c语言怎么实现websocket

在C语言中实现WebSocket，你可以使用libwebsockets库

1. 首先，确保你已经安装了libwebsockets库。如果没有，请访问官方网站（https://libwebsockets.org/）获取安装说明。对于大多数Linux发行版，你可以使用包管理器（如apt或yum）安装libwebsockets。例如，在Ubuntu上，运行以下命令：

sudo apt-get install libwebsockets-dev

2. 创建一个名为websocket_example.c的新C文件，并添加以下代码：

#include
#include 
#include
#include 

static int callback_example(struct lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len) {
    switch (reason) {
        case LWS_CALLBACK_ESTABLISHED:
            printf("Connection established\n");
            break;
        case LWS_CALLBACK_RECEIVE:
            printf("Received message: %.*s\n", (int)len, (char *)in);
            break;
        case LWS_CALLBACK_CLOSED:
            printf("Connection closed\n");
            break;
        default:
            break;
    }
    return 0;
}

static struct lws_protocols protocols[] = {
    {"example-protocol", callback_example, 0, 0},
    {NULL, NULL, 0, 0}
};

int main(void) {
    struct lws_context_creation_info info;
    struct lws_context *context;
    const char *p;
    int logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE
        /* for LLL_ verbosity above NOTICE to be built into lws,
         * lws must have been configured and built with
         * -DCMAKE_BUILD_TYPE=DEBUG instead of =RELEASE */
        /* | LLL_INFO */ /* | LLL_PARSER */ /* | LLL_HEADER */
        /* | LLL_EXT */ /* | LLL_CLIENT */ /* | LLL_LATENCY */
        /* | LLL_DEBUG */;

    lws_set_log_level(logs, NULL);

    memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
    info.port = CONTEXT_PORT_NO_LISTEN; /* we do not run any server */
    info.protocols = protocols;
    /*
     * since we know this lws context is only ever going to be used with
     * one client wsis / fds / sockets at a time, let lws know it doesn't
     * have to use the default allocations for fd tables up to ulimit -n.
     * It will just allocate for 1 internal and 1 (+ 1 http2 nwsi) that
     * we will use.
     */
    info.fd_limit_per_thread = 1 + 1 + 1;

    context = lws_create_context(&info);
    if (!context) {
        lwsl_err("lws init failed\n");
        return 1;
    }

    while (1) {
        lws_service(context, 50);
    }

    lws_context_destroy(context);

    return 0;
}

3. 编译并运行示例代码：

gcc websocket_example.c -o websocket_example -lwebsockets
./websocket_example

4. 使用WebSocket客户端（如websocat）连接到你的WebSocket服务器，并发送消息。你应该会看到连接建立、接收到的消息和连接关闭的日志。

这只是一个简单的示例，展示了如何使用libwebsockets库在C语言中实现WebSocket。你可以根据需要修改代码以满足你的需求。更多关于libwebsockets库的信息和示例，请参阅官方文档（https://libwebsockets.org/git/libwebsockets/tree/README.md?h=main）。