防止poll监听被中断

 
int common_poll(struct pollfd *pfd, int *nsds, int timeout)
{
        int nfd;
        time_t tin;
        time_t tout;
        
        if (timeout > 0) 
                tin = time(NULL);    
        
        do{
                nfd = poll(pfd, EVENTS, timeout);
                if((rv < 0) && (errno == EINTR) && (timeout > 0)){
                        tout = time(NULL);
                        if(tout - tin >= timeout/1000){
                                nfd= 0;
                                break;
                        }else{
                                timeout -= (tout - tin)*1000;
                                tin = tout;
                                continue;
                        }
                }
        }while((nfd < 0) && (errno == EINTR));
        (*nsds) = nfd;
        if ((*nsds) < 0) {
                return errno;
        }
        return 0;
}