#include <unistd.h>
#include <netdb.h>
int main(int argc,char *argv[])
{
struct servent serv;
struct servent *serv_info=&serv;
serv_info=getservbyport(htons(atoi(argv[1])),NULL);/*第二个参数为协议类型,为NULL时自动匹配所有协议*/
printf("%s\n%d\n",serv_info->s_name,ntohs(serv_info->s_port));
serv_info=getservbyport(htons(atoi(argv[1])),"tcp");
printf("%s\n%d\n",serv_info->s_name,ntohs(serv_info->s_port));
return 0;
}