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socket reconnection
by boost001 10 Dec '08

10 Dec '08

I have an ASIO socket server. I need to close the socket and then listen to the socket again if client disconnected from server. When the server was started, the socket and acceptor are initialized like this: asio_socketPtr = new tcp::socket(asio_service); asio_acceptorPtr = new tcp::acceptor(asio_service, tcp::endpoint(protocol, m_iPort)); in the process closing the socket, I did the following in order: asio_acceptorPtr->close(error_closing); asio_socketPtr->shutdown(tcp::socket::shutdown_both, error_closing); asio_socketPtr->close(error_closing); in the process reopen the socket, I did the following in order: asio_socketPtr->open(protocol, error_connecting); asio_acceptorPtr->open(protocol, error_connecting); but I always got error. the error code is 1. It means Operation not permitted. Did I miss something? Do I need to delete above socketPtr and acceptorPtr and create new one each time? thanks, -- View this message in context: http://www.nabble.com/socket-reconnection-tp20922241p20922241.html Sent from the Boost - Users mailing list archive at Nabble.com.

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asio - How do I modify code using old ASIO to newer version?
by Jeff Lee 10 Dec '08

10 Dec '08

Hi , I have some code using the old version of ASIO . some code like this: try { while( mWrapped->mSocket.in_avail() > 0 ) { ... but I found that there is no in_avail() method exist in current version. how can I resolve the problem ? Plz dont just give a web link. I'm using the very very slow internet connection.. so , search from internet or even get the document is difficult.

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[Asio] async_connect leaking memory/handles ?
by Jim Methley 10 Dec '08

