<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Copyright (C) 1988-2020 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being "Free Software" and "Free Software Needs Free Documentation", with the Front-Cover Texts being "A GNU Manual," and with the Back-Cover Texts as in (a) below. (a) The FSF's Back-Cover Text is: "You are free to copy and modify this GNU Manual. Buying copies from GNU Press supports the FSF in developing GNU and promoting software freedom." --> <!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ --> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>The F Reply Packet (Debugging with GDB)</title> <meta name="description" content="The F Reply Packet (Debugging with GDB)"> <meta name="keywords" content="The F Reply Packet (Debugging with GDB)"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="makeinfo"> <link href="index.html#Top" rel="start" title="Top"> <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> <link href="File_002dI_002fO-Remote-Protocol-Extension.html#File_002dI_002fO-Remote-Protocol-Extension" rel="up" title="File-I/O Remote Protocol Extension"> <link href="The-Ctrl_002dC-Message.html#The-Ctrl_002dC-Message" rel="next" title="The Ctrl-C Message"> <link href="The-F-Request-Packet.html#The-F-Request-Packet" rel="prev" title="The F Request Packet"> <style type="text/css"> <!-- a.summary-letter {text-decoration: none} blockquote.indentedblock {margin-right: 0em} blockquote.smallindentedblock {margin-right: 0em; font-size: smaller} blockquote.smallquotation {font-size: smaller} div.display {margin-left: 3.2em} div.example {margin-left: 3.2em} div.lisp {margin-left: 3.2em} div.smalldisplay {margin-left: 3.2em} div.smallexample {margin-left: 3.2em} div.smalllisp {margin-left: 3.2em} kbd {font-style: oblique} pre.display {font-family: inherit} pre.format {font-family: inherit} pre.menu-comment {font-family: serif} pre.menu-preformatted {font-family: serif} pre.smalldisplay {font-family: inherit; font-size: smaller} pre.smallexample {font-size: smaller} pre.smallformat {font-family: inherit; font-size: smaller} pre.smalllisp {font-size: smaller} span.nolinebreak {white-space: nowrap} span.roman {font-family: initial; font-weight: normal} span.sansserif {font-family: sans-serif; font-weight: normal} ul.no-bullet {list-style: none} --> </style> </head> <body lang="en"> <a name="The-F-Reply-Packet"></a> <div class="header"> <p> Next: <a href="The-Ctrl_002dC-Message.html#The-Ctrl_002dC-Message" accesskey="n" rel="next">The Ctrl-C Message</a>, Previous: <a href="The-F-Request-Packet.html#The-F-Request-Packet" accesskey="p" rel="prev">The F Request Packet</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> </div> <hr> <a name="The-F-Reply-Packet-1"></a> <h4 class="subsection">E.13.4 The <code>F</code> Reply Packet</h4> <a name="index-file_002di_002fo-reply-packet"></a> <a name="index-F-reply-packet"></a> <p>The <code>F</code> reply packet has the following format: </p> <dl compact="compact"> <dt>‘<samp>F<var>retcode</var>,<var>errno</var>,<var>Ctrl-C flag</var>;<var>call-specific attachment</var></samp>’</dt> <dd> <p><var>retcode</var> is the return code of the system call as hexadecimal value. </p> <p><var>errno</var> is the <code>errno</code> set by the call, in protocol-specific representation. This parameter can be omitted if the call was successful. </p> <p><var>Ctrl-C flag</var> is only sent if the user requested a break. In this case, <var>errno</var> must be sent as well, even if the call was successful. The <var>Ctrl-C flag</var> itself consists of the character ‘<samp>C</samp>’: </p> <div class="smallexample"> <pre class="smallexample">F0,0,C </pre></div> <p>or, if the call was interrupted before the host call has been performed: </p> <div class="smallexample"> <pre class="smallexample">F-1,4,C </pre></div> <p>assuming 4 is the protocol-specific representation of <code>EINTR</code>. </p> </dd> </dl> </body> </html>