linux connect阻塞

#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char **argv)
{
    int sockfd;
    int result;
    struct sockaddr_in serv_addr;
    socklen_t length;

    if (argc != 3) {
        fprintf(stderr, "Usage: %s<ip> <port>
", argv[0]);
        exit(1);
    }

    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        perror("socket");
        exit(1);
    }

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(atoi(argv[2]));

    if (inet_pton(AF_INET, argv[1], &serv_addr.sin_addr) <= 0) {
        perror("inet_pton");
        exit(1);
    }

    // 设置超时
    struct timeval tv;
    tv.tv_sec = 5; // 5秒超时
    tv.tv_usec = 0;
    setsockopt(sockfd, SOL_SOCKET, SO_SNDTIMEO, (const char*)&tv, sizeof tv);

    result = connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
    if (result < 0) {
        perror("connect");
        exit(1);
    }

    printf("Connected successfully!
");

    close(sockfd);
    return 0;
}