December 2005 - Boost - lists.boost.org

lvalues and rvalues
by Arkadiy Vertleyb 30 Dec '05

30 Dec '05

Hi, What is current state of the art on l-value/r-value detection? (I know Eric made some progress in the past by using the "?" operator). What we have in typeof is quite primitive :-( I think it might be a good idea to eventially factor it out into a separate header file, and reuse, to avoid contradictions between different libs, and provide the single point of maintenance... Regards, Arkadiy

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yet another asio review
by Jose 30 Dec '05

30 Dec '05

I vote YES to accept asio into boost. Below are some general comments, mostly on what I think should be added. Many thanks to Chris for sharing his expertise and continuing to work on this much needed library ! I have an FC4 x86_64 box and have spent several hours using the library and writing basic examples. I have spent many more hours surveying networking libraries and ensuring I wanted to use asio - documentation and examples It would be nice to add some client/server protocol guidelines that help in designing protocols. Something along the lines on what Chris wrote to compare using the reactor pattern vs using the proactor pattern in asio but geared to different protocols characteristics like fixed header vs variable header, line-oriented, .. The documentation could also include some tips on how to handle special cases raised in the list, like throttling .. An HTTP GET client example would be nice. Not a complete example but maybe an skeleton that can be compiled and shows how asio should be used. No doubt this would be the most used example ! - design This is the main reason I became interested in asio. The design is not only sound but also reflects the practical and wide networking experience of the author - implementation I think the library should use Boost.Threads maybe in addition to the current approach. By using Boost.Threads with asio we'll ensure continued feedback/improvements for two libraries that in many cases will be used together - performance While it has been raised that a synch iostreams interface is nice for basic usage, the major value of C++ asio is performance. I think it would be useful to keep some focus on this, maybe by providing a basic client framework to measure server performance. A basic usage for this would be to compare/benchmark different asio server implementations (latency and throughput). Look forward to the new releases !!

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BCCL : Serialization Concept
by nitin motgi 30 Dec '05

30 Dec '05

Hi, Is there something in the pipeline for BCCL to validate the serialization concept. Thank you, Nitin Motgi NITIN . DOT. MOTGI .AT. GMAIL .DOT. COM

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iterative type registration with typeof
by Arkadiy Vertleyb 30 Dec '05

30 Dec '05

An alternative approach to ones discussed earlier would be to use file iteration, such as: main.cpp----------------------------------- #define BOOST_TYPEOF_COMPLIANT #include <boost/typeof/typeof.hpp> #include <boost/mpl/vector.hpp> #include <boost/preprocessor/iteration/iterate.hpp> #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() BOOST_TYPEOF_REGISTER_TYPE(boost::mpl::vector<>) BOOST_TYPEOF_REGISTER_TYPE(boost::mpl::vector0<>) # define BOOST_PP_ITERATION_LIMITS (1, 10) # define BOOST_PP_FILENAME_1 "register_mpl.hpp" # include BOOST_PP_ITERATE() int main() { boost::mpl::vector1<boost::mpl::vector<int, boost::mpl::vector0<> > > v; typedef BOOST_TYPEOF(v) v_type; return 0; } register_mpl.hpp-------------------------------------------- #include <boost/typeof/typeof.hpp> #define n BOOST_PP_ITERATION() #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() BOOST_TYPEOF_REGISTER_TEMPLATE(boost::mpl::vector, n) BOOST_TYPEOF_REGISTER_TEMPLATE(BOOST_PP_CAT(boost::mpl::vector, n), n) #undef n -------------- This approach can be also applied to sequences. It would work with the current typeof. Regards, Arkadiy

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Re: [boost] Filesystem I18n comments
by Seb Martel 30 Dec '05

30 Dec '05

> > > 2. Any chance of having a non-throwing version of directory_iterator > > (similar > > to status). Since such a common error like not having access to a > > directory > > throws an exception, every directory_iterator construction needs a > > try/catch. > > The recursive_directory_iterator is kind of useless since it will stop as > > soon > > as you get an "access denied". > > (Maybe a portable can_be_iterated function can be added) > > Hum. Worth considering. > I would welcome a non-throwing iterator as well. Most of our path iterating routines are littered with try catches to handle cases that aren't truly exceptional. -Seb

