FS

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

main(){
    int fd;
    char *leds = "/dev/leds";
    char *test1 = "/bin/test1";
    char *test2 = "/bin/test2";

    if((fd = open(leds,O_RDWR|O_NOCTTY|O_NDELAY))<0){
        printf("open %s failed!\n",leds);
    }
        printf("\n%s fd is %d\n",leds,fd);

    if((fd = open(test1,O_RDWR,0777))<0){
        printf("open %s failed!\n",test1);
    }
        printf("%s fd is %d\n",test1,fd);

    if((fd = open(test2,O_RDWR|O_CREAT,0777))<0){
        printf("open %s failed!\n",test2);
    }
        printf("%s fd is %d\n",test2,fd);
}

// 标准输入输出头文件
#include <stdio.h>

// 文件操作函数头文件
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

main()
{
    int fd;
    // 开发板中已经存在/dev/leds文件
    char *leds = "/dev/leds";
    // 开发板中不存在的文件/bin/test1
    char *test1 = "/bin/test1";
    // 开发板中不存在的文件/bin/test2
    char *test2 = "/bin/test2";
    // 需要新建的文件/bin/test3
    char *test3 = "/bin/test3";

    // 使用open函数打开文件
    if ((fd = open(leds, O_RDWR | O_NOCTTY | O_NDELAY)) < 0)
    {
        printf("open %s failed\n", leds);
    }
    printf("%s fd is %d\n", leds, fd);
    // 使用open函数打开不存在的文件，不添加O_CREAT标识符，会报错
    if ((fd = open(test1, O_RDWR)) < 0)
    {
        printf("open %s failed\n", test1);
    }
    // 打开文件创建文件，添加标志位O_CREAT表示不存在这个文件则创建文件
    if ((fd = open(test2, O_RDWR | O_CREAT, 0777)) < 0)
    {
        printf("open %s failed\n", test2);
    }
    printf("%s fd is %d\n", test2, fd);

    fd = creat(test3, 0777);
    if (fd = -1)
    {
        printf("%s fd is %d\n", test3, fd);
    }
    else
    {
        printf("create %s is succeed\n", test3);
    }
}

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

main()
{
    int fd;
    char *testwrite = "/bin/testwrite";
    ssize_t length_w;
    char buffer_write[] = "Hello Write Function!";

    if ((fd = open(testwrite, O_RDWR | O_CREAT, 0777)) < 0)
    {
        printf("open %s failed\n", testwrite);
    }

    length_w = write(fd, buffer_write, strlen(buffer_write));
    if (length_w == -1)
    {
        perror("write");
    }
    else
    {
        printf("Write Function OK!\n");
    }
    close(fd);
}

// 标准输入输出头文件
#include <stdio.h>

// 文件操作函数头文件
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

#define MAX_SIZE 1000

main()
{
    int fd;
    ssize_t length_w, length_r = MAX_SIZE, ret;
    char *testwrite = "/bin/testwrite";
    char buffer_write[] = "Hello Write Function!";
    char buffer_read[MAX_SIZE];

    if ((fd = open(testwrite, O_RDWR | O_CREAT, 0777)) < 0)
    {
        printf("open %s failed!\n", testwrite);
    }
    length_w = write(fd, buffer_write, strlen(buffer_write));
    if (length_w == -1)
    {
        perror("write");
    }
    else
    {
        printf("Write Function OK!\n");
    }
    close(fd);

    if ((fd = open(testwrite, O_RDWR | O_CREAT, 0777)) < 0)
    {
        printf("open %s failed!\n", testwrite);
    }
    if (ret = read(fd, buffer_read, length_r))
    {
        perror("read");
    }
    printf("Files Content is %s \n", buffer_read);
    close(fd);
}

