c++客户端如何使用ssl url连接服务器

#include <openssl/ssl.h>
#include <openssl/err.h>

int main() {
    // 初始化SSL库
    SSL_library_init();
    SSL_load_error_strings();
    OpenSSL_add_all_algorithms();

    // 创建SSL上下文
    SSL_CTX* ctx = SSL_CTX_new(SSLv23_client_method());

    // 加载证书和私钥
    SSL_CTX_use_certificate_file(ctx, "client.crt", SSL_FILETYPE_PEM);
    SSL_CTX_use_PrivateKey_file(ctx, "client.key", SSL_FILETYPE_PEM);

    // 创建SSL连接
    SSL* ssl = SSL_new(ctx);

    // 设置服务器主机名和端口
    const char* hostname = "example.com";
    const int port = 443;

    // 建立SSL连接
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(port);
    server_addr.sin_addr.s_addr = inet_addr(hostname);
    connect(sockfd, (struct sockaddr*)&server_addr, sizeof(server_addr));
    SSL_set_fd(ssl, sockfd);
    SSL_connect(ssl);

    // 发送和接收数据
    SSL_write(ssl, "Hello, server!", strlen("Hello, server!"));
    char buffer[1024];
    SSL_read(ssl, buffer, sizeof(buffer));

    // 关闭SSL连接
    SSL_shutdown(ssl);
    SSL_free(ssl);
    close(sockfd);

    // 清理SSL上下文
    SSL_CTX_free(ctx);

    // 清理SSL库
    ERR_free_strings();
    EVP_cleanup();

    return 0;
}