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asio review extended till Dec 30th
by Jeff Garland 30 Dec '05

30 Dec '05

Thanks to everyone for the excellent reviews and discussions of asio! Some folks want additional time for the asio review, so the review will be extended until Dec 30th. Note that Chrisopher may not be able to respond to posts during a significant part of this time due to holiday commitments, but the feedback will eventually be addressed and discussed. In the way of reminder, here's the library details again: Today (Dec 22nd) is the first continuation of the formal review of the Asynchronous I/O library (asio) library by Christopher Kohlhoff. The review will run be extended until Friday December 30th. I will be serving as review manager. From the library synopsis: Boost.Asio is a cross-platform C++ library for network programming that provides developers with a consistent asynchronous I/O model using a modern C++ approach. Downloads of the library as well as online documentation can be found at: http://asio.sourceforge.net/ http://asio.sourceforge.net/boost-asio-proposal-0.3.6/libs/asio/doc/ As usual, please state in review comments how you reviewed the library and whether the you think the library should be accepted into Boost. Further guidelines for writing reviews can be found on the website at: http://www.boost.org/more/formal_review_process.htm#Comments Please review early and often! Thanks, Jeff ******************************************************* A Few Library Details: ******************************************************* Supported Platforms The following platforms and compilers have been tested: * Win32 using Visual C++ 7.1 and Visual C++ 8.0. * Win32 using Borland C++Builder 6 patch 4. * Win32 using MinGW. * Linux (2.4 or 2.6 kernels) using g++ 3.3 or later. * Solaris using g++ 3.3 or later. * Mac OS X 10.4 using g++ 3.3 or later. Rationale The Boost.Asio library is intended for programmers using C++ for systems programming, where access to operating system functionality such as networking is often required. In particular, Boost.Asio attempts to address the following goals: * Portability. The library should support, and provide consistent behaviour across, a range of commonly used operating systems. * Scalability. The library should allow, and indeed encourage, the development of network applications that scale to hundreds or thousands of concurrent connections. The library implementation for each operating system should use the mechanism that best enables this scalability. * Efficiency. The library should support techniques such as scatter-gather I/O, and allow protocol implementations that minimise data copying. * Model Berkeley sockets. The Berkeley sockets API is widely implemented and understood, as well as being covered in much literature. Other programming languages often use a similar interface for networking APIs. * Ease of use. Lower the entry barrier for new users by taking a toolkit, rather than framework, approach. That is, try to minimise the up-front investment in time to just learning a few basic rules and guidelines. After that, a library user should only need to understand the specific functions that are being used. * Basis for further abstraction. The library should permit the development of other libraries that provide higher levels of abstraction. For example, implementations of commonly used protocols such as HTTP. Although the current incarnation of Boost.Asio focuses primarily on networking, its concepts of asynchronous I/O can be extended to include other operating system resources such as files.

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Signals Thread-Safety
by David A. Greene 29 Dec '05

29 Dec '05

I'm starting a project in which I'd hoped to use Boost.Signals but I see that it is not thread-safe. Is there a timeline for making it thread-safe? Thanks. -Dave

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Bug list status
by Marshall Clow 29 Dec '05

