newline-cache-check

newline-cache-check is a built-in function in `C source code'.

(newline-cache-check &optional BUFFER)

Check the newline cache of BUFFER against buffer contents.

BUFFER defaults to the current buffer.

Value is an array of 2 sub-arrays of buffer positions for newlines,
the first based on the cache, the second based on actually scanning
the buffer. If the buffer doesn't have a cache, the value is nil.