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Credits to Boost.Asio
by David Demelier 13 Apr '18

13 Apr '18

Hello, I'm the author of irccd [0], a C++ IRC bot extensible with plugins. Up to the 3.0.0 version current in development, I had my network code written by myself (being used of lots of poll(2) usage in C). I have switched to Boost.Asio a while ago to remove my own code and facilitate further development. Even though I think it has its learning curve, I enjoyed a lot the switch and tested my IRC bot to connect 100 times in the same instance to my own local IRC server. It took less than 2 seconds to join all requested channels, taking only 2MB of RAM. This is just awesome. Congratulations for this powerful module :) [0]: http://projects.malikania.fr/irccd -- David

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boost::rational does not maintain its invariant in case of overflow
by Frédéric 11 Apr '18

11 Apr '18

With the program shown below, I obtained the following output: std::numeric_limits<long>::max() == 9223372036854775807 r == boost::rational<long>(4294967296, 1853020188851841) == 4294967296/1853020188851841 r * r == 0/8733086111712066817 Clearly there are 2 overflows but this leads to the invariant of the class not being maintained, i.e. the faction is not simplified to 0/1 (gcd(num, den) != 1). F #include <boost/rational.hpp> #include <iostream> int main() { std::cout << "std::numeric_limits<long>::max() == " << std::numeric_limits<long>::max() << '\n'; boost::rational<long> r(4294967296, 1853020188851841); std::cout << "r == boost::rational<long>(4294967296, 1853020188851841) == " << r << '\n'; std::cout << "r * r == " << (r * r) << '\n'; return 0; }

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How do I "run the configure tests"?
by Chris Stankevitz 10 Apr '18

10 Apr '18

Can't find anything about it in the docs. "Unknown compiler version - please run the configure tests and report the results" [1] Thank you, Chris [1] From https://www.boost.org/doc/libs/1_65_1/boost/config/compiler/visualc.hpp

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Toolset version for Visual Studio 2017 15.6.3
by Chris Stankevitz 10 Apr '18

10 Apr '18

What version should I pass to b2 --toolset=msvc-x.y for "Visual Studio 2017 15.6.3"? [1] says [2] will have an up-to-date list with an answer, but [2] is not up-to-date. Thank you, Chris [1] https://www.boost.org/doc/libs/1_65_1/more/getting_started/windows.html#ide… [2] https://www.boost.org/build/doc/html/bbv2/reference/tools.html

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[asio] SSL async_shutdown() never finishes if called when async_read_some() is in progress
by Alexander D. 08 Apr '18

08 Apr '18

Hello, I'm writing a middleware which basically adds an SSL layer to the connection between a client and a server. The connection is bidirectional, so I need to read from each side and write to the other. The client can also close the connection at any time, in which case async_shutdown() must be called on the server's stream. The problem is, often the shutdown happens when the program is waiting on the server through async_read_some(), and the shutdown will never finish. The following code illustrates this issue: #include <iostream> #include <boost/asio.hpp> #include <boost/asio/ssl.hpp> int main(int argc, char* argv[]) { try { boost::asio::io_context io_context; boost::asio::streambuf buffer; boost::asio::ssl::context ctx(boost::asio::ssl::context::tlsv12); ctx.set_verify_mode(boost::asio::ssl::verify_none); boost::asio::ssl::stream<boost::asio::ip::tcp::socket> sock(io_context, ctx); sock.next_layer().connect(boost::asio::ip::tcp::endpoint( boost::asio::ip::make_address("127.0.0.1"), 4433)); sock.handshake(boost::asio::ssl::stream_base::client); /* "async_shutdown" won't appear unless async_read_some() * is commented out */ sock.async_read_some(buffer.prepare(1024), [](boost::system::error_code, size_t) {std::cout << "async_read_some" << std::endl;}); sock.async_shutdown([](boost::system::error_code) {std::cout << "async_shutdown" << std::endl;}); io_context.run(); } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "\n"; } return 0; } To reproduce, start up an SSL server: openssl genrsa -out key.pem 2048 openssl req -new -sha256 -key key.pem -out csr.csr openssl req -x509 -sha256 -days 365 -key key.pem -in csr.csr -out server.pem openssl s_server -key key.pem -cert server.pem and run the program. Notice that "async_shutdown" does not finish even if the server is killed. In practice, this leaks the memory of the shutdown handler and whatever is bound to it. The only solution I can think of would be to cancel the read operation, but there's no portable way in asio to do this. Can someone point out how to solve this? Cheers, Alexander

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[release] Boost 1.67.0 Beta 1
by Daniel James 07 Apr '18