10 Dec '08

Hello there, New to the list and using Boost Asio. I've implemented an SSL connection using async_connect ok, but find that it seems to leave resources allocated when completed and the SSL connection object is destroyed. The application using the Boost SSL functionality creates a socket connection as required then releases it. Its running on a windows platform with Microsoft Visual Studio 2008 and Boost 1.36.0. The problem can be easily illustrated by simple modification of http://www.boost.org/doc/libs/1_36_0/doc/html/boost_asio/example/ssl/cli ent.cpp to place the main functionality in a loop. Then monitoring the process using TaskManager to display Mem Usage and Handles shows both steadily going up. The number of handles increments by 1,2 or 3 on each async_connect. This happens regardless of whether it actually manages to connect or not. A modification to not use SSL has no effect. A further modification to use a synchronous connect and the program then does not bleed resources. Is this a known problem ? Or is there something which I should be releasing myself ? The actual code I tested is shown below. The relevant parts are: 1) main() line 140: while (true) 2) class client() line 32: simple socket connect (resources released ok) 3) class client() line 41: original async_connect (resources not released ok) Any ideas gratefully received ! /Jim // // client.cpp // ~~~~~~~~~~ // // Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include <cstdlib> #include <iostream> #include <boost/bind.hpp> #include <boost/asio.hpp> #include <boost/asio/ssl.hpp> using boost::asio::ip::tcp; enum { max_length = 1024 }; class client { public: client(boost::asio::io_service& io_service, boost::asio::ssl::context& context, boost::asio::ip::tcp::resolver::iterator endpoint_iterator) : simpleSocket_(io_service) ,socket_(io_service, context) { boost::asio::ip::tcp::endpoint endpoint = *endpoint_iterator; // This consumes no resources simpleSocket_.connect(endpoint); // This consumes resources // simpleSocket_.async_connect(endpoint, // boost::bind(&client::handle_connect, this, // boost::asio::placeholders::error, // ++endpoint_iterator)); // This original code consumes resources // socket_.lowest_layer().async_connect(endpoint, // boost::bind(&client::handle_connect, this, // boost::asio::placeholders::error, ++endpoint_iterator)); } void handle_connect(const boost::system::error_code& error, boost::asio::ip::tcp::resolver::iterator endpoint_iterator) { std::cout << "handled connect"; return; if (!error) { socket_.async_handshake(boost::asio::ssl::stream_base::client, boost::bind(&client::handle_handshake, this, boost::asio::placeholders::error)); } else if (endpoint_iterator != boost::asio::ip::tcp::resolver::iterator()) { socket_.lowest_layer().close(); boost::asio::ip::tcp::endpoint endpoint = *endpoint_iterator; socket_.lowest_layer().async_connect(endpoint, boost::bind(&client::handle_connect, this, boost::asio::placeholders::error, ++endpoint_iterator)); } else { std::cout << "Connect failed: " << error << "\n"; } } void handle_handshake(const boost::system::error_code& error) { if (!error) { std::cout << "Enter message: "; std::cin.getline(request_, max_length); size_t request_length = strlen(request_); boost::asio::async_write(socket_, boost::asio::buffer(request_, request_length), boost::bind(&client::handle_write, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } else { std::cout << "Handshake failed: " << error << "\n"; } } void handle_write(const boost::system::error_code& error, size_t bytes_transferred) { if (!error) { boost::asio::async_read(socket_, boost::asio::buffer(reply_, bytes_transferred), boost::bind(&client::handle_read, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } else { std::cout << "Write failed: " << error << "\n"; } } void handle_read(const boost::system::error_code& error, size_t bytes_transferred) { if (!error) { std::cout << "Reply: "; std::cout.write(reply_, bytes_transferred); std::cout << "\n"; } else { std::cout << "Read failed: " << error << "\n"; } } private: tcp::socket simpleSocket_; boost::asio::ssl::stream<boost::asio::ip::tcp::socket> socket_; char request_[max_length]; char reply_[max_length]; }; int main(int argc, char* argv[]) { try { if (argc != 3) { std::cerr << "Usage: client <host> <port>\n"; return 1; } while (true) { std::cout << "Creating service\n"; boost::asio::io_service io_service; boost::asio::ip::tcp::resolver resolver(io_service); boost::asio::ip::tcp::resolver::query query(argv[1], argv[2]); boost::asio::ip::tcp::resolver::iterator iterator = resolver.resolve(query); boost::asio::ssl::context ctx(io_service, boost::asio::ssl::context::sslv23); ctx.set_verify_mode(boost::asio::ssl::context::verify_peer); ctx.load_verify_file("ca.pem"); client c(io_service, ctx, iterator); io_service.run(); } } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "\n"; } return 0; }

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[Serialization] assertion failure on exit
by Kenny Riddile 09 Dec '08

09 Dec '08

I'm getting the following assertion failure on exit when instantiating certain serializable classes: Assertion failed: NULL != l, file libs\serialization\src\extended_type_info.cpp, line 47 I was finally able to determine a difference between the classes that caused the assertion failure and those that didn't. Here's some code: ////////////////////////////////////////////////////////////////// // Serializable.hpp: class Serializable { public: virtual ~Serializable() = 0; template< typename Archive > void serialize( Archive& /*ar*/, const unsigned int /*version*/ ) { } private: }; inline Serializable::~Serializable() { } BOOST_CLASS_EXPORT( Serializable ) ////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////// // Foo.hpp: struct Foo : Serializable { template< typename Archive > void serialize( Archive& ar, const unsigned int /*version*/ ) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP( Serializable ); } }; BOOST_CLASS_EXPORT( Foo ) ////////////////////////////////////////////////////////////////// The above code does not assert on exit after instantiating a Foo object. If I make Foo not header-only like so: ////////////////////////////////////////////////////////////////// // Foo.hpp: struct Foo : Serializable { Foo(); template< typename Archive > void serialize( Archive& ar, const unsigned int /*version*/ ) { ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP( Serializable ); } }; BOOST_CLASS_EXPORT( Foo ) ////////////////////////////////////////////////////////////////// ////////////////////////////////////////////////////////////////// // Foo.cpp: Foo::Foo() { } ////////////////////////////////////////////////////////////////// then I get the assertion failure on program exit if I so much as instantiate a Foo object.

