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[Bimap] Iterator invalidation
by Adam Badura 25 Jun '14

25 Jun '14

What are rules for iterator invalidation in Boost.Bimap? I have looked in documentation (version 1.55) but didn't found anything. I'm particularly interested in the bimap<...>::iterator (or ::const_iterator) invalidation. But the question remains valid for any kind of iterators. Adam Badura

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Autobahn for C++: RPC and PubSub
by Tobias Oberstein 24 Jun '14

24 Jun '14

Hi, I'm happy to anounce Autobahn|Cpp - another subproject of Autobahn (http://autobahn.ws) this time for C++ 11 / Boost. Autobahn|Cpp allows remote procedure calls and publish & subscribe messaging for C++ application components and uses boost::future, continuations and Boost/ASIO as underlying network library. Here is how app code looks like: https://github.com/tavendo/AutobahnCpp/blob/master/README.md#show-me-some-c… Using Autobahn|Cpp, you can e.g. call your C++ code from JavaScript running in a browser. And much more. This is an early alpha version, things aren't fully hashed out, but there are a couple of examples included here: https://github.com/tavendo/AutobahnCpp/blob/master/README.md#examples Cheers, /Tobias

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Boost Social Event at CppCon
by Jon Kalb 24 Jun '14

24 Jun '14

Boosters, Because a lot of Boosters are going to be attending CppCon, we¹d like to arrange a social event for Boosters/C++Now regulars. http://cppcon.org/ If you are planning to attend CppCon or even If you are just going to be in or around Bellevue, Washington between September 7th and 12 and you¹d like to join us for dinner, please let us know so we can get a count. Please send mail to: social(a)boost.org Once we settle on a date, etc, we¹ll let everyone who responded know when and where, so please let us know, even if you are a ³maybe.² This year¹s CppCon program includes sessions from a number of Boosters and C++Now regulars with sessions specifically about Boost Libraries. If you are considering attending, please be aware that the Early Bird registration deadline is just days away. http://cppcon.org/registration/ If you are attending, please make your hotel reservations soon. We are likely to sell out of our room block. http://cppcon.org/lodging/ I hope to see you at CppCon. Jon

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Re: [Boost-users] [Boost.Test] BOOST_CHECK_THROW behaviour
by Ghyslain Leclerc 23 Jun '14

23 Jun '14

On 23/06/2014 17:19:01 +1200, Gavin Lambert wrote >>You could try submitting that as a bug report in Trac (if it's not already there), or waiting for Gennadiy Rozental's response. Done. I hope I did it properly. Never reported a bug on Boost before. Quoted our discussion, so that some more info is available if necessary. >>In the meantime, you'd need to write a more intelligent test yourself. I will do it manually. Found someone on Stack Overflow who wanted the same behavior I expected and did it. In case it helps someone, here is the snippet: try { … code that should throw ... BOOST_ERROR( “<function_name> did not throw anything. Expected a <exception_name>” ); } catch( <exception_name> const& ) { //ok, this is the expected case } catch(…) { BOOST_ERROR( “<function_name> has throw an unknown exception, but a <exception_name> was expected.” ); } and the reference: http://stackoverflow.com/questions/21774387/boost-unit-testing-exceptions Thanks again for your help.

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[Boost.Test] BOOST_CHECK_THROW behaviour
by Ghyslain Leclerc 23 Jun '14

23 Jun '14

Hello, Sorry for the long post! I have a simple class, which I am posting a fraction of here for discussion sake: ------------------------------------------------------ class AsciiTableRow { public: void setCol( std::size_t colIdx, std::string const& newContent ); void setCol( std::size_t colIdx, const char* newContent ); private: void checkIdxBound_( std::size_t colIdx, std::string const& msg ); std::vector< std::string > data_; bool maxColWidthIsValid_; } inline void AsciiTableRow::setCol( std::size_t colIdx, std::string const& newVal ) { checkIdxBound_( colIdx, "setCol" ); maxColWidthIsValid_ = false; data_[colIdx] = newVal; } inline void AsciiTableRow::setCol( std::size_t colIdx, const char* newContent ) { setCol( colIdx, std::string( newContent ) ); } inline void AsciiTableRow::checkIdxBound_( std::size_t colIdx, std::string const& msg ) { if( colIdx > data_.size() ) { throw std::out_of_range( "AsciiTableRow::" + msg + " : colIdx out of range" ); } } ------------------------------------------------------ The code above should be sufficient for the discussion and I don’t think any other code is relevant. Should you need to see my constructor and destructor, nothing is virtual so I just copy every value and set some defaults. Nothing fancy, but I will gladly post the code if need be. What I do then is try and devise a test to see if the exception is indeed thrown and if it is the correct one. Here is the code I use: AsciiTableRow testRow; // empty, so any index will throw BOOST_CHECK_THROW( testRow.setCol( 30, 12 ), std::out_of_range ); BOOST_CHECK_THROW( testRow.setCol( 30, 12l ), std::out_of_range ); This works fine. Then, I had the idea to check what the behaviour would be if the wrong exception is thrown. I simply changed the first call like this : BOOST_CHECK_THROW( testRow.setCol( 30, 12 ), std::runtime_error ); BOOST_CHECK_THROW( testRow.setCol( 30, 12l ), std::out_of_range ); I was under the impression (and I might be wrong here, sorry :-( ) that the Boost.Test library would (the numbers are not to mean that order, simply there for enumeration): 1- output a message saying the test has failed, that an exception was indeed thrown, but it was not a runtime_error 2- continue the rest of the test (single test currently) 3- terminate but I actually never get the message of step 1, the execution of the rest of the test seems never occur (the second BOOST_CHECK_THROW) and the program terminate because of my exception and not very gracefully. I guess my questions to the other users here are: - Was my understanding of what BOOST_CHECK_THROW does flawed ? - Is the behaviour normal ? - Is there an obvious problem I am missing with the design of my simple class ? In case it is useful, I am on OSX 10.9. I have compiled boost myself (sources of version 1.55 downloaded from the Boost site). I compile my work with C++11 enabled. I am using GCC 4.7 installed via Macports. Anyhow, any insight will be appreciated. As everyone is busy, thanks in advance to anybody for any time spent on this. Ghyslain