29 Dec '05

Six weeks ago: 95 open bugs Five weeks ago: 77 open bugs Four weeks ago: 70 open bugs. Three weeks ago: 64 open bugs. Two week ago: 65 open bugs One week ago: 64 open bugs Today: 61 open bugs Now that 1.33.1 has been released, let's get these bugs cleaned up... Thank you for your cooperation! As Jeff has pointed out, Mike Glassford (threads) and Stephen Cleary (pool) have been MIA for quite a while. If anyone wants to contribute fixes for their libraries, let me (or Jeff) know! If you think that a bug has been assigned incorrectly, please let me know. Bug counts per assignee: Mike Glassford 13 Doug Gregor 8 Stephen Cleary (shammah) 6 Joerg Walter 4 Beman Dawes 3 Joel de guzman (djowel) 3 Jeff Garland (az_sw_dude) 3 Jeremy Siek 3 Jonathan Turkanis 3 John R. Bandela 2 Eric Friedman (ebf) 2 John Maddock 2 Thorsten Ottosen (nesotto) 2 Vladimir Prus 1 Kevlin Henney 1 Hubert Holin 1 Samuel Kremp 1 Jens Maurer 1 Rene Rivera (grafik) 1 Daniel Wallin 1 Here are the currently opened bugs, sorted by assignee. Assignee: az_sw_dude <http://sourceforge.net/users/az_sw_dude/> Summary: wrong usage of ios_base::narrow Bug #: 989487 <http://sourceforge.net/tracker/index.php?func=detail&aid=989487&group_id=75…> Assignee: az_sw_dude <http://sourceforge.net/users/az_sw_dude/> Summary: date_time type conversion warning Bug #: 1069225 <http://sourceforge.net/tracker/index.php?func=detail&aid=1069225&group_id=7…> Assignee: az_sw_dude <http://sourceforge.net/users/az_sw_dude/> Summary: local_adjustor::utc_to_local throws 'Time label invalid' Bug #: 1220011 <http://sourceforge.net/tracker/index.php?func=detail&aid=1220011&group_id=7…> Assignee: beman_dawes <http://sourceforge.net/users/beman_dawes/> Summary: clock is not portable Bug #: 788762 <http://sourceforge.net/tracker/index.php?func=detail&aid=788762&group_id=75…> Assignee: beman_dawes <http://sourceforge.net/users/beman_dawes/> Summary: boost::filesystem::exists has bugs with UNC paths Bug #: 1164057 <http://sourceforge.net/tracker/index.php?func=detail&aid=1164057&group_id=7…> Assignee: beman_dawes <http://sourceforge.net/users/beman_dawes/> Summary: Problems with native_file_string() on windows Bug #: 1378631 <http://sourceforge.net/tracker/index.php?func=detail&aid=1378631&group_id=7…> Assignee: daniel_wallin <http://sourceforge.net/users/daniel_wallin/> Summary: [Parameter] Docco error section 2.7.2 Bug #: 1378446 <http://sourceforge.net/tracker/index.php?func=detail&aid=1378446&group_id=7…> Assignee: dgregor <http://sourceforge.net/users/dgregor/> Summary: EdgeListS = setS for adjacency_list does not work Bug #: 1163077 <http://sourceforge.net/tracker/index.php?func=detail&aid=1163077&group_id=7…> Assignee: dgregor <http://sourceforge.net/users/dgregor/> Summary: LEDA graph adaptors do not handle hidden nodes properly Bug #: 1168431 <http://sourceforge.net/tracker/index.php?func=detail&aid=1168431&group_id=7…> Assignee: dgregor <http://sourceforge.net/users/dgregor/> Summary: random_vertex/random_edge are unnecessarily inefficient Bug #: 1204684 <http://sourceforge.net/tracker/index.php?func=detail&aid=1204684&group_id=7…> Assignee: dgregor <http://sourceforge.net/users/dgregor/> Summary: Document copy_component Bug #: 1204688 <http://sourceforge.net/tracker/index.php?func=detail&aid=1204688&group_id=7…> Assignee: dgregor <http://sourceforge.net/users/dgregor/> Summary: reverse_graph and