c - C / Linux - 如何使用套接字连接和读取邮件服务器（如 gmail 或 Outlook）的答案？

Question

我想连接到邮件服务器来阅读邮件。比如我有一个outlook地址toto@outlook.com，我想获取这个邮箱的所有邮件，并且能够阅读。所以我相信我只需要做一个客户端，但是：我如何联系和连接到这种类型的服务器，我如何听取答案？

这是我当前的客户端代码：

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>

int     main()
{
  struct protoent       *pe;
  int                   fd_client;
  struct sockaddr_in    s_in;
  int                   port;
  char                  *ip;
  char                  buff[4096];

  ip = strdup("157.56.242.251"); // I get it while calling "ping outlook.com"
  port = 210;
  pe = getprotobyname("TCP");
  fd_client = socket(AF_INET, SOCK_STREAM, pe->p_proto);
  s_in.sin_family = AF_INET;
  s_in.sin_port = htons(port);
  s_in.sin_addr.s_addr = inet_addr(ip);
  if (connect(fd_client, (struct sockaddr *)&s_in, sizeof(s_in)) == -1)
    {
      if (close(fd_client) == -1)
        return (-1);
      fprintf(stderr, "Failed to connect\n");
      return (-1);
    }

   //From here I don't know what to do, so I tried this
   recv(fd_client, buff, 4096, 0);
   printf("%s\n",buff);
   write(fd_client, "Hello !\n", strlen("Hello !\n"));
   //To Here

  if (close(fd_client) == -1)
    return (-1);
  return (0);
}

提前致谢。