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[asio] Closing async client socket after writing last message
by Nicholas Yue 23 Jun '14

23 Jun '14

Hi, I have adapted the chat tutorial example to send messages to a similar (chat tutorial based) server. It is currently working fine however due to the async_write(), I can't close the socket until after all the pending data has been processed on the server end. I have google and found discussion and mentioned about async_write() completion handler calling socket.close() however, I was not able to find specific detail as to how that is done. I want to avoid closing the connection prematurely as it is asynchronous writing. My current do_write() looks like this void DisplayChatClient::do_write(DisplayChatMessage msg) { DLOG(INFO) << "DisplayChatClient::do_write()"; bool write_in_progress = !write_msgs_.empty(); write_msgs_.push_back(msg); if (!write_in_progress) { boost::asio::async_write(socket_, boost::asio::buffer(write_msgs_.front().data(), write_msgs_.front().length()), boost::bind(&DisplayChatClient::handle_write, this, boost::asio::placeholders::error)); } } void DisplayChatClient::handle_write(const boost::system::error_code& error) { DLOG(INFO) << "DisplayChatClient::handle_write()"; if (!error) { write_msgs_.pop_front(); if (!write_msgs_.empty()) { boost::asio::async_write(socket_, boost::asio::buffer(write_msgs_.front().data(), write_msgs_.front().length()), boost::bind(&DisplayChatClient::handle_write, this, boost::asio::placeholders::error)); } } else { do_close(); } } Cheers -- Nicholas Yue Graphics - Arnold, Alembic, RenderMan, OpenGL, HDF5 Custom Dev - C++ porting, OSX, Linux, Windows http://au.linkedin.com/in/nicholasyue https://vimeo.com/channels/naiadtools

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Boost Filesystem fails with FreeBSD 10, clang, and boost
by Ricky Huang 21 Jun '14

21 Jun '14

Hello all, I am currently migrating to a FreeBSD 10 system which comes default with clang language. I was able to compile Boost just fine. But when I include filesysstem.hpp to it, I get the following error message: > Linking CXX executable boost_clang_test > /usr/bin/ld: : invalid DSO for symbol `_ZN5boost6system15system_categoryEv' definition > /usr/local/lib/libboost_system.so.1.55.0: could not read symbols: Bad value > CC: error: linker command failed with exit code 1 (use -v to see invocation) > *** Error code 1 > > Stop. I am using cmake as my build system, could it be possible that I need to adjust my cmake variables? I am not sure if I've came to correct forum or should this be on FreeBSD, clang, CMake forum(s)? Please let me know if I am at the wrong place… The minimum amount of code to induce the problem are the following 2 files: CMakeLists.txt: cmake_minimum_required(VERSION 2.8) # Find and include Boost libraries find_package(Boost 1.55 COMPONENTS filesystem REQUIRED) include_directories(${Boost_INCLUDE_DIR}) set(LIBS ${LIBS} ${Boost_LIBRARIES}) set(BOOST_CLANG_TEST_SOURCES ${SOURCES} main.cpp) add_executable(boost_clang_test ${BOOST_CLANG_TEST_SOURCES}) target_link_libraries(boost_clang_test ${LIBS}) main.cpp: #include <stdio.h> #include <iostream> #include <sstream> #include <string> #include <boost/filesystem.hpp> using namespace std; using namespace boost::filesystem; const char *progname; int main(int argc, char **argv){ return 0; } Thanks in advance.