#include <stdio.h>
#include <string.h>

// argument count变元计数
// argument value变元值
int main(int argc, char *argv[])
{
    int i, j;
    i = atoi(argv[1]);
    j = atoi(argv[2]);

    printf("the Program name is %s\n", argv[0]);

    printf("The command line has %d argument:\n", argc - 1);

    printf("%d,%d\n", i, j);

    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define LED_NUM 2
#define LED_C 2
// cmd为0，则灭，为1，则亮；
// io为0则是靠近蜂鸣器的小灯，为1则靠近独立按键的小灯
int main(int argc, char *argv[])
{
    int fd, led_num, led_c;
    char *leds = "/dev/leds";

    led_num = LED_NUM;
    led_c = LED_C;

    printf("argv1 is cmd;argv2 is io \n");
    // 对传入的参数进行判断，超出范围直接退出
    if (atoi(argv[1]) >= led_c)
    {
        printf("argv1 is 0 or 1）");
        exit(1);
    }
    if (atoi(argv[2]) >= led_num)
    {
        printf("argv2 is 0 or 1）");
        exit(1);
    }
    // 使用ioctl函数将参数传入内核
    if ((fd = open(leds, O_RDWR | O_NOCTTY | O_NDELAY)) < 0)
        printf("open %s failed\n", leds);
    else
    {
        ioctl(fd, atoi(argv[1]), atoi(argv[2]));
        printf("ioctl %s success\n", leds);
    }
    close(fd);

    return (1);
}

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>

#define BUZZER_C 2
int main(int argc, char *argv[])
{
    char *buzzer_ctl = "/dev/buzzer_ctl";
    int fd, ret, buzzer_c;

    buzzer_c = BUZZER_C;

    if (atoi(argv[1]) >= buzzer_c)
    {
        printf("argv[1] is 0 or 1\n");
        exit(1);
    }

    if ((fd = open(buzzer_ctl, O_RDWR | O_NOCTTY | O_NDELAY)) < 0)
    {
        printf("open %s failed\n", buzzer_ctl);
        exit(1);
    }

    ret = ioctl(fd, atoi(argv[1]), atoi(argv[2]));
    close(fd);

    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <stdint.h>
#include <termios.h>
// #include <android/log.h>
// #include <sys/ioctl.h>

int main(void)
{
    int fd;
    char *adc = "/dev/adc";
    char buffer[512];
    int len = 0, r = 0;

    memset(buffer, 0, sizeof(buffer));
    printf("adc ready!\n");

    if ((fd = open(adc, O_RDWR | O_NOCTTY | O_NDELAY)) < 0)
        printf("open adc err!\n");
    else
    {
        printf("open adc success!\n");

        len = read(fd, buffer, 10);

        if (len == 0)
            printf("return null\n");
        else
        {
            r = atoi(buffer);
            r = (int)(r * 10000 / 4095); // Datas  transition to Res
            printf("res value is %d\n", r);
        }
    }
}

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

#include <fcntl.h>

int main(int argc, char *argv[])
{
    struct stat groupstat;
    int fd, ret;

    if (argc < 2)
    {
        printf("\nPlease input file path\n");
        return 1;
    }

    ret = stat(argv[1], &groupstat);
    if (ret)
    {
        printf("Please make sure file path\n");
        return 1;
    }
    printf("stat function test , %s of st_ino inode is %ld\n", argv[1], groupstat.st_ino);

    fd = open(argv[1], O_RDWR | O_NOCTTY | O_NDELAY);
    if (fd < 0)
    {
        printf("Please make sure file path\n");
        return 1;
    }
    ret = fstat(fd, &groupstat);
    if (ret)
    {
        printf("Please make sure file path\n");
        return 1;
    }
    printf("fstat function test , %s of st_ino inode is %ld\n", argv[1], groupstat.st_ino);

    ret = lstat(argv[1], &groupstat);
    if (ret)
    {
        printf("Please make sure file path\n");
        return 1;
    }
    printf("lstat function test , %s of st_ino inode is %ld\n", argv[1], groupstat.st_ino);

    return 0;
}