This source file includes following definitions.
- main
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15 #include <errno.h>
16 #include <fcntl.h>
17 #include <poll.h>
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <string.h>
21 #include <time.h>
22 #include <unistd.h>
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24 #include <linux/uleds.h>
25
26 int main(int argc, char const *argv[])
27 {
28 int fd, ret;
29 char brightness_file_path[LED_MAX_NAME_SIZE + 11];
30 struct pollfd pollfd;
31 struct timespec ts;
32 char buf[11];
33
34 if (argc != 2) {
35 fprintf(stderr, "Requires <device-name> argument\n");
36 return 1;
37 }
38
39 snprintf(brightness_file_path, LED_MAX_NAME_SIZE,
40 "/sys/class/leds/%s/brightness_hw_changed", argv[1]);
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42 fd = open(brightness_file_path, O_RDONLY);
43 if (fd == -1) {
44 printf("Failed to open %s file\n", brightness_file_path);
45 return 1;
46 }
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53 read(fd, buf, sizeof(buf));
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55 pollfd.fd = fd;
56 pollfd.events = POLLPRI;
57
58 while (1) {
59 ret = poll(&pollfd, 1, -1);
60 if (ret == -1) {
61 printf("Failed to poll %s file (%d)\n",
62 brightness_file_path, ret);
63 ret = 1;
64 break;
65 }
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67 clock_gettime(CLOCK_MONOTONIC, &ts);
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69 ret = read(fd, buf, sizeof(buf));
70 if (ret < 0)
71 break;
72
73 ret = lseek(pollfd.fd, 0, SEEK_SET);
74 if (ret < 0) {
75 printf("lseek failed (%d)\n", ret);
76 break;
77 }
78
79 printf("[%ld.%09ld] %d\n", ts.tv_sec, ts.tv_nsec, atoi(buf));
80 }
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82 close(fd);
83
84 return ret;
85 }