linux 串口select

#include <sys/select.h>

int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout);

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/select.h>
#include <errno.h>
#include <termios.h>

int main(int argc, char **argv)
{
    int fd;
    int n;
    int result;
    struct termios tty;
    struct timeval tv;
    fd_set readfds;

    if (argc != 2) {
        fprintf(stderr, "Usage: %s /dev/ttyS0\n", argv[0]);
        return 1;
    }

    fd = open(argv[1], O_RDWR | O_NOCTTY | O_NDELAY);
    if (fd == -1) {
        perror("open_port: Unable to open port");
        return 1;
    }

    // 获取当前终端属性
    tcgetattr(fd, &tty);
    // 设置为原始模式
    cfmakeraw(&tty);
    tcsetattr(fd, TCSANOW, &tty);

    tv.tv_sec = 10;  // 等待10秒
    tv.tv_usec = 0;

    while (1) {
        FD_ZERO(&readfds);
        FD_SET(fd, &readfds);

        // 清空stdin
        fseek(stdin, 0L, SEEK_END);

        result = select(fd + 1, &readfds, NULL, NULL, &tv);
        if (result == -1) {
            perror("select");
            break;
        } else {
            if (FD_ISSET(fd, &readfds)) {
                char buf[256];
                n = read(fd, buf, sizeof(buf));
                if (n < 0) {
                    perror("read");
                    break;
                } else {
                    printf("Received data: %s\n", buf);
                }
            }
        }
    }

    close(fd);
    return 0;
}