost_asio/overview/signals.h… I have created a program like: static bool run = true; void handler( const boost::system::error_code& error, int signal_number) { if (!error) { run = false; std::cout << "signal" << std::endl; } } and the main with int main(..) { boost::asio::io_service io_service; boost::asio::signal_set signals(io_service, SIGINT, SIGTERM); signals.async_wait(handler); while (run) { boost::this_thread::yield(); } } The program runs, but if I do "kill pid" the program does not stop or shows the message. I would like to create a small daemon which runs some threads and can stop with the normal stop signal and can reload the configuration on reload. Can anyone help me to create a working example first !? Thanks a lot Phil

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mult_array view question
by Petros 13 Jul '12

13 Jul '12

Hi, I have the following question: The documentation describes how to obtain an array view for a small number of dimensions by repeated application of the [] operator of boost::indices. Is there a way to do it in a single call, bypassing the C-type notation? Say, I have a five dimensional multi_array (ma, henceforth) and want to get a slice in one dimension. Is there a call to do this ? I am looking for a generic answer. TIA, Petros PS: was hoping that the ranges_ field of extent_gen could do the trick, since all the info is there - I know it’s in the detail namespace which practically means private/subject-to-change but had no better idea.

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What algorithms for solving the Shortest Paths problem are implemented in BOOST?
by Alex Sadovsky 13 Jul '12

13 Jul '12

I know, Dijkstra's and the Bellman-Ford one are. Is Dial's? http://dl.acm.org/citation.cfm?id=363610 Thanks, Al

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