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asio - how to reuse existing socket descriptor?
by QPlace 09 Dec '08

09 Dec '08

I am porting Win32 C++ application to use boost asio library. In this application I have a client socket that is returned to me from the call to 3-rd party library. Then I am getting data from the connection using WSAAsyncSelect, where the first parameter is the socket handle. My question: Is there any way to use asio library to read data from already established connection where I know the client socket handle? I cannot initiate connection myself, it is only done through 3-rd party library, I only know client socket descriptor. Any help/comments will be greatly appreciated.

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why does subversion checkout refer only to 1.34?
by Robert P. J. Day 09 Dec '08

09 Dec '08

i checked out the svn trunk for boost and, while i read that the latest version of boost is 1.37, the README.txt file refers only to 1.34.0. can someone clarify this? thanks. rday -- ======================================================================== Robert P. J. Day Linux Consulting, Training and Annoying Kernel Pedantry: Have classroom, will lecture. http://crashcourse.ca Waterloo, Ontario, CANADA ========================================================================

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asio::deadline_timer::expires_at problem when system time changes
by Jeff Gray 09 Dec '08

09 Dec '08

My application is running on an embedded system that has no battery backed up real time clock. So when it starts, it's always 1-1-1970. The first time a client app connects, it synchronizes the time, so the system time will change to 2008. This has drastic consequences on this sort of action: void MyClass::TimerCallback(void) { // do important periodic activity here... myTimer->expires_at(myTimer->expires_at()+ boost::posix_time::milliseconds(100)); myTimer->async_wait(boost::bind(&MyClass::TimerCallback, this)); } Since the expires_at() values is absolute time, it still thinks it's 1970, moving forward 100mS at a time. This causes the timer to expire immediately, and my CPU load goes to 100% as it gets stuck in this repetition. This is not a bug on the part of deadline_timer - it's doing exactly what I told it to. The question is how should I change the code to cope with time changes. I see several options: 1) The API call to set the time on my embedded device is within my application, so I know when an outside party has changed the time. I could send a boost::signal to the rest of the application & wrote code in each module that has a deadline timer used in this way that resets the timer. 2) Before setting a new expires_at value, I could calculate the time period between now() and expires_at(). If it is more than double the periodic delay, then I use expires_from_now() to resync with the new absolute time. 3) I could calculate the periodic time based on absolute time: now() - (now() % milliseconds(100)) + milliseconds(100) This means it would always be aligned with the most recent 100mS time. 4) Only use expires_from_now(). This is the simplest solution, but there are parts of my application where it is preferable to have more accurate timer period. These approaches all have advantages and drawbacks. Does anyone have any comments or experience with this issue? Thanks, Jeff

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Re: [Boost-users] [boost] [review][constrained_value] Review of ConstrainedValueLibrary begins today
by Jesse Perla 09 Dec '08

