network-programming

问题 I have been working on a java program that basically acts like Minechat(text-based app to just view chat.) I have never really worked with networking too much, so the issue is figuring out how to send packets correctly. I am currently at the position of creating the handshake with the server. After hours of research, I have come up with the following code, but it always runs into the "Failed! (Exception)" message. To me, everything looks correct, but for all I know it could be 100% wrong. If

问题 I have been working on a java program that basically acts like Minechat(text-based app to just view chat.) I have never really worked with networking too much, so the issue is figuring out how to send packets correctly. I am currently at the position of creating the handshake with the server. After hours of research, I have come up with the following code, but it always runs into the "Failed! (Exception)" message. To me, everything looks correct, but for all I know it could be 100% wrong. If

问题 when with portfowarding the websocket pass by internet and only send when the connexion is close (on my network it's like that), I first try to close the websocket by closing chrome(it worked), so now i found terminate that i think can do the same than closing the webbrowser,but it's only for the serveur that have this function and the problem is that the buffer with close is not 0 but 13... so how can i do a hard close with ws.terminate or something else to flush the buffer to 0 and a basic

问题 I want to make a ping function with Qt (and don't like the QProcess execution system ping way). Here's the demo code, void SimmplePing(const QString& sAddress, int port=80) { QTcpSocket messenger; messenger.connectToHost(sAddress, port); if (!messenger.waitForConnected(3000)) { qDebug() << messenger.error(); } else { qDebug() << "OK"; } } void test() { SimmplePing("182.34.19.222", 80); } I test it with "192.168.0.1" (my router IP) and "www.baidu.com" both can work. But I test it "182.34.19

问题 Problem Statement I am trying to make an application for Android that can detect nearby smartphone devices. I need to discover smartphone devices regardless of their connection to a WLAN or their operating system. The only requirement is that their bluetooth or wifi setting is enabled. I am trying to capture the MAC Address and maybe RSSI of these devices. An example of an application I am trying to emulate is Meshlium. Methods Already Considered Android Classic Bluetooth: I have followed the

问题 I'm writing a server/client program that clients send text message to server.I have used non-blocking I/O (NIO API) but messages on the server do not display correctly.this is my code on server: private JTextArea displayArea; private int numBytes; private ByteBuffer buffer; /*... some code is here ...*/ displayArea = new JTextArea(); add(new JScrollPane(displayArea), BorderLayout.CENTER); setSize(400, 500); setVisible(true); /*... some code is here ...*/ buffer = ByteBuffer.allocate(20);

问题 I'm trying to generate Erdos-Renyi graphs using boost graph library. In the code below, which is taken from The Boost 1.72 documentation the networks always have the same number of edges (they should not, for particular p values). I have tried using different random seeds to no avail. Thanks for any help. #include <boost/graph/adjacency_list.hpp> #include <boost/graph/erdos_renyi_generator.hpp> #include <boost/random/linear_congruential.hpp> #include <iostream> using namespace std; typedef

问题 I'm trying to generate Erdos-Renyi graphs using boost graph library. In the code below, which is taken from The Boost 1.72 documentation the networks always have the same number of edges (they should not, for particular p values). I have tried using different random seeds to no avail. Thanks for any help. #include <boost/graph/adjacency_list.hpp> #include <boost/graph/erdos_renyi_generator.hpp> #include <boost/random/linear_congruential.hpp> #include <iostream> using namespace std; typedef

问题 The following code results in a mysterious third frame: 451-["clientMsg",{"_placeholder":true,"num":0}] Cient function sendMessage() { var bufArr = new ArrayBuffer(4); var bufView = new Uint8Array(bufArr); bufView[0]=6; bufView[1]=7; bufView[2]=8; bufView[3]=9; // send binary message to server socket.emit('serverMsg', bufArr); } sendMessage(); Server socket.on('serverMsg', function (bufArr) { var ba = new ArrayBuffer(4); var bv = new Uint8Array(ba); bv[0]=10; bv[1]=11; bv[2]=12; bv[3]=13; var

问题 There are two functions in epoll: epoll_ctl epoll_wait Are they thread-safe when I use the same epoll_fd? What will happen if one thread calls epoll_wait and others call epoll_ctl at the same time? 回答1: It is thread-safe, but there isn't much documentation that explicitly states that - see http://linux.derkeiler.com/Mailing-Lists/Kernel/2006-03/msg00084.html BTW, you can also have multiple threads waiting on a single epoll_fd, but in that case it can get a bit tricky (i.e. you might want to