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 = 0;

    if (sigaction(SIGPIPE, &sa, NULL) < 0)
    {
        perror("cannot ignore SIGPIPE");

        return -1;
    }

    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    uint16_t port = 7888;
    const char* ip= "192.168.16.105";

    assert(sockfd > 0);

    struct sockaddr_in sock_address;
    memset(&sock_address, 0, sizeof(sock_address));

    sock_address.sin_family = AF_INET;
    sock_address.sin_port = htons(7888);
    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 != -1);

    sleep(10); // 在sleep之前断开服务端连接

    char send_buff[1024] = "hello server!";
    char recv_buff[1024] = {0};

    ssize_t ret_1 = send(sockfd, send_buff, strlen(send_buff), 0); // 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 < 0)
    {
        std::cout << strerror(errno) << std::endl;
    }
    else
    {
        std::cout << "send success!" << std::endl;
    }

    ssize_t ret_2 = recv(sockfd, recv_buff, sizeof(recv_buff), 0);

    if(ret_2 == 0)
    {
        std::cout << "remote close connection" << std::endl;
    }

    ssize_t ret_3 = send(sockfd, send_buff, strlen(send_buff), 0); // 这时再send会出错　并产生SIGPIPE信号　默认终止进程

    if(ret_3 < 0)
    {
        if (errno == EPIPE)
        {
            std::cout << strerror(errno) << std::endl;
        }
    }
    else
    {
        std::cout << "send success" << std::endl;
    }

    return 0;
}