set-visited-file-modtime

set-visited-file-modtime is a built-in function in `C source code'.

(set-visited-file-modtime &optional TIME-FLAG)

Update buffer's recorded modification time from the visited file's time.
Useful if the buffer was not read from the file normally
or if the file itself has been changed for some known benign reason.
An argument specifies the modification time value to use
(instead of that of the visited file), in the form of a list
(HIGH LOW USEC PSEC) or an integer flag as returned by
`visited-file-modtime'.