07 Apr '18

Boost release 1.67.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.67.0.beta.1/source/> The SHA256 checksums are as follows: 154cf490da858fd9c2307bb904b07a42cbe8355ecf99d5477f0d843c6d03cdda boost_1_67_0_b1.7z 0d854b208fefaeb5837d6c417f505b189275e32d017f6226001fb165a5ac51ed boost_1_67_0_b1.tar.bz2 6eb3f9ca8db355765f41361e1e26976228f0c2dff400aade8a5e97aec6aa59f4 boost_1_67_0_b1.tar.gz 678a6459f2517932536ec97297be1de46ea073f2e2ee17ec8397b80aa0953f49 boost_1_67_0_b1.zip For details of what's in the release, see <http://www.boost.org/users/history/version_1_67_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

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Pointer Container Library changes in 1.66.0
by Kevin Hardman 06 Apr '18

06 Apr '18

I am seeing changes in the Pointer Container Library that are preventing my existing application from compile. I see no notice of changes in the 1.66.0 release notes <http://www.boost.org/users/history/version_1_66_0.html <http://www.boost.org/users/history/version_1_66_0.html>>. Is there documentation on the changes and what is required to migrate existing users to the new library? —kevin

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[log] Unable to use own severity struct encapsulated in namespace
by Sebastian Messerschmidt 06 Apr '18

06 Apr '18

Hi folks, When taking this example [1] and modifying the enum 'severity_level' like this: namespace x { struct test { enum severity_level { normal, notification, warning, error, critical }; }; } and replacing all references to severity_level with the appropriate x::test::severity_level the 'operator<<' overload for the severity_level is not issued. Can anyone help me with this one? I can supply the complete modified example if needed Cheers Sebastian [1] https://www.boost.org/doc/libs/1_58_0/libs/log/example/doc/tutorial_attribu…

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[ptr_map] Warning about returning address of local variable
by Bill Buklis 05 Apr '18

05 Apr '18

I'm not sure if this a potential bug/problem or just a benign warning, but when using the map_values range adaptor with a ptr_map container I get a warning about returning an address of a local variable. It seems benign as the expected processing happens, but this type of warning generally doesn't sound like a good thing. The following useless code will trigger it. #include <boost/ptr_container/ptr_map.hpp> #include <boost/range/algorithm.hpp> #include <boost/range/adaptors.hpp> struct sample { int value; }; typedef boost::ptr_map<int, sample> themap; int main() { themap data; int key = 5; data.insert(key, new sample); boost::for_each(data | boost::adaptors::map_values, [](sample* s) { s->value = 10; }); return 0; } I'm using Visual Studio 2017. I also have conformance mode (/permissive-) turned on for stricter language compliance in case it makes a difference. As an aside, I was a little surprised when trying out this little sample that the inclusion of the above headers is enough to require linking with the boost regex library. I figure it's probably a reference in the adaptors somewhere. It's not a big deal. These lib files are normally available anyway. -- Bill

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boost::asio::async_read_until fills streambuf less than actually received
by David Demelier 03 Apr '18

03 Apr '18

Hello, I'm using Asio to read IRC messages asynchronously from a server. I use boost::asio::async_read_until with "\r\n" as delimiter and a boost::asio::streambuf as output buffer. I mostly implemented the code like described on my original question/answer here: https://stackoverflow.com/questions/40561097/read-until-a-string-delimi ter-in-boostasiostreambuf I sometimes get the bytes_transferred argument bigger that what is filled into the buffer. My code looks like this: void connection::do_recv(handler_t handler) { boost::asio::async_read_until(socket_, buffer_, "\r\n", [this, handler] (auto code, auto xfer) { if (code || xfer == 0U) handler(std::move(code), message()); else { //assert(buffer_.size() > xfer); std::cout << "xfer: " << xfer << std::endl; std::cout << "size: " << buffer_.size() << std::endl; std::string str( boost::asio::buffers_begin(buffer_.data()), boost::asio::buffers_begin(buffer_.data()) + xfer - 2 ); buffer_.consume(xfer); handler(std::move(code), message::parse(str)); } }); } void connection::rflush() { if (input_.empty()) return; do_recv([this] (auto code, auto message) { auto h = input_.front(); // Delete first, in case of exceptions. input_.pop_front(); if (h) h(code, std::move(message)); if (!code) rflush(); }); } void connection::recv(handler_t handler) { auto in_progress = !input_.empty(); input_.push_back(std::move(handler)); if (!in_progress) rflush(); } For some reasons, after several calls, I get an assertion failure in the std::string construction. Because buffer_.size() is actually smaller than xfer. I could not understand why. Example of output: ... ... xfer: 87 size: 141 Note: I've implemented the recv() public function like what I can see for send in some tutorials. I wanted a queue of handlers so I can safely call recv() multiple times before first functions finished completely. Regards, -- David

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