在C語言中搭建WebSocket服務器需要使用一些庫來處理WebSocket協議的握手和數據傳輸。以下是一個簡單的示例代碼來搭建一個WebSocket服務器：

1. 使用libwebsockets庫來創建WebSocket服務器。首先需要安裝libwebsockets庫：

git clone https://github.com/warmcat/libwebsockets.git
cd libwebsockets
mkdir build
cd build
cmake ..
make
sudo make install

2. 編寫一個簡單的WebSocket服務器代碼：

#include <libwebsockets.h>
#include <stdio.h>

int callback_http(struct lws* wsi, enum lws_callback_reasons reason, void* user, void* in, size_t len) {
    switch (reason) {
        case LWS_CALLBACK_HTTP:
            lws_return_http_status(wsi, HTTP_STATUS_OK, NULL);
            lws_return_http_body(wsi, "Hello, World!", 13);
            break;
        default:
            break;
    }
    return 0;
}

static struct lws_protocols protocols[] = {
    {
        "http-only",
        callback_http,
        0,
    },
    { NULL, NULL, 0, 0 }
};

int main() {
    struct lws_context_creation_info info;
    memset(&info, 0, sizeof(info));

    struct lws_context* context = lws_create_context(&info);

    struct lws_vhost* vhost = lws_create_vhost(context, &info);

    struct lws_http_mount mount;
    memset(&mount, 0, sizeof(mount));
    mount.mountpoint = "/";
    mount.origin = "./";
    mount.protocol = "http-only";
    mount.def = "index.html";

    lws_vhost_mount_service(vhost, &mount);

    while (true) {
        lws_service(context, 0);
    }

    lws_context_destroy(context);

    return 0;
}

3. 編譯并運行代碼：

gcc -o websocket_server websocket_server.c -lwebsockets
./websocket_server

這樣就可以在本地搭建一個簡單的WebSocket服務器了。您可以根據需要添加更多的WebSocket處理邏輯來實現更復雜的功能。