ecore_time - Differences between time functions

This example shows the difference between calling ecore_time_get(), ecore_loop_time_get() and ecore_time_unix_get().

It initializes ecore, then sets a timer with a callback that, when called, will retrieve the system time using these 3 different functions. After displaying the time, it sleeps for 1 second, then call display the time again using the 3 functions.

Since everything occurs inside the same main loop iteration, the internal ecore time variable will not be updated, and calling ecore_loop_time_get() before and after the sleep() call will return the same result.

The two other functions will return a difference of 1 second, as expected. But ecore_time_unix_get() returns the number of seconds since 00:00:00 1st January 1970, while ecore_time_get() will return the time since a unspecified point, but that never goes back in time, even when the timezone of the machine changes.

Note

The usage of ecore_loop_time_get() should be preferred against the two other functions, for most time calculations, since it won't produce a system call to get the current time. Use ecore_time_unix_get() when you need to know the current time and date, and ecore_time_get() when you need a monotonic and more precise time than ecore_loop_time_get().

//Compile with:
// gcc -o ecore_time_functions_example ecore_time_functions_example.c `pkg-config --libs --cflags ecore`
 
#include <Ecore.h>
#include <unistd.h>
 
static Eina_Bool
_timer_cb(void *data EINA_UNUSED)
{
   printf("ecore time: %0.3f\n", ecore_time_get());
   printf("loop time: %0.3f\n", ecore_loop_time_get());
   printf("unix time: %0.3f\n", ecore_time_unix_get());
   printf("\nSleep for 1 second...\n\n");
   sleep(1);
   printf("ecore time: %0.3f\n", ecore_time_get());
   printf("loop time: %0.3f\n", ecore_loop_time_get());
   printf("unix time: %0.3f\n", ecore_time_unix_get());
 
   ecore_main_loop_quit();
 
   return EINA_FALSE;
}
 
int
main(void)
{
   if (!ecore_init())
     {
        printf("ERROR: Cannot init Ecore!\n");
        return -1;
     }
 
   ecore_timer_add(0.1, _timer_cb, NULL);
   ecore_main_loop_begin();
   ecore_shutdown();
}