If not NULL, the length of the string is stored in the memory location to which it points.
lineno
If not NULL, the value of the memory location to which is pointed to, is incremented by the number of lines actually read from the file.
delim
Contains the escape, continuation, and comment characters. If a character is NUL then processing for that character is disabled. If NULL, all characters default to values specified below. The contents of delim is as follows:
delim[0]
The escape character, which defaults to \, is used to remove any special meaning from the next character.
delim[1]
The continuation character, which defaults to \, is used to indicate that the next line should be concatenated with the current one if this character is the last character on the current line and is not escaped.
delim[2]
The comment character, which defaults to #, if not escaped indicates the beginning of a comment that extends until the end of the current line.
flags
If non-zero, alter the operation of fparseln. The various flags, which may be or -ed together, are: