Setting and Updating Absolute Time in Zephyr Application Using time_t Epoch

Question

I am trying to configure the absolute time in my application, which at some point receives the time_t epoch value from an external source and should update it internally so that at any time I can retrieve the actual epoch to use in my application. I have tried to update the epoch using the function 
 void Set_Time( time_t epochTime )
{
 int ret;
 struct timespec ts;

 ts.tv_sec = epochTime;
 ts.tv_nsec = 0;
 ret = clock_settime( CLOCK_REALTIME, &ts );

 if ( ret < 0 )
 {
 LOG_WRN( "clock_settime returned error" );
 }
} 
 and then read it through the function time(NULL) , but the latter always returns the value -1 . Does anyone have any suggestions for implementing what I want?

Andrea Verdecchia · Accepted Answer

Thank you for your response. In the meantime, I solved the issue by no longer using the time() function, which seemed to be linked to a different library than I had expected. I believe the -1 value was due to it not being initialized. I resolved the problem by implementing custom functions that use clock_settime() and clock_gettime() . 
 void Set_Time( time_t epoch )
{
 int ret;
 struct timespec ts;

 ts.tv_sec = epoch;
 ts.tv_nsec = 0;
 ret = clock_settime( CLOCK_REALTIME, &ts );

 if ( ret < 0 )
 {
 LOG_WRN( "clock_settime returned error" );
 }
}

time_t Get_Time( void )
{
 struct timespec ts;
	int ret;

	ret = clock_gettime( CLOCK_REALTIME, &ts );

	if ( ret < 0 )
 {
 return (time_t) -1;
	}

	return ts.tv_sec;
} 
 This way, I can update and read the absolute epoch.

Setting and Updating Absolute Time in Zephyr Application Using time_t Epoch

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