---
layout: default
title: Bugs
menu: true
---

<ul class="button-group">
  <li><a href="http://savannah.gnu.org/bugs/?func=additem&group=octave" class="button">Report</a></li>
  <li><a href="http://savannah.gnu.org/bugs/?func=search&group=octave" class="button">Search</a></li>
  <li><a href="http://savannah.gnu.org/bugs/?group=octave" class="button">Browse</a></li>
</ul>

Your bug reports play an essential role in making Octave reliable.
You can make fixing problems easier by following the guidelines below.


## Where and How to Send Bug Reports

To report a bug in Octave,
<a href="http://savannah.gnu.org/bugs/?func=additem&group=octave">submit
a bug report</a> using the bug tracker.

Please do <strong>not</strong> send bug reports to the
<samp>help-octave</samp> mailing list.  Most users of Octave do not
want to receive bug reports.

When you encounter a problem, the first thing to do is to see if it
is already known. The best place to look for reported problems is
<a href="http://savannah.gnu.org/bugs/?group=octave">the Octave bug tracker</a>.

The <a href="doc/interpreter/Trouble.html#Trouble">Octave
reference manual</a> also contains a list of known causes of
trouble.

If you your problem does not appear to be known, then you should
report the problem.

Reporting a bug may help you by bringing a solution to your problem,
or it may not.  In any case, the principal function of a bug report is
to help the entire community by making the next version of Octave work
better, so you can contribute to the maintenance of Octave.


## Have You Found a Bug?

If you are not sure whether you have found a bug, here are some guidelines:

  <ul>
    <li>
      If Octave gets a fatal signal, for any input whatever, that is a bug.
      Reliable interpreters never crash.
    </li>

    <li>
      If Octave produces incorrect results, for any input whatever,
      that is a bug.
    </li>

    <li>
      Some output may appear to be incorrect when it is in fact due to a
      program whose behavior is undefined, which happened by chance to give
      the desired results on another system.  For example,
      trigonometric functions may produce different results because of
      differences in the math library or the way floating point
      arithmetic is handled on various systems.
    </li>

    <li>
      If Octave produces an error message for valid input, that is a
      bug.
    </li>

    <li>
      If Octave does not produce an error message for invalid input, that is
      a bug.  However, you should note that your idea of "invalid input"
      might be my idea of "an extension" or "support for traditional
      practice".
    </li>

    <li>
      If you are an experienced user of programs like Octave, your
      suggestions for improvement are welcome in any case.
    </li>
  </ul>


## Making Your Bug Report Count

In order for a bug report to serve its purpose, you must include the
information that makes it possible to fix the bug.

The fundamental principle of reporting bugs usefully is this:
<strong>report all the facts</strong>.  If you are not sure whether to
state a fact or leave it out, state it.

Often people omit facts because they think they know what causes the
problem and they conclude that some details don't matter.  Thus, you
might assume that the name of the variable you use in an example does
not matter.  Well, probably it doesn't, but one cannot be sure.
Perhaps the bug is a stray memory reference which happens to fetch
from the location where that name is stored in memory; perhaps, if the
name were different, the contents of that location would fool the
interpreter into doing the right thing despite the bug.  Play it safe
and give a specific, complete example.

Keep in mind that the purpose of a bug report is to enable someone to
fix the bug if it is not known. Always write your bug reports on
the assumption that the bug is not known.

Sometimes people give a few sketchy facts and ask, "Does this ring a
bell?"  This cannot help us fix a bug.  It is better to send a complete
bug report to begin with.

Try to make your bug report self-contained.  If we have to ask you for
more information, it is best if you include all the previous information
in your response, as well as the information that was missing.

The bug tracker will prompt you for some basic information like
the version of Octave and the operating system you are using.  You
also need to include the following to enable someone to
investigate the bug:

  <ul>
    <li>
      A complete input file that will reproduce the bug.

      A single statement may not be enough of an example--the bug might
      depend on other details that are missing from the single statement where
      the error finally occurs.
    </li>

    <li>
      The command arguments you gave Octave to execute that example
      and observe the bug.  To guarantee you won't omit something important,
      list all the options.

      If we were to try to guess the arguments, we would probably guess wrong
      and then we would not encounter the bug.
    </li>

    <li>
      A description of what behavior you observe that you believe is
      incorrect.  For example, "The interpreