<html lang="en"> <head> <title>Debugger Banner - SBCL 1.0.31 User Manual</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="SBCL 1.0.31 User Manual"> <meta name="generator" content="makeinfo 4.13"> <link title="Top" rel="start" href="index.html#Top"> <link rel="up" href="Debugger-Entry.html#Debugger-Entry" title="Debugger Entry"> <link rel="next" href="Debugger-Invocation.html#Debugger-Invocation" title="Debugger Invocation"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <!-- This manual is part of the SBCL software system. See the `README' file for more information. This manual is largely derived from the manual for the CMUCL system, which was produced at Carnegie Mellon University and later released into the public domain. This manual is in the public domain and is provided with absolutely no warranty. See the `COPYING' and `CREDITS' files for more information. --> <meta http-equiv="Content-Style-Type" content="text/css"> <style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller } span.sc { font-variant:small-caps } span.roman { font-family:serif; font-weight:normal; } span.sansserif { font-family:sans-serif; font-weight:normal; } --></style> </head> <body> <div class="node"> <a name="Debugger-Banner"></a> <p> Next: <a rel="next" accesskey="n" href="Debugger-Invocation.html#Debugger-Invocation">Debugger Invocation</a>, Up: <a rel="up" accesskey="u" href="Debugger-Entry.html#Debugger-Entry">Debugger Entry</a> <hr> </div> <!-- node-name, next, previous, up --> <h4 class="subsection">5.1.1 Debugger Banner</h4> <p>When you enter the debugger, it looks something like this: <pre class="example"> debugger invoked on a TYPE-ERROR in thread 11184: The value 3 is not of type LIST. You can type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL. restarts (invokable by number or by possibly-abbreviated name): 0: [ABORT ] Reduce debugger level (leaving debugger, returning to toplevel). 1: [TOPLEVEL] Restart at toplevel READ/EVAL/PRINT loop. (CAR 1 3) 0] </pre> <p>The first group of lines describe what the error was that put us in the debugger. In this case <code>car</code> was called on <code>3</code>, causing a <code>type-error</code>. <p>This is followed by the “beginner help line”, which appears only if <code>sb-ext:*debugger-beginner-help*</code> is true (default). <p>Next comes a listing of the active restart names, along with their descriptions – the ways we can restart execution after this error. In this case, both options return to top-level. Restarts can be selected by entering the corresponding number or name. <p>The current frame appears right underneath the restarts, immediately followed by the debugger prompt. </body></html>