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| <h4 class="subsection">12.10.1 What Unreading Means</h4> |
| |
| <p>Here is a pictorial explanation of unreading. Suppose you have a |
| stream reading a file that contains just six characters, the letters |
| ‘<samp><span class="samp">foobar</span></samp>’. Suppose you have read three characters so far. The |
| situation looks like this: |
| |
| <pre class="smallexample"> f o o b a r |
| ^ |
| </pre> |
| <p class="noindent">so the next input character will be ‘<samp><span class="samp">b</span></samp>’. |
| |
| <!-- @group Invalid outside @example --> |
| <p>If instead of reading ‘<samp><span class="samp">b</span></samp>’ you unread the letter ‘<samp><span class="samp">o</span></samp>’, you get a |
| situation like this: |
| |
| <pre class="smallexample"> f o o b a r |
| | |
| o-- |
| ^ |
| </pre> |
| <p class="noindent">so that the next input characters will be ‘<samp><span class="samp">o</span></samp>’ and ‘<samp><span class="samp">b</span></samp>’. |
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| <p>If you unread ‘<samp><span class="samp">9</span></samp>’ instead of ‘<samp><span class="samp">o</span></samp>’, you get this situation: |
| |
| <pre class="smallexample"> f o o b a r |
| | |
| 9-- |
| ^ |
| </pre> |
| <p class="noindent">so that the next input characters will be ‘<samp><span class="samp">9</span></samp>’ and ‘<samp><span class="samp">b</span></samp>’. |
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