[手游项目2]-14-linux下如何用C语言编程判断某端口是否被占用

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define MAXLINE 80

int main(void)
{
	struct sockaddr_in servaddr;
	int sockfd,i,serverport,ret;
	sockfd = socket(AF_INET, SOCK_STREAM, 0);

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr);
        for(i = 0;i < 65535;i++)
	{
           servaddr.sin_port = htons(i);
	   ret = connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
           if(EISCONN == ret)
           {
                 printf("端口 %d被占用",i);
           }
	  else
           {
               close(sockfd);
           } 
       }
	return 0;
}

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