메뉴얼에 보면 다음과 같이 나와있습니다.
When using CTRL-X CTRL-O after a name without any "." or "->" it is completed
from the tags file directly. This works for any identifier, also function
names. If you want to complete a local variable name, which does not appear
in the tags file, use CTRL-P instead.
When using CTRL-X CTRL-O after something that has "." or "->" Vim will attempt