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Next: <a href="List-of-Supported-Calls.html#List-of-Supported-Calls" accesskey="n" rel="next">List of Supported Calls</a>, Previous: <a href="The-Ctrl_002dC-Message.html#The-Ctrl_002dC-Message" accesskey="p" rel="previous">The Ctrl-C Message</a>, Up: <a href="File_002dI_002fO-Remote-Protocol-Extension.html#File_002dI_002fO-Remote-Protocol-Extension" accesskey="u" rel="up">File-I/O Remote Protocol Extension</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Console-I_002fO-1"></a>
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<h4 class="subsection">E.13.6 Console I/O</h4>
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<a name="index-console-i_002fo-as-part-of-file_002di_002fo"></a>
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<p>By default and if not explicitly closed by the target system, the file
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descriptors 0, 1 and 2 are connected to the <small>GDB</small> console. Output
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on the <small>GDB</small> console is handled as any other file output operation
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(<code>write(1, …)</code> or <code>write(2, …)</code>). Console input is handled
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by <small>GDB</small> so that after the target read request from file descriptor
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0 all following typing is buffered until either one of the following
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conditions is met:
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</p>
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<ul>
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<li> The user types <kbd>Ctrl-c</kbd>. The behaviour is as explained above, and the
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<code>read</code>
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system call is treated as finished.
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</li><li> The user presses <tt class="key">RET</tt>. This is treated as end of input with a trailing
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newline.
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</li><li> The user types <kbd>Ctrl-d</kbd>. This is treated as end of input. No trailing
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character (neither newline nor ‘<samp>Ctrl-D</samp>’) is appended to the input.
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</li></ul>
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<p>If the user has typed more characters than fit in the buffer given to
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the <code>read</code> call, the trailing characters are buffered in <small>GDB</small> until
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either another <code>read(0, …)</code> is requested by the target, or debugging
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is stopped at the user’s request.
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