February 2009 - Boost-users - lists.preview.boost.org

[Range] Single Pass Range functionality
by Edward Diener 23 Feb '09

23 Feb '09

In the Boost Range documentation describing the Range concepts for a single pass range it lists in the expression semantics post-condition for boost::begin(a): "boost::begin(a) is either dereferenceable or past-the-end. It is past-the-end if and only if boost::distance(a) == 0." However the documentation for single pass range does not list boost::distance as a valid expression nor in the reference section is boost::distance listed as a single pass range function. Is boost::distance a valid function when applied to a single pass range ?

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asio: take back ownership of native descriptor
by Koen Deforche 23 Feb '09

23 Feb '09

Dear all, We have been enjoying using asio alot to build cross-platform networking applications. Just recently, however, we have encountered a limitation that seems impossible to work around, and, would only require a small addition in the API to accomodate. We are trying to add one or more native socket descriptors into asio's reactor to be informed when it is possible to write or read from these descriptors. Therefore, we are creating a tcp::socket and assign() to it a native descriptor. This works, but it seems that nothing can prevent asio from closing the connection in ~tcp::socket() (which does not seem logic since asio did not open the connection in the first place). Should there not be a method to 'take' (back) the descriptor from the asio socket, which resets the socket to the same state as its default constructor ? We tried the workaround that was suggested on the mailinglist, which is to dup() the descriptor. This works on Linux. Unfortunately, dup() is not available on Windows platforms, and when trying to workaround this by using Windows' native methods, we hit the same (so far, unsolved?) problem of this post: http://thread.gmane.org/gmane.comp.lib.boost.user/44269 Regards, koen

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How to implementing a conditional wait
by Daniele Barzotti 23 Feb '09

23 Feb '09

Hi, I have to do a simple task, but I'm quite confused. I have a class that sends some data on RS232 and wait for a answer. (What in Windows is WaitForSingleObject) void ATDispatcher::OnDataReveived() { // Data received from RS232 serial_port.GetData(&buffer); boost::lock_guard<boost::mutex> lock(mut); data_ready = true; cond.notify_one(); }; void ATDispatcher::AtDispatcher(SerialPort& device) : _device(device) { // Connecting the slot for receiving event _device.OnData(boost::bind(&ATDispatcher::OnDataReceived(), &this)); }; int ATDispatcher::SendCommand(std::string cmd, bool waitOK = true, bool decode_answer = true int cmd_timeout = COMMAND_TIMEOUT) { boost::unique_lock<boost::mutex> lock(mut); boost::xtime xt; xtime_get(&xt,boost::TIME_UTC); xt.sec += cmd_timeout; data_ready = false; //Send data.... while(!data_ready) { cond.timed_wait(lock, xt); } }; Ok, The OnDataReceived is called from the SerialPort thread when the data is available. In the SendCommand I have to wait for a timeout or until the answer is arrived...how can I do it? Thanks! Daniele.

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[1.38.0] PDF package of Boost documentation released.
by John Maddock 22 Feb '09

22 Feb '09

Folks, A package containing PDF versions of Boost's documentation is now available for Boost-1.38.0 from the usual sourceforge download site: http://sourceforge.net/project/showfiles.php?group_id=7586&package_id=15971… Please note that due to the diverse range of tools in use within Boost it has not been possible to produce PDF's for all of Boost's libraries, those currently included as PDF's are: accumulators any array asio bimap range complex-tr1 concepts config conversion date_time foreach function hash interprocess intrusive iterator math-gcd math mpi octonion optional phoenix program_options proto python_tutorial quaternion ref regex scope_exit signals static_assert string_algo thread tr1 tribool type_traits typeof units unordered variant xpressive Documentation for the following tools are also included in this package: bjam boost_build boostbook quickbook Regards, John Maddock.

