把标准输出重定向到一个网络连接

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

int main(int argc, char* argv[])
{
    if (argc <= 2)
    {
        printf("usage: %s ip_address port_number\n", basename(argv[0]));
        return 1;
    }
    const char* ip = argv[1];
    int port = atoi(argv[2]);

    struct sockaddr_in address = {0};
    address.sin_family = AF_INET;
    inet_pton(AF_INET, ip, &address.sin_addr);
    address.sin_port = htons(port);

    int sock = socket(PF_INET, SOCK_STREAM, 0);
    assert(sock >= 0);

    int ret = bind(sock, (struct sockaddr*)&address, sizeof(address));
    assert(ret != -1);

    ret = listen(sock, 5);
    assert(ret != -1);

    struct sockaddr_in client;
    socklen_t client_addrlength = sizeof(client);
    int connfd = accept(sock, (struct sockaddr*)&client, &client_addrlength);
    if (connfd < 0)
    {
        printf("errno is: %d\n", errno);
    }
    else
    {
        // 关闭标准文件输入
        close(STDOUT_FILENO);

        // 把标准输出重定向到一个网络连接
        dup(connfd);
        printf("abcd\n");
        close(connfd);
    }

    close(sock);
    return 0;
}