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Network sockets using QT s require the addition of a sentence in the. pro file: QT       += network   I. Client 1. The client code is slightly simpler than the server. Generally speaking, using the QTcpSocket class in the QT to communicate with the server requires only the following five steps: (1) Create a QTcpSocke ...

String connection misuse Wrong Writing: String s = ""; for (Person p : persons) { s += ", " + p.getName(); } s = s.substring(2); //remove first comma Correct writing: StringBuilder sb = new StringBuilder(persons.size() * 16); // well estimated buffer for (Person p : persons) { if (sb.length() > 0) sb.append(", "); sb.app ...

Preface In this article, we will introduce the development of server, and explore how to develop a high performance and concurrent server program from many aspects. It should be noted that the complexity of large servers lies in their business, not in the basic framework of their code engineering. Large servers generally consist of mult ...

Introduction to udp udp - User Datagram Protocol is a simple connectionless datagram-oriented transport layer protocol. udp does not provide reliability; it simply sends datagrams from applications to the IP layer, but it does not guarantee that they will reach their destinations. udp does not need to establish a connection between client a ...

Download Mysql I use 64-bit MySQL 5.7.20 to execute the following commands wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.20-linux-glibc2.12-x86_64.tar.gz Encounter problems 1,wget commond not found If you sign up for wget commond not found ation, you have not installed wget configuration for centos. This command needs to b ...

1. Exchange two digits in situ Python provides an intuitive way to assign and exchange (variable values) in a single line of code. See the following example: x,y= 10,20 print(x,y) x,y= y,x print(x,y) #1 (10, 20) #2 (20, 10) A new tuple is formed on the right side of the assignment and unpack on the left side to the variables < a > and & ...

Installation of common packages # yum -y install coreutils glib2 lrzsz mpstat dstat sysstat e4fsprogs xfsprogs ntp readline-devel zlib-devel openssl-devel pam-devel libxml2-devel libxslt-devel python-devel tcl-devel gcc make smartmontools flex bison perl-devel perl-ExtUtils* openldap-devel jadetex openjade bzip2 Configuring OS Kernel Parame ...

brief introduction WebSocket: It is a network communication protocol. Servers can actively push information to clients, and clients can also actively send information to servers. details sockjs-client: js library, which can simulate support for WebSocket if the browser does not support WebSocket github STOMP: Simple (Streaming) Text Ori ...

I. Content Review and Supplement Brief description of three handshakes and four waves The three handshake accept accepts connections waiting for clients in the process connect client initiates a syn link request If you get the server-side response ack, you will also receive a syc link request from the server-side. After the client responds ...

What is zero copy?Let's start with a look at traditional I/O operations.Let's say that the user process now copies one file to another.Then the user program must first read this file into memory, and then write the data in memory to another file.However, file read-in memory is not directly read into the memory of user processes, but read into t ...