To clarifying my request:
I like to make use of the "extra" time functions in the AVR-libc library (not contained in TimeLib.h)
as described in: https://www.arduino.cc/en/Tutorial/UsingAVRlibraries
excerpt: "Because Arduino already links It links against AVR Libc (the AVR libraries),
it is easy to use them. To use a libc library only the header needs to be included..."
for instance I like to use the function "sun_rise (const time_t *timer)"
(obtaining a ntp timestamp already solved)
for a list of time.h lib's see:
avr-libc: Modules darin u.A. <time.h>
and within time.h see:
http://www.nongnu.org/avr-libc/user-manual/group__avr__time.html
you will find the modules for calculating time of sunrise at a spcific location:
sun_rise (const time_t *timer), time_t
sun_set (const time_t *timer)
set_zone (int32_t)
set_position (int32_t latitude int32_t longitude) etc
What a stone age man know how to do (-> Stonehenge) I can't without help from arduino community.
So I'm asking for an simple AVR-libc time.h example.
As a newbee I'm not so familar useing / decoding the doxygen documentation
nor are the examples helpfull to me
Thank you for any hint and your patience