cpp/chrono/c/timespec get

@1@ Modifies the std object pointed to by to hold the current calendar time in the time base. @2@ Expands to a value suitable for use as the argument of.

Other macro constants beginning with may be provided by the implementation to indicate additional time bases.

If is, then
 * is set to the number of seconds since an implementation defined epoch, truncated to a whole value,
 * member is set to the integral number of nanoseconds, rounded to the resolution of the system clock.

Return value
The value of if successful, zero otherwise.