Node:Unreading Idea, Next:How Unread, Up:Unreading
Here is a pictorial explanation of unreading. Suppose you have a
stream reading a file that contains just six characters, the letters
foobar
. Suppose you have read three characters so far. The
situation looks like this:
f o o b a r ^so the next input character will be
b
.
If instead of reading b
you unread the letter o
, you get a
situation like this:
f o o b a r | o-- ^so that the next input characters will be
o
and b
.
If you unread 9
instead of o
, you get this situation:
f o o b a r | 9-- ^so that the next input characters will be
9
and b
.