c - 写入套接字退出程序

Question

我正在编写一个基本的 hello world 网络程序，但是当我在客户端调用 write 时，程序就停止了。有谁知道为什么会这样？该函数不返回任何内容:

const char* msg = "Hello World!\n";
char buffer[256];
int sockfd, n;
struct sockaddr_in srv_ip4;
struct hostent* server;

puts ("a");
sockfd = socket (AF_INET, SOCK_STREAM, 0);
if (sockfd < 0) {
    perror ("Unable to open socket");
    return false;
}

puts ("b");
server = gethostbyname (addr);
if (!server) {
    fprintf (stderr, "Unable to find host: %s\n", addr);
    return false;
}
memset (&srv_ip4, 0, sizeof (struct sockaddr_in));

puts ("c");
srv_ip4.sin_family = AF_INET;
memcpy (&srv_ip4.sin_addr.s_addr, server->h_addr, server->h_length);
srv_ip4.sin_port = htons (PORT);

puts ("d");
n = write (sockfd, msg, 13);
if (n < 0) {
    puts ("Why?");
    perror ("Unable to write to socket");
    return false;
}
memset (buffer, 0, 256);

puts ("e");
n = read (sockfd, buffer, 255);
if (n < 0) {
    perror ("Unable to read from socket");
    return false;
}
printf ("%s", buffer);

puts ("f");
close (sockfd);

return true;

输出是:

a b c d

Answer 1

你应该connect发送数据之前到服务器。

通过this article .