The ftime() function, introduced in V7 Unix (1979), gets the current
time in seconds and milliseconds, and time zone information.  It was
marked as a legacy interface in POSIX.1-2001, and removed altogether
from POSIX.1-2008.  The gettimeofday() function, originally from
4.1 BSD, gets the current time in seconds and microseconds, and optional
time zone information, and was marked as obsolete in POSIX.1-2008
although it was kept in the standard.  The POSIX recommended function
for getting time with sub-second resolution is clock_gettime(), which
was introduced in POSIX.1b-1993 and is now part of the base POSIX
standard; it supports multiple clocks and nanosecond resolution.
Additionally the function timespec_get() was introduced in C11 and also
supports nanosecond resolution.

To support dates beyond the year 2038, glibc and other libraries are
being updated to support 64-bit time_t even on 32-bit architectures,
requiring new implementations of interfaces that w...