constness of property maps Bug #: 1246336 <http://sourceforge.net/tracker/index.php?func=detail&aid=1246336&group_id=7…> Assignee: dgregor <http://sourceforge.net/users/dgregor/> Summary: html docs frequently missing key words Bug #: 1294420 <http://sourceforge.net/tracker/index.php?func=detail&aid=1294420&group_id=7…> Assignee: dgregor <http://sourceforge.net/users/dgregor/> Summary: EdgeListS = has_setS for adjacency_list does not work Bug #: 1352049 <http://sourceforge.net/tracker/index.php?func=detail&aid=1352049&group_id=7…> Assignee: dgregor <http://sourceforge.net/users/dgregor/> Summary: predicates without default constructor fail to compile (2) Bug #: 1353875 <http://sourceforge.net/tracker/index.php?func=detail&aid=1353875&group_id=7…> Assignee: djowel <http://sourceforge.net/users/djowel/> Summary: Miss ' = ParserT()' Bug #: 907299 <http://sourceforge.net/tracker/index.php?func=detail&aid=907299&group_id=75…> Assignee: djowel <http://sourceforge.net/users/djowel/> Summary: spirit insert_key_actor.hpp Bug #: 1059936 <http://sourceforge.net/tracker/index.php?func=detail&aid=1059936&group_id=7…> Assignee: djowel <http://sourceforge.net/users/djowel/> Summary: Another config correction for Sun C++ Bug #: 1220782 <http://sourceforge.net/tracker/index.php?func=detail&aid=1220782&group_id=7…> Assignee: ebf <http://sourceforge.net/users/ebf/> Summary: boost::blank - missing operators Bug #: 1191356 <http://sourceforge.net/tracker/index.php?func=detail&aid=1191356&group_id=7…> Assignee: ebf <http://sourceforge.net/users/ebf/> Summary: [variant] Bug in recursive_wrapper_fwd.hpp Bug #: 1359257 <http://sourceforge.net/tracker/index.php?func=detail&aid=1359257&group_id=7…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: timeconv.inl to_duration() nsec error Bug #: 548104 <http://sourceforge.net/tracker/index.php?func=detail&aid=548104&group_id=75…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: Solaris - once.cpp compile error Bug #: 549162 <http://sourceforge.net/tracker/index.php?func=detail&aid=549162&group_id=75…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: AIX 4.3 SIGSEGV at thread termination Bug #: 551577 <http://sourceforge.net/tracker/index.php?func=detail&aid=551577&group_id=75…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: boost::threads uses msvc only function? Bug #: 568951 <http://sourceforge.net/tracker/index.php?func=detail&aid=568951&group_id=75…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: BCB6 throw EExternelException Bug #: 596149 <http://sourceforge.net/tracker/index.php?func=detail&aid=596149&group_id=75…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: thread_cleanup problems Bug #: 649291 <http://sourceforge.net/tracker/index.php?func=detail&aid=649291&group_id=75…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: Mac implementation of threads is CPU hog Bug #: 885045 <http://sourceforge.net/tracker/index.php?func=detail&aid=885045&group_id=75…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: xtime_cmp: use comparison not subtraction Bug #: 993272 <http://sourceforge.net/tracker/index.php?func=detail&aid=993272&group_id=75…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: condition variables and recursive_mutex Bug #: 1072605 <http://sourceforge.net/tracker/index.php?func=detail&aid=1072605&group_id=7…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: