Driver-tutorial/select_poll/poll1.c

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <stdlib.h>

int main(){
    int fd1, fd2;
    struct pollfd pollarray[10];
    char buf[10];
    int n;
    
    fd1 = open("./pone", O_RDWR);
    fd2 = open("./ptwo", O_RDWR);
    pollarray[0].fd = fd1;
    pollarray[1].fd = fd2;
    pollarray[0].events = POLLIN;
    pollarray[1].events = POLLIN;

    n = poll(pollarray, 2, 10000);
    if(n < 0){
        perror("poll:");
        exit(1);
    }

    //test whether fd1 is ready or not
    if( (pollarray[0].revents & POLLIN)){
        printf(" reading from fd1 (pone)\n");
        n = read(fd1, buf, 10);
        printf(" read data = %s from pone\n", buf);
    }


    //test whether fd2 is ready or not
    if( (pollarray[1].revents & POLLIN)){
        printf(" reading from fd2 (ptwo)\n");
        n = read(fd2, buf, 10);
        printf(" read data = %s from ptwo\n", buf);
    }

    // close(fd1);
    // close(fd2);
    return 0;
}