09 Dec '08

I wasn't sure if anyone was allowed to review, but if so, then all of my questions have been answered: Library Review: > > - What is your evaluation of the design? I can't comment on it as a generic library designer, but as a library user it appears to be an excellent framework. However, the use cases for bounds checking of variables are much more thought through than the more interesting mathematics/set theory and numerics use cases. I think the library seems to be close to supporting these use cases but needs to explicitly address: 1) Floating Points: Enough has been said about this, but it needs to be resolved before the library is completed. Otherwise, all mathematics/numerics use cases are impossible. As a pragmatist about this issue, I would say that a worst case "solution" is to write caveats in the "rationale" section about this problem when using this library. This library is useful for querying bounds on a type, even if it doesn't do any bounds checking. 2) Dynamic Bounded Types: Right now the static bounds are associated globally with a type, and the dynamic bounds are associated with an instance of a type. Since many use cases involve setting dynamic sets and then creating instances, it is crucial that this type of set is implemented. See Robert's rough notes in: http://lists.boost.org/boost-users/2008/12/42959.php 3) Representing Disjoint Sets: Because most of the use cases have been thinking about predicates and bounds checking, the key use cases of unions of bounds has not been addressed. In most of the discussions, people talk about layering constraints on top of each other, which is an intersection. This library needs to also have ways to easily create sets like: (-infinity, 0] union [1,2] union [3,infinity) This would be a union of constraints which could be set or accessed on the type (at runtime or compiletime), hopefully with simple iterators to access this type information. I think that thinking through closed/open/halfopen/etc. intervals as separate objects in themselves is critical, especially to layer this type of bound on. Perhaps it could be integrated with the interval template library in the sandbox for example. 4) Testing with Numerics: This library needs to be tested with key boost numeric packages such as ublas, boost math, accumulators, etc. The key here will also be to verify that it compiles with the static and dynamic bounded types, the storage is identical to the underlying type, and the operations it generates are not any slower. Also that all of the elementary operators on intrinsic types in C++ work as normal for by value/ref/pointer, numeric_limits is thought through, etc. All of the former is performance/storage testing would be conditional on a good compiler of course (gnu and Intel seem to be the main ones to worry about) > - What is your evaluation of the implementation? For the existing constraint types, it looks good. > - What is your evaluation of the documentation? Good for the simple cases here and the bounds checking. Incomplete for the key math/numerics use cases which is where this would be at its best. And the floating point section would need to be rewritten after it is "solved". > - What is your evaluation of the potential usefulness of the library? Extraordinarily useful for generic mathematics/numerics. Even without any bounds checking, managing subsets of intrinsic types with runtime bounds information has a huge value. And having domains/ranges associated with functions would save a huge number of bugs in numeric processing, as well as make the translation from blackboard to program much more elegant. This could be a cornerstone of allowing for safe implementations of mathematical models in disciplines such as economics. For example, an optimizer operating on bounded values could create a grid from just the passed in type, validate if a solution is converging to an open set bound, etc. And higher order functors such as derivatives could generate domain/range information for the functions they are operating on dynamically. > - Did you try to use the library? With what compiler? Did you have any > problems? No. It doesn't yet have the main constraint type I am interested in. > - How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? I had previously been writing notes on a library to manage domain/range information for functors that this becomes a superset of, so I have thought through a large number of those use cases. A great deal of time was spent trying to see how this library could fit the use cases I am interested in. > - Are you knowledgeable about the problem domain? > For generic library design: little knowledge. For the bounds-checking, value monitoring use cases: little knowledge. For the mathematics/numerics use cases: A good deal of knowledge as I am working through many of these issues in projects/research and trying to build out domain specific libraries to make future research easier.. > Please state in your review, whether you think the library should be > accepted as a Boost library. Yes, conditional on solving the 1) to 4) design questions above. Robert has posted excellent starting points for many of these topics.

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[random]how to initialise a rng for use in the initialiser list?
by Moritz Beber 09 Dec '08

09 Dec '08

Hello again, sorry for the many questions to this list right now, I'm just beginning to use boost. This time I have some issues regarding the boost.random usage. I have used it just fine for many examples but there's one tricky bit that I was wondering whether anyone of you knows a solution for. I use a class which keeps the random number generator around as a member variable; this class also has a const matrix. Now in the constructor of the class I do something like: my_class::my_class(args) : rng(seed), matrix(initialise()), ... { ... } Of course, I want to use the rng to initialise the matrix and that's where things fail. I guess, I could use a different rng just to fill the matrix, or make it non-const and fill it in the constructor body. But does anyone know a neat trick to do this in the way proposed? Thank you for any answers, Moritz

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boost asio async_read_som
by Chris Freehill 08 Dec '08

08 Dec '08

Never mind... I finally realized io_service.run() exits if there is no work to do. I was misunderstood and thought it stayed running. Thanks, Chris -- =======================

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