compiler error on Mac implementation of threads Bug #: 1201779 <http://sourceforge.net/tracker/index.php?func=detail&aid=1201779&group_id=7…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: timeconv.inl line 116 copy/paste error Bug #: 1239052 <http://sourceforge.net/tracker/index.php?func=detail&aid=1239052&group_id=7…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: Exception safety in class 'thread' Bug #: 1305885 <http://sourceforge.net/tracker/index.php?func=detail&aid=1305885&group_id=7…> Assignee: glassfordm <http://sourceforge.net/users/glassfordm/> Summary: mistake in documentation of condition Bug #: 1364416 <http://sourceforge.net/tracker/index.php?func=detail&aid=1364416&group_id=7…> Assignee: grafik <http://sourceforge.net/users/grafik/> Summary: boost jam problem with parallel builds Bug #: 1234224 <http://sourceforge.net/tracker/index.php?func=detail&aid=1234224&group_id=7…> Assignee: hubert_holin <http://sourceforge.net/users/hubert_holin/> Summary: Cannot compile octonion_test.cpp because of bug in sinc.hpp Bug #: 751289 <http://sourceforge.net/tracker/index.php?func=detail&aid=751289&group_id=75…> Assignee: jbandela <http://sourceforge.net/users/jbandela/> Summary: Compiler error for tokenizer on Solaris Bug #: 976241 <http://sourceforge.net/tracker/index.php?func=detail&aid=976241&group_id=75…> Assignee: jbandela <http://sourceforge.net/users/jbandela/> Summary: token_iterator::at_end() result is inversed Bug #: 1338326 <http://sourceforge.net/tracker/index.php?func=detail&aid=1338326&group_id=7…> Assignee: jmaurer <http://sourceforge.net/users/jmaurer/> Summary: Diff in state of mersenne_twister gen between GCC3.41 & CW9 Bug #: 1115124 <http://sourceforge.net/tracker/index.php?func=detail&aid=1115124&group_id=7…> Assignee: joerg_walter <http://sourceforge.net/users/joerg_walter/> Summary: bug in ublas/storage.hpp Bug #: 1095697 <http://sourceforge.net/tracker/index.php?func=detail&aid=1095697&group_id=7…> Assignee: joerg_walter <http://sourceforge.net/users/joerg_walter/> Summary: dead links in uBLAS page Bug #: 1169273 <http://sourceforge.net/tracker/index.php?func=detail&aid=1169273&group_id=7…> Assignee: joerg_walter <http://sourceforge.net/users/joerg_walter/> Summary: Documentation not available on web site: Bug #: 1228242 <http://sourceforge.net/tracker/index.php?func=detail&aid=1228242&group_id=7…> Assignee: joerg_walter <http://sourceforge.net/users/joerg_walter/> Summary: uBLAS::subslice doesn't work Bug #: 1292635 <http://sourceforge.net/tracker/index.php?func=detail&aid=1292635&group_id=7…> Assignee: johnmaddock <http://sourceforge.net/users/johnmaddock/> Summary: Adding boost::is_complex to type_traits.hpp Bug #: 1315712 <http://sourceforge.net/tracker/index.php?func=detail&aid=1315712&group_id=7…> Assignee: johnmaddock <http://sourceforge.net/users/johnmaddock/> Summary: _GLIBCXX_DEBUG fails on 1.33.1 - bug or design? Bug #: 1391875 <http://sourceforge.net/tracker/index.php?func=detail&aid=1391875&group_id=7…> Assignee: jsiek <http://sourceforge.net/users/jsiek/> Summary: invalid result for File Dependency Examp Bug #: 551110 <http://sourceforge.net/tracker/index.php?func=detail&aid=551110&group_id=75…> Assignee: jsiek <http://sourceforge.net/users/jsiek/> Summary: Spelling of Edmonds-Karp-Algorithm Bug #: 1226292 <http://sourceforge.net/tracker/index.php?func=detail&aid=1226292&group_id=7…> Assignee: