LED control on Pogoplug E02 (3 replies)

I'm chasing what I think should be an obvious issue, but I can't find it.

The host is a Pogoplug E02 running Debian jessie.

Logged into the system as root, the following two commands turn the green LED on and off as expected.

root@www:# echo "default-on" > "/sys/class/leds/status:green:health/trigger"
root@www:# echo "none" > "/sys/class/leds/status:green:health/trigger"

So here is a little program adapted from the one at https://github.com/suetanvil/ledflash/blob/master/ledflash.c, which to my mind should blink the green LED on and off a few times:

#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <syslog.h>
#include <string.h>
#include <sys/stat.h>

#   define FLASHFILE   "/sys/class/leds/status:green:health/trigger"
#   define ON          "default-on"
#   define OFF         "none"

void main() {
    FILE *ledfile;
    int status;

  ledfile = fopen(FLASHFILE, "w");
  if (ledfile == NULL) {
    printf("Unable to open '" FLASHFILE "' for write\n");
    printf("Error: %d (%s)\n", errno, strerror(errno));
    exit(0);
  }

  status = fputs("none", ledfile);
  sleep(1);
  status = fputs("default-on", ledfile);
  sleep(1);
  status = fputs("none", ledfile);
  sleep(1);
  status = fputs("default-on", ledfile);
  sleep(1);
  status = fputs("none", ledfile);
  sleep(1);
  status = fputs("default-on", ledfile);
  sleep(1);
  status = fputs("none", ledfile);
  sleep(1);
  status = fputs("default-on", ledfile);
  sleep(1);
  status = fputs("none", ledfile);
  sleep(1);
  status = fputs("default-on", ledfile);
  sleep(1);
  status = fputs("none", ledfile);

  exit(0);
}

The program's effect is exactly nothing. No error on the LED device file open, no blinking LED.

Does anyone see what the problem is here?