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[graph] kamada_kawai_spring_layout warnings
by Michael Olea 21 Jun '14

21 Jun '14

Hi. I'm getting compiler warnings for subscripts out of range from kamada_kawai_spring_layout.hpp. I'm using boost_55_0, compiled with clang: Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn) Target: x86_64-apple-darwin13.2.0 Thread model: posix ../../../../../include/boost/graph/kamada_kawai_spring_layout.hpp:110:49: warning: array index 2 is past the end of the array (which contains 2 elements) [-Warray-bounds] double denom = mat[0][0] * (mat[1][1] * mat[2][2] - mat[2][1] * mat[1][2]) The offending code is: template <> struct linear_solver<3> { template <typename Vec> static Vec solve(double mat[2][2], Vec rhs) { double denom = mat[0][0] * (mat[1][1] * mat[2][2] - mat[2][1] * mat[1][2]) - mat[1][0] * (mat[0][1] * mat[2][2] - mat[2][1] * mat[0][2]) + mat[2][0] * (mat[0][1] * mat[1][2] - mat[1][1] * mat[0][2]); double x_num = rhs[0] * (mat[1][1] * mat[2][2] - mat[2][1] * mat[1][2]) - rhs[1] * (mat[0][1] * mat[2][2] - mat[2][1] * mat[0][2]) + rhs[2] * (mat[0][1] * mat[1][2] - mat[1][1] * mat[0][2]); double y_num = mat[0][0] * (rhs[1] * mat[2][2] - rhs[2] * mat[1][2]) - mat[1][0] * (rhs[0] * mat[2][2] - rhs[2] * mat[0][2]) + mat[2][0] * (rhs[0] * mat[1][2] - rhs[1] * mat[0][2]); double z_num = mat[0][0] * (mat[1][1] * rhs[2] - mat[2][1] * rhs[1] ) - mat[1][0] * (mat[0][1] * rhs[2] - mat[2][1] * rhs[0] ) + mat[2][0] * (mat[0][1] * rhs[1] - mat[1][1] * rhs[0] ); Vec result; result[0] = x_num / denom; result[1] = y_num / denom; result[2] = z_num / denom; return result; } }; Looks like it should be: static Vec solve(double mat[3][3], Vec rhs) ... No?

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stack unwinding with boost::fcontext
by David Frank 20 Jun '14

20 Jun '14

Context - 1.53.0 beta1 Context - 1.53.0 beta1 Context Struct fcontext_t and related functions Each instance of fcontext_t represents a context (CPU registers and stack space). View on www.boost.org Preview by Yahoo I'm wondering if there is any example showing how to do stack unwinding as described at the bottom of the above link as quoted below: " Stack unwinding Sometimes it is necessary to unwind the stack of an unfinished context to destroy local stack variables so they can release allocated resources (RAII pattern). The user is responsible for this task. " Thanks, Frank

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[coroutine] await_emu example
by bbxiong 20 Jun '14

20 Jun '14

Hi, coroutine listers! The example is very awesome. but after reading though the source, i have a question: Is any limitation makes a push_coroutine must be caller and pull_coroutine must be the coro? This way, we have to yield out at the first line of coroutine function by calling caller(), just like the example showed: typedef coroutines::pull_coroutine<void> coro_pull; typedef coroutines::pull_coroutine<void> coro_push; auto asynchronous(F f) -> future<decltype(f())> { typedef promise<decltype(f())> CoroPromise; CoroPromise coro_promise; auto coro_future = coro_promise.get_future(); CurrentCoro current_coro = { make_shared<coro_pull>(std::bind([f](CoroPromise &coro_promise, coro_push &caller) { caller(); coro_stack.top().caller = &caller; coro_promise.set_value(f()); }, std::move(coro_promise), placeholders::_1); }; coro_stack.push(std::move(current_coro)); (*coro_stack.top().coro)(); coro_stack.pop(); return coro_future; } There is an extra call to caller() in coroutine function to jump out to prepare coro stack. Why not swap coro_pull and coro_push like this: auto asynchronous(F f) -> future<decltype(f())> { typedef promise<decltype(f())> CoroPromise; CoroPromise coro_promise; auto coro_future = coro_promise.get_future(); CurrentCoro current_coro = { make_shared<coro_push>(std::bind([f](CoroPromise &coro_promise, coro_pull &caller) { coro_stack.top().caller = &caller; coro_promise.set_value(f()); }, std::move(coro_promise), placeholders::_1); }; coro_stack.push(std::move(current_coro)); (*coro_stack.top().coro)(); coro_stack.pop(); return coro_future; } This still works on my machine, and has no extra "call to caller()", push_coroutine is not invoked until we explicitly run it (while pull_coroutine is invoked in constructor). So, my question is, s there any bad effects by using coroutines in this way? Thanks in advance!

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