jsiek <http://sourceforge.net/users/jsiek/> Summary: g++ v3.2.3 inker error for read_graphviz ih boost v1.33.1 Bug #: 1378907 <http://sourceforge.net/tracker/index.php?func=detail&aid=1378907&group_id=7…> Assignee: kevlin <http://sourceforge.net/users/kevlin/> Summary: lexical_cast & pure virtual functions & VC 8 STL Bug #: 1358600 <http://sourceforge.net/tracker/index.php?func=detail&aid=1358600&group_id=7…> Assignee: nesotto <http://sourceforge.net/users/nesotto/> Summary: boost.range and 'const char[]'. Bug #: 1272315 <http://sourceforge.net/tracker/index.php?func=detail&aid=1272315&group_id=7…> Assignee: nesotto <http://sourceforge.net/users/nesotto/> Summary: [Boost.Range]boost::const_begin calls non-qualified 'begin' Bug #: 1361686 <http://sourceforge.net/tracker/index.php?func=detail&aid=1361686&group_id=7…> Assignee: samuel_k <http://sourceforge.net/users/samuel_k/> Summary: format: assert when parsing invalid pattern Bug #: 1326132 <http://sourceforge.net/tracker/index.php?func=detail&aid=1326132&group_id=7…> Assignee: shammah <http://sourceforge.net/users/shammah/> Summary: ct_gcd_lcm.hpp compilation error Bug #: 558174 <http://sourceforge.net/tracker/index.php?func=detail&aid=558174&group_id=75…> Assignee: shammah <http://sourceforge.net/users/shammah/> Summary: test_pool_alloc.cpp not compile CW8.1 Bug #: 586779 <http://sourceforge.net/tracker/index.php?func=detail&aid=586779&group_id=75…> Assignee: shammah <http://sourceforge.net/users/shammah/> Summary: pool::purge_memory() does not reset next_size Bug #: 984124 <http://sourceforge.net/tracker/index.php?func=detail&aid=984124&group_id=75…> Assignee: shammah <http://sourceforge.net/users/shammah/> Summary: Borland compiler error with Pool, boost::pool_allocator Bug #: 988124 <http://sourceforge.net/tracker/index.php?func=detail&aid=988124&group_id=75…> Assignee: shammah <http://sourceforge.net/users/shammah/> Summary: perfomance: memory cleanup for pool takes too long Bug #: 995270 <http://sourceforge.net/tracker/index.php?func=detail&aid=995270&group_id=75…> Assignee: shammah <http://sourceforge.net/users/shammah/> Summary: boost::pool_allocator breaks with vector of vectors Bug #: 1179641 <http://sourceforge.net/tracker/index.php?func=detail&aid=1179641&group_id=7…> Assignee: turkanis <http://sourceforge.net/users/turkanis/> Summary: rational operator&lt; can overflow Bug #: 798357 <http://sourceforge.net/tracker/index.php?func=detail&aid=798357&group_id=75…> Assignee: turkanis <http://sourceforge.net/users/turkanis/> Summary: boost::rational documentation typos(?) Bug #: 1043616 <http://sourceforge.net/tracker/index.php?func=detail&aid=1043616&group_id=7…> Assignee: turkanis <http://sourceforge.net/users/turkanis/> Summary: problem with boost::iostreams when compiled with Visual C++ Bug #: 1365752 <http://sourceforge.net/tracker/index.php?func=detail&aid=1365752&group_id=7…> Assignee: vladimir_prus <http://sourceforge.net/users/vladimir_prus/> Summary: multitoken broken in program_options 1.33 Bug #: 1266877 <http://sourceforge.net/tracker/index.php?func=detail&aid=1266877&group_id=7…> -- -- Marshall Marshall Clow Idio Software <mailto:marshall@idio.com> It is by caffeine alone I set my mind in motion. It is by the beans of Java that thoughts acquire speed, the hands acquire shaking, the shaking becomes a warning. It is by caffeine alone I set my mind in motion.

