time, uptime - get time
#include <sys/types.h>
#include <time.h>
Callable from ISR.
time() returns the value of time in seconds since the Epoch (00:00:00 UTC, January 1, 1970).
uptime() returns the value of time in seconds since the system start-up time.
If tloc is non-zero, the return value is also stored in the location to which tloc points.
Upon successful completion, functions return the value of time. Otherwise, a value of (time_t)-1 is returned.
No errors are defined.
These functions fail and its actions are undefined if tloc points to an illegal address.
uptime() is not POSIX function.