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| <h4 class="subsection">D.14.6 Console I/O</h4> |
| |
| <p><a name="index-console-i_002fo-as-part-of-file_002di_002fo-2502"></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 <RET>. 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 ‘<samp><span class="samp">Ctrl-D</span></samp>’) 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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