| <html lang="en"> |
| <head> |
| <title>Exception Handling - Debugging with GDB</title> |
| <meta http-equiv="Content-Type" content="text/html"> |
| <meta name="description" content="Debugging with GDB"> |
| <meta name="generator" content="makeinfo 4.13"> |
| <link title="Top" rel="start" href="index.html#Top"> |
| <link rel="up" href="Python-API.html#Python-API" title="Python API"> |
| <link rel="prev" href="Basic-Python.html#Basic-Python" title="Basic Python"> |
| <link rel="next" href="Values-From-Inferior.html#Values-From-Inferior" title="Values From Inferior"> |
| <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> |
| <!-- |
| Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, |
| 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
| 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.''--> |
| <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> |
| <link rel="stylesheet" type="text/css" href="../cs.css"> |
| </head> |
| <body> |
| <div class="node"> |
| <a name="Exception-Handling"></a> |
| <p> |
| Next: <a rel="next" accesskey="n" href="Values-From-Inferior.html#Values-From-Inferior">Values From Inferior</a>, |
| Previous: <a rel="previous" accesskey="p" href="Basic-Python.html#Basic-Python">Basic Python</a>, |
| Up: <a rel="up" accesskey="u" href="Python-API.html#Python-API">Python API</a> |
| <hr> |
| </div> |
| |
| <h5 class="subsubsection">23.2.2.2 Exception Handling</h5> |
| |
| <p><a name="index-python-exceptions-1606"></a><a name="index-exceptions_002c-python-1607"></a> |
| When executing the <code>python</code> command, Python exceptions |
| uncaught within the Python code are translated to calls to |
| <span class="sc">gdb</span> error-reporting mechanism. If the command that called |
| <code>python</code> does not handle the error, <span class="sc">gdb</span> will |
| terminate it and print an error message containing the Python |
| exception name, the associated value, and the Python call stack |
| backtrace at the point where the exception was raised. Example: |
| |
| <pre class="smallexample"> (gdb) python print foo |
| Traceback (most recent call last): |
| File "<string>", line 1, in <module> |
| NameError: name 'foo' is not defined |
| </pre> |
| <p><span class="sc">gdb</span> errors that happen in <span class="sc">gdb</span> commands invoked by Python |
| code are converted to Python <code>RuntimeError</code> exceptions. User |
| interrupt (via <kbd>C-c</kbd> or by typing <kbd>q</kbd> at a pagination |
| prompt) is translated to a Python <code>KeyboardInterrupt</code> |
| exception. If you catch these exceptions in your Python code, your |
| exception handler will see <code>RuntimeError</code> or |
| <code>KeyboardInterrupt</code> as the exception type, the <span class="sc">gdb</span> error |
| message as its value, and the Python call stack backtrace at the |
| Python statement closest to where the <span class="sc">gdb</span> error occured as the |
| traceback. |
| |
| <p><a name="index-gdb_002eGdbError-1608"></a>When implementing <span class="sc">gdb</span> commands in Python via <code>gdb.Command</code>, |
| it is useful to be able to throw an exception that doesn't cause a |
| traceback to be printed. For example, the user may have invoked the |
| command incorrectly. Use the <code>gdb.GdbError</code> exception |
| to handle this case. Example: |
| |
| <pre class="smallexample"> (gdb) python |
| >class HelloWorld (gdb.Command): |
| > """Greet the whole world.""" |
| > def __init__ (self): |
| > super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_OBSCURE) |
| > def invoke (self, args, from_tty): |
| > argv = gdb.string_to_argv (args) |
| > if len (argv) != 0: |
| > raise gdb.GdbError ("hello-world takes no arguments") |
| > print "Hello, World!" |
| >HelloWorld () |
| >end |
| (gdb) hello-world 42 |
| hello-world takes no arguments |
| </pre> |
| </body></html> |
| |
