select函数实现聊天
时间: 2023-08-23 20:12:25 浏览: 108
采用select的互聊
select函数可以用于实现聊天功能。在使用select函数之前,需要创建一个套接字并将其绑定到一个地址上。然后,可以使用select函数来监视套接字是否有可读数据。以下是一个简单的示例代码:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#define MAX_CLIENTS 10
#define BUFFER_SIZE 1024
int main() {
int serverSocket, clientSocket, maxSocket, activity, i, valread, sd;
struct sockaddr_in serverAddress;
fd_set readfds;
char buffer\[BUFFER_SIZE\] = {0};
// 创建套接字
serverSocket = socket(AF_INET, SOCK_STREAM, 0);
if (serverSocket == -1) {
perror("socket creation failed");
exit(EXIT_FAILURE);
}
// 设置服务器地址
serverAddress.sin_family = AF_INET;
serverAddress.sin_addr.s_addr = INADDR_ANY;
serverAddress.sin_port = htons(8888);
// 绑定套接字到地址
if (bind(serverSocket, (struct sockaddr *)&serverAddress, sizeof(serverAddress)) < 0) {
perror("bind failed");
exit(EXIT_FAILURE);
}
// 监听连接
if (listen(serverSocket, MAX_CLIENTS) < 0) {
perror("listen failed");
exit(EXIT_FAILURE);
}
// 接受连接并进行聊天
while (1) {
FD_ZERO(&readfds);
FD_SET(serverSocket, &readfds);
maxSocket = serverSocket;
// 添加已连接的客户端套接字到集合中
for (i = 0; i < MAX_CLIENTS; i++) {
sd = clientSockets\[i\];
if (sd > 0) {
FD_SET(sd, &readfds);
}
if (sd > maxSocket) {
maxSocket = sd;
}
}
// 使用select函数监视套接字
activity = select(maxSocket + 1, &readfds, NULL, NULL, NULL);
if ((activity < 0) && (errno != EINTR)) {
perror("select error");
}
// 如果有新的连接请求
if (FD_ISSET(serverSocket, &readfds)) {
if ((clientSocket = accept(serverSocket, (struct sockaddr *)&clientAddress, (socklen_t*)&addressLength)) < 0) {
perror("accept failed");
exit(EXIT_FAILURE);
}
// 将新的连接添加到客户端套接字数组中
for (i = 0; i < MAX_CLIENTS; i++) {
if (clientSockets\[i\] == 0) {
clientSockets\[i\] = clientSocket;
break;
}
}
}
// 处理客户端的消息
for (i = 0; i < MAX_CLIENTS; i++) {
sd = clientSockets\[i\];
if (FD_ISSET(sd, &readfds)) {
valread = read(sd, buffer, BUFFER_SIZE);
if (valread == 0) {
// 客户端断开连接
close(sd);
clientSockets\[i\] = 0;
} else {
// 处理客户端发送的消息
// ...
}
}
}
}
return 0;
}
```
在上述代码中,我们使用select函数来监视服务器套接字和已连接的客户端套接字。当有新的连接请求时,我们使用accept函数接受连接,并将新的客户端套接字添加到客户端套接字数组中。然后,我们使用read函数读取客户端发送的消息,并进行相应的处理。
请注意,上述代码只是一个简单的示例,实际的聊天功能可能需要更多的处理和逻辑。
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