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boost::iostreams : equivalent of std::getline() in boost
by vandamme 22 Feb '09

22 Feb '09

Hello ! I want to use boost to read a text file like this : boost::iostreams::file_source file(filename.c_str()); But, when I want to get each single line with getline(), it doesn't compile : while (std::getline(file, line)) { ...} // COMPILATION ERROR What's the equivalent in boost for std::getline() ? Thks. -- View this message in context: http://www.nabble.com/boost%3A%3Aiostreams-%3A-equivalent-of-std%3A%3Agetli… Sent from the Boost - Users mailing list archive at Nabble.com.

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Boost.Test: How to create a multi-module (multi-file) test suite or how to link multiple auto test cases into one executable?
by Leonid Shlyapnikov 22 Feb '09

22 Feb '09

Hi everybody! I got a bit rusty with C++. Can someone help me to understand how I can create a Boost.Test suite that contains test cases from multiple modules (multiple cpp files)? Lets say I have: file: ATest.cppp: ----------------------------------------------------------------------- #define BOOST_TEST_MODULE ATest #include <boost/test/included/unit_test.hpp> BOOST_AUTO_TEST_CASE(testA1) { .... } BOOST_AUTO_TEST_CASE(testA2) { .... } ----------------------------------------------------------------------- file: BTest.cppp: ----------------------------------------------------------------------- #define BOOST_TEST_MODULE BTest #include <boost/test/included/unit_test.hpp> BOOST_AUTO_TEST_CASE(testB1) { .... } BOOST_AUTO_TEST_CASE(testB2) { .... } ----------------------------------------------------------------------- Compilation passes all right. Linker gives: In function `boost::unit_test::output::compiler_log_formatter::log_finish(std::basic_ostream<char, std::char_traits<char> >&)': /usr/include/c++/4.2/bits/char_traits.h:291: multiple definition of `boost::unit_test::output::compiler_log_formatter::log_finish(std::basic_ostream<char, std::char_traits<char> >&)' I understand this error (even after 3-4 years of only Java :). So, question: Is there any way to link multiple auto test cases into one executable file? I have not found any information on this. Does it mean that if I want to have one executable that runs all my test cases I need to put/include all test case definitions into one cpp file? Thanks a lot, Leonid Shlyapnikov

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bjam cross compilation using mingw32 doesn't use mingw32-ar ?
by Ákos Maróy 22 Feb '09

22 Feb '09

I'm trying to cross-compile boost using mingw32, doing the following steps: echo "using gcc : : mingw32-g++ ;" >> user-config.jam bjam target-os=windows threading=multi threadapi=win32 link=static runtime-link=static --prefix=../../usr-mingw --includedir=../../usr-mingw/include --libdir=../../usr-mingw/lib install this goes down fine. but when I'm trying to link to one of the boost libraries, I get the following: mingw32-g++ -m32 -g -L../../usr-mingw/lib -o tests test_plane_position.o test_position_recorder.o test_position_player.o plane_position.o position_recorder.o position_player.o tests.o -llibboost_test_exec_monitor-mgw41-mt-s-1_38 -llibboost_unit_test_framework-mgw41-mt-s-1_38 ../../usr-mingw/lib/libboost_test_exec_monitor-mgw41-mt-s-1_38.lib: could not read symbols: Archive has no index; run ranlib to add one collect2: ld returned 1 exit status make: *** [tests] Error 1 where: $ file ../../usr-mingw/lib/libboost_unit_test_framework-mgw41-mt-s-1_38.lib ../../usr-mingw/lib/libboost_unit_test_framework-mgw41-mt-s-1_38.lib: current ar archive I did some search, and one suggestion was that the build process didn't use mingw32-ar for creating the libraries? if so, how could I make bjam use mingw32-ar instead of just ar? or is something else the issue? Akos (of course I could just run ranlib on these libs, but my expectation was that the boost build / install process would produce libraries that one could link to right away)

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[signals2][review] The review of the signals2 library (formerly thread_safe_signals) begins today, Nov 1st
by Stjepan Rajko 22 Feb '09

