boost-asio | 易学教程

boost asio buffer lazy allocation

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问题 Async operations. Now I pass preallocated byte buffer, for example: s.async_receive_from( boost::asio::buffer( preallocated_pointer, preallocated_size ), _remote_endpoint, boost::bind(...) ); Is it possible to make lazy allocation for this and other calls? 回答1: Lazy allocation, or allocating when the resource is needed, can be accomplished using boost::asio::null_buffers. null_buffers can be used to obtain reactor-style operations within Boost.Asio. This can be useful for integrating with

C++ multiple multicast receiver with boost asio

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I have to implement a multicast receiver able to join a list of multicast groups and process received data in a specific thread using boost. I did try the following code..... boost::asio::io_service m_io_service; boost::asio::ip::udp::socket m_multicast_socket(m_io_service); // listen address boost::asio::ip::address listen_address = boost::asio::ip::address::from_string("0.0.0.0"); // listen port unsigned short multicast_port = m_configuration->m_multicast_interface_port; boost::asio::ip::udp::endpoint listen_endpoint( listen_address, multicast_port ); // open socket m_multicast_socket.open(

Socket I/O mode epoll,overlapped I/O

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I am working client server application where I need to manage multiple socket connection 1000+. By exploration I found out the Overlapped I/O or Completion Port is nice to do de-multiplexing multiple socket in Windows and epoll is nice on Linux. Is epoll is different from Overlapped I/O or Completion Port in windows. I wanted to use boost since it works on both windows and Linux. Is it possible to implement these techniques (epoll and Overlapped I/O or Completion Port) using boost? The implementation of epoll on Linux and I/O completion ports on Windows are different, however Boost.Asio nicely

boost.asio linking and libraries

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I'm new to boost.asio programming and i have difficulties linking boost libraries. My question is that how to find out which libraries I should link to my project when I include asio headers. For example I used #include <boost/date_time/posix_time/posix_time.hpp> and #include <boost/asio.hpp directives. so this is my command to compile it: g++ -I /usr/local/boost_1_55_0 ASIO.cpp -o HELLO -L /usr/local/lib/ -l boost_system consider my boost library is installed on /usr/local/boost_1_55_0 and binaries are on /usr/local/lib. my problem is actually what I need to write after -l Thanks for your

HTTP Client Request Response with pion-net c++

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I want to create a simple HTTPClient with pion-net (Pion-net leverages boost::asio.). Boot Version 1.49 Pion-net Version 4.11 My client should just be a able to: send a HTTP Request (this is working) receive the HTTP Response (not working) asynchronous code is not a must, synchronous would be ok This is what I got: #include <iostream> #include "boost/asio.hpp" #include "boost/thread.hpp" #include "pion/net/HTTPRequestWriter.hpp" #include "pion/net/HTTPResponseReader.hpp" void FinishedResponseReading(pion::net::HTTPResponsePtr httpResponsePtr, pion::net::TCPConnectionPtr tcpConnectionPtr, const

Boost SSL verifies expired and self-signed certificates

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I'm using Boost's asio to connect to a site via HTTPS. I want this to only succeed if the certificate is valid, not expired, not self-signed, etc. Unfortunately it seems to always work regardless. Here is my code: try { asio::io_service ioService; asio::ssl::context sslContext(asio::ssl::context::sslv3_client); sslContext.load_verify_file("cacert.pem"); asio::ip::tcp::resolver resolver(ioService); asio::ip::tcp::resolver::query query("self-signed.badssl.com", "443"); asio::ip::tcp::resolver::iterator endpointIterator = resolver.resolve(query); boost::asio::ssl::stream<boost::asio::ip::tcp:

Is it safe to use spawn directly in an asio stackful coroutine?

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When I use spawn to start a new stackfull coroutine in a coroutine, valgrind says a lot of using uninitialised value( valgrind output ). Then I use io_service.post to invoke a handler,and start a new stackfull coroutine in it, every thing seems fine. I have searched and read some documents, but can't find something about how to create a new stackfull coroutine safely in a stackfull coroutine. Here is the code: #include <iostream> #include <boost/asio.hpp> #include <boost/asio/spawn.hpp> #include <boost/asio/system_timer.hpp> #include <chrono> using namespace std; int main() { auto use_post =

boost::asio::socket thread safety

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问题 ( This is a simplified version of my original question ) I have several threads that write to a boost asio socket. This seems to work very well, with no problems. The documentation says a shared socket is not thread safe( here, way down at the bottom ) so I am wondering if I should protect the socket with mutex, or something. This question insists that protection is necessary, but gives no advice on how to do so. All the answers to my original question also insisted that what I was doing

using boost sockets, do I need only one io_service?

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问题 having several connections in several different threads.. I'm basically doing a base class that uses boost/asio.hpp and the tcp stuff there.. now i was reading this: http://www.boost.org/doc/libs/1_44_0/doc/html/boost_asio/tutorial/tutdaytime1.html it says that "All programs that use asio need to have at least one io_service object." so should my base class has a static io_service (which means there will be only 1 for all the program and a all the different threads and connections will use

boost::asio::io_service occupied queue lengths for timers and posts

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问题 I'm fairly new to boost::asio, but I'm working on a project that has already existed for a few years and uses asio extensively. My current assignment is to add periodic metrics about various things the system is doing. One of the metrics is to observe how deep the boost::asio::io_service work queues and timer queues become at an arbitrary period of runtime. So I need to be able to ask a boost:asio::io_service object how many things it has in its queues. To illustrate what I'm asking, consider