Errata
Page 45
the program listed is nonsense - its been pasted in from the Python edition.
The correct program is:
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
int main(int argc, char **argv)
{
int fd = open("/sys/class/leds/ACT/trigger", O_WRONLY);
write(fd, "timer", 5);
close(fd);
fd = open("/sys/class/leds/ACT/delay_on", O_WRONLY);
write(fd, "2000", 4);
close(fd);
fd = open("/sys/class/leds/ACT/delay_off", O_WRONLY);
write(fd, "3000", 4);
close(fd);
}