22 Feb '09

Hello all, The review for the Signals2 library (formerly known as thread_safe_signals) submitted by Frank Mori Hess begins today (Nov 1st) and is scheduled to end on Nov 10th. I would like to thank Franz Alt, Terry Golubiewski, Doug Gregor, Ravikiran Rajagopal and Andrew Webber for making this review possible by committing to reviewing the library. How to submit a review: -------- As usual, EVERYONE is welcome to participate in the review discussions and to submit a review. I strongly encourage participation from reviewers that would examine the library from a purely user standpoint (commenting on the interface and / or the documentation), as well as reviewers that would be willing to look into the details of the implementation (i.e., you don't have to focus on both). Here are some questions you might want to answer in your review (feel free to skip those that don't apply to your analysis): * 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? And finally, every review should answer this question: * Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. Please submit your review either to the list or privately to me by the end of the review period. If you send me a review privately I will forward it to the list so the review can be discussed. If you would prefer me to forward your review anonymously (with your name removed) please indicate that in your e-mail. If you are a first time reviewer, here is some more information to get you started: * http://www.boost.org/community/reviews.html has more information on the review process * the review officially takes place on both the boost dev and boost-user lists, but typically more of the discussion happens on the boost dev list * if you want to get a feel for past reviews, you can find them in the archives (see http://www.boost.org/community/groups.html) - the past review dates are on the review schedule (http://www.boost.org/community/review_schedule.html) Typically, there is a period of discussion between the reviewers and the author, with official reviews coming in towards the tail end of the review period. About the library: -------- * The library can be downloaded from: http://www.boostpro.com/vault/index.php?&directory=thread_safe_signals (latest version is signals2-2008-10-08.zip) * Documentation is also available online: http://www.comedi.org/projects/signals2/libs/signals2/doc/html/index.html * A synopsis: The Boost.Signals2 library (formerly known as thread_safe_signals) is an implementation of a managed signals and slots system. Signals represent callbacks with multiple targets, and are also called publishers or events in similar systems. Signals are connected to some set of slots, which are callback receivers (also called event targets or subscribers), which are called when the signal is "emitted." Signals and slots are managed, in that signals and slots (or, more properly, objects that occur as part of the slots) can track connections and are capable of automatically disconnecting signal/slot connections when either is destroyed. This enables the user to make signal/slot connections without expending a great effort to manage the lifetimes of those connections with regard to the lifetimes of all objects involved. When signals are connected to multiple slots, there is a question regarding the relationship between the return values of the slots and the return value of the signals. Boost.Signals2 allows the user to specify the manner in which multiple return values are combined. * Relationship to Boost.Signals: This is a thread-safe variant of the original Boost.Signals library. There have been some changes to the interface to support thread-safety, mostly with respect to automatic connection management. The following thread offers some more details on the differences between the two implementations, as well as a plan of a phased replacement of Boost.Signals should Signals2 be accepted: http://tinyurl.com/4sqau3 [nabble] The Signals2 FAQ also covers some differences: http://tinyurl.com/576gl6 Kind regards, Stjepan (review manager)

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Using boost::barrier
by Asheh 22 Feb '09

22 Feb '09

Hi, Having trouble with sleeping N threads while I need to wake them. Since boost contains no sleep/wake functionality I have tried using boost::condition, I have had trouble with this too (it seems to cause locks). Somone mentioned boost::barrier I read about it in the documentation and it appears to function in a way I would require, here is what im looking for: I reach a point in the program where I segment a pieces of data and it needs to be processed in parallel on two threads, the main thread waits for the two worker threads to finish processing then continues on, those two threads (or N threads..) must then go back to sleep until they are needed again. Can anyone provide a good solution, if boost::barrier is what im looking for could you help me describe how Id correctly impliment this? Thanks Ashley. -- View this message in context: http://www.nabble.com/Using-boost%3A%3Abarrier-tp22137821p22137821.html Sent from the Boost - Users mailing list archive at Nabble.com.

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Asio HTTP Server
by Christoph Schreiber 22 Feb '09

22 Feb '09

Hi! I'm looking for a smart way to read HTTP-Post data. Is request_handler::handle_request the right place to do this? Or should I better to use connection::handle_read? Any ideas (or even better, examples) anybody? I'm stuck. Regards, luky

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