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<h4 class="subsection">E.13.6 Console I/O</h4>

<p><a name="index-console-i_002fo-as-part-of-file_002di_002fo-3602"></a>
By default and if not explicitly closed by the target system, the file
descriptors 0, 1 and 2 are connected to the <span class="sc">gdb</span> console.  Output
on the <span class="sc">gdb</span> console is handled as any other file output operation
(<code>write(1, ...)</code> or <code>write(2, ...)</code>).  Console input is handled
by <span class="sc">gdb</span> so that after the target read request from file descriptor
0 all following typing is buffered until either one of the following
conditions is met:

     <ul>
<li>The user types <kbd>Ctrl-c</kbd>.  The behaviour is as explained above, and the
<code>read</code>
system call is treated as finished.

     <li>The user presses &lt;RET&gt;.  This is treated as end of input with a trailing
newline.

     <li>The user types <kbd>Ctrl-d</kbd>.  This is treated as end of input.  No trailing
character (neither newline nor &lsquo;<samp><span class="samp">Ctrl-D</span></samp>&rsquo;) is appended to the input.

   </ul>

   <p>If the user has typed more characters than fit in the buffer given to
the <code>read</code> call, the trailing characters are buffered in <span class="sc">gdb</span> until
either another <code>read(0, ...)</code> is requested by the target, or debugging
is stopped at the user's request.

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