SIGPIPE信号

 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <unistd.h>
 #include <errno.h>
 #include <signal.h>

 #include <string.h>
 #include <assert.h>
 #include <iostream>

 void signal_func(int sig)
 {
     int saved_errno = errno;
     std::cout << "broken pipe!" << std::endl;
     errno = saved_errno;
 }

 int main()
 {
     struct sigaction sa;
     sa.sa_handler = signal_func;

     sigemptyset(&sa.sa_mask);
     sa.sa_flags = ;

     if (sigaction(SIGPIPE, &sa, NULL) < )
     {
         perror("cannot ignore SIGPIPE");

         return -;
     }

     int sockfd = socket(AF_INET, SOCK_STREAM, );
     uint16_t port = ;
     const char* ip= "192.168.16.105";

     assert(sockfd > );

     struct sockaddr_in sock_address;
     memset(&sock_address, , sizeof(sock_address));

     sock_address.sin_family = AF_INET;
     sock_address.sin_port = htons();
     inet_pton(AF_INET, ip, &(sock_address.sin_addr));

     socklen_t sock_len = sizeof(sock_address);

     int ret = connect(sockfd, (sockaddr*)&sock_address, sock_len);
     assert(ret != -);

     sleep(); // 在sleep之前断开服务端连接

     char send_buff[] = "hello server!";
     char recv_buff[] = {};

     ssize_t ret_1 = send(sockfd, send_buff, strlen(send_buff), ); // 收到对端FIN后依然可以发送成功　不过对端会响应RST

     if (ret_1 < )
     {
         std::cout << strerror(errno) << std::endl;
     }
     else
     {
         std::cout << "send success!" << std::endl;
     }

     ssize_t ret_2 = recv(sockfd, recv_buff, sizeof(recv_buff), );

     if(ret_2 == )
     {
         std::cout << "remote close connection" << std::endl;
     }

     ssize_t ret_3 = send(sockfd, send_buff, strlen(send_buff), ); // 这时再send会出错　并产生SIGPIPE信号　默认终止进程

     if(ret_3 < )
     {
         if (errno == EPIPE)
         {
             std::cout << strerror(errno) << std::endl;
         }
     }
     else
     {
         std::cout << "send success" << std::endl;
     }

     return ;
 }