linux串口非阻塞

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>

int main() {
    int fd;
    char buffer[256];

    // 打开串口设备
    fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY);
    if (fd == -1) {
        perror("open");
        exit(EXIT_FAILURE);
    }

    // 设置非阻塞模式
    int flags = fcntl(fd, F_GETFL, 0);
    fcntl(fd, F_SETFL, flags | O_NONBLOCK);

    while (1) {
        // 尝试读取数据
        int n = read(fd, buffer, sizeof(buffer));
        if (n > 0) {
            printf("Received data: %.*s\n", n, buffer);
        } else if (n == -1 && errno != EAGAIN) {
            perror("read");
            break;
        }

        // 尝试写入数据
        const char *msg = "Hello, World!\n";
        int written = write(fd, msg, strlen(msg));
        if (written == -1 && errno != EAGAIN) {
            perror("write");
            break;
        }

        // 等待一段时间
        usleep(100000); // 100ms
    }

    // 关闭串口设备
    close(fd);

    return 0;
}