title: Is there an equivalent to the rewind function, but for one token only?
body: <p>In the C language, the rewind function is used to set the position of a stream to the very beginning. I'd like to ask if there's an equivalent function that moves the stream position to the left by one token only.</p>
  
  <p>For example, I have a file called FooFile.txt that contains several lines of sequences of integers separated by a " " whitespace character.</p>
  
  <pre><code>int main()
  {
      // open file stream.
      FILE *FooFile = fopen("FooFile.txt" , "r");
      int Bar = 0;
  
      // loop through every integer token in the file stream.
      while ( fscanf( FooFile, "%d", &amp;Bar ) == 0 )
      {
          // I don't want to reset the stream to the very beginning.
          // rewind( FooFile );
          // I only need to move the stream back one token.
  
          Bar = fscanf ( FooFile, "%d", &amp;Bar )
          Bar = fscanf ( FooFile, "%d", &amp;Bar )
      }
  }
  </code></pre>