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[asio] Library Review
by Ronald Garcia 29 Dec '05

29 Dec '05

I have reviewed ASIO by browsing some of the documentation and working through the tutorial. What follows are my comments on the library. Regarding the Tutorial: Some of the tutorial material seems too low-level with respect to the facilities available from the C++ Standard Library. Why the use of char arrays, strdup, and strlen? Furthermore, is strdup a standard C++ function? I do not think it is standard C. I would like to see an interface for reading/writing that supports iterators if that makes sense. It would also be nice to be able to read from a socket into an std::string. If that is possible, then it is not obvious from the tutorial. Based on the daytime tutorial, I am concerned that not enough high-level functionality has been added to the library. The daytime examples still have the flavor of using unix sockets. I think that this low-level functionality is critical to flexibility (and perhaps performance), but I would like to be able to quickly construct simple network applications as well. Just for some perspective, here's a tcp daytime server written in the TCL scripting language: -----<snip>----- #!/bin/sh # Standard Trick \ exec tclsh $0 ${1+"$@"} proc serveMe {handle addr port} { puts $handle [clock format [clock seconds]] close $handle } set sk [socket -server serveMe 13] vwait forever -----<snip>----- and here's a tcp datetime client: -----<snip>----- #!/bin/sh # Standard Trick \ exec tclsh $0 ${1+"$@"} if { $argc != 1} { puts stderr "client <host>" exit 1 } set sk [socket [lindex $argv 0] 13] puts -nonewline [read $sk] -----<snip>----- I would like to see an interface at this coarse-grain a level of functionality as well (using the analogous Modern C++ idioms of course). I did not find the Timer 5 example (Using boost threads) to be very compelling. Granted the examples are meant to give a flavor of the library interface, but it may be more compelling to defer multi-threading to the daytime server, perhaps forking a new thread on each connection. This would probably more closely resemble a real use of the facility. I suspect that something more would need to be done to demonstrate synchronization. I am also curious if the library could provide synchronous networking (which asio supports contrary to the library's name) through an iostreams-like interface as well. Demuxer: It appears that any application that uses asio must have one and only one demuxer object floating around. If that is the case, then perhaps it would be wise to model demuxer after std::cout: a global object that is implicitly constructed and destructed and available to any translation unit that includes the relevant header. Demuxer appears to have a more general use than merely i/o. In fact it appears that demuxer could be generally applicable to other asynchronous event handling that might occur in a C++ application (Graphical User Interface come immediately to mind). Existing libraries for GUI's have their own event loop systems. Two issues to consider are: 1) Might future libraries that require asynchrony piggyback off of ASIO's demultiplexing facilitites (For example a C++ GUI library, etc). 2) How can one interleave asio's demultiplexing facilities with other existing event-based libraries. I'm afraid I have not had time to investigate whether and how this can be done in asio currently. But some applications will require mixing asio into some other master event loop. Something of like demuxer::run_one_event() would be a good start. Documentation: The reference documentation seems to be quite good. I do not see documentation for the default class types (such as demuxer) written without reference to the underlying policies involved. It would be very helpful to basic users of the library to have higher-level documentation available in addition to the detailed lower-level documentation. There appear to be some gaps in the documentation on first view (No documentation of the Demuxer_Service concept (modeled by demuxer_service). Code Comments: It was necessary for me to make the following changes to the library in order to prevent warnings and to compile under OS X (Panther/10.3): OS X 10.3 does not define EV_OOBAND. To compile the programs, I had to supply a definition to kqueue_reactor.hpp: #define EV_OOBAND EV_FLAG1 It is not clear to me that this is the proper fix. Furthermore, it was necessary for me to supply some casts in socket_ops.hpp to prevent warnings: recv_bufs[i].iov_len = static_cast<int>(b[i].size); recv_bufs[i].iov_base = static_cast<caddr_t>(b[i].data); ... send_bufs[i].iov_len = static_cast<int>(b[i].size); send_bufs[i].iov_base = static_cast<caddr_t>(b[i].data); Cheers, ron

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[asio] timer questions
by Andrew Schweitzer 29 Dec '05

29 Dec '05

*Maybe there should be a "run_forever" version of demuxer::run? If I read the docs correctly, demuxer::run will exit if it has nothing left to do. So if the last timer expires, run will exit. The next time a timer is started demuxer::reset and demuxer::run must be called again or nothing will happen. Is this correct? Could this happen for sockets as well, if user never called a function like read or accept that will sit there forever until something happens? For example, if a client problem calls run, does an async connect, sends some data, but doesn't do a read, then would run stop after the send completed? Or would run wait for socket to be closed? *It looks like deadline_timer objects need to be dynamically allocated, right? It looks to me that when they destruct they stop themselves. I think this means that there are two dynamic allocations per timer started, one for the implementation and one for the "handle". Could this be avoided? Not sure avoiding it is worth the trouble. In any case, this probably needs to be documented. *Since user must allocate each deadline_timer (assuming above correct), then user must remember to toss them when timer completes. It might be nice if this could be handled automatically. *There aren't really unique IDs for timers, right? The address of the timer object must be unique as long as the timer is running, but after the timer completes it could be re-used for another timer, so that doesn't seem like a great idea. Does anyone else think unique timer IDs belong in the library? I'm not sure it's requirement, but most timer code I've worked on has used a unique ID. It's not hard for the application to provide this, but it is a bit more work.

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