iv_invalidate_now (3) - Linux Manuals
iv_invalidate_now: ivykis time handling
NAMEiv_now, iv_validate_now, iv_invalidate_now - ivykis time handling
DESCRIPTIONiv_now is a global variable that reflects the current time-of-day. Applications written to the ivykis API generally require to know the current time-of-day in many places, and therefore effort is done to cache this quantity.
The contents of iv_now might be stale. Calling the function iv_validate_now ensures that the current contents of iv_now are up-to-date.