c语言 libevent高并发代码
时间: 2023-08-12 19:27:56 浏览: 44
下面是一个使用 libevent 实现高并发的 C 语言代码示例:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <event2/event.h>
void on_accept(int fd, short event, void *arg);
void on_read(int fd, short event, void *arg);
void on_write(int fd, short event, void *arg);
int main(int argc, char **argv) {
struct event_base *base;
struct event *listener_event;
struct sockaddr_in sin;
int listener_fd;
int reuseaddr_on = 1;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
sin.sin_port = htons(8080);
base = event_base_new();
if (!base) {
printf("Error: could not initialize libevent!\n");
return EXIT_FAILURE;
}
listener_fd = socket(AF_INET, SOCK_STREAM, 0);
if (listener_fd < 0) {
printf("Error: could not create socket!\n");
return EXIT_FAILURE;
}
if (setsockopt(listener_fd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr_on, sizeof(reuseaddr_on)) == -1) {
printf("Error: could not set SO_REUSEADDR!\n");
return EXIT_FAILURE;
}
if (bind(listener_fd, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
printf("Error: could not bind socket!\n");
return EXIT_FAILURE;
}
if (listen(listener_fd, SOMAXCONN) < 0) {
printf("Error: could not listen on socket!\n");
return EXIT_FAILURE;
}
listener_event = event_new(base, listener_fd, EV_READ | EV_PERSIST, on_accept, (void *)base);
event_add(listener_event, NULL);
event_base_dispatch(base);
return EXIT_SUCCESS;
}
void on_accept(int fd, short event, void *arg) {
struct event_base *base = (struct event_base *)arg;
struct sockaddr_in sin;
socklen_t slen = sizeof(sin);
int client_fd;
struct event *client_event;
client_fd = accept(fd, (struct sockaddr *)&sin, &slen);
if (client_fd < 0) {
printf("Error: could not accept connection!\n");
return;
}
printf("Accepted connection from %s:%d\n", inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
client_event = event_new(base, client_fd, EV_READ | EV_PERSIST, on_read, NULL);
event_add(client_event, NULL);
}
void on_read(int fd, short event, void *arg) {
char buffer[1024];
int nread;
nread = recv(fd, buffer, sizeof(buffer), 0);
if (nread < 0) {
printf("Error: could not read from socket!\n");
return;
}
if (nread == 0) {
printf("Closing connection...\n");
close(fd);
event_del((struct event *)arg);
event_free((struct event *)arg);
return;
}
printf("Received %d bytes: %.*s\n", nread, nread, buffer);
struct event *write_event = event_new((struct event_base *)arg, fd, EV_WRITE, on_write, NULL);
event_add(write_event, NULL);
}
void on_write(int fd, short event, void *arg) {
const char *response = "HTTP/1.1 200 OK\r\nContent-Length: 19\r\n\r\nHello, World!\r\n";
int nwritten;
nwritten = send(fd, response, strlen(response), 0);
if (nwritten < 0) {
printf("Error: could not write to socket!\n");
return;
}
printf("Sent %d bytes: %s", nwritten, response);
close(fd);
event_del((struct event *)arg);
event_free((struct event *)arg);
}
```
这个示例程序创建了一个基于 libevent 的 TCP 服务器,它监听端口 8080,并使用 `on_accept` 回调函数处理新连接。当有新的客户端连接时,该程序会创建一个新的事件,使用 `on_read` 回调函数处理该客户端的读事件。当客户端有数据可读时,该程序会读取数据并使用 `on_write` 回调函数发送响应。注意,这个简单的示例程序没有进行任何请求解析和错误处理,仅仅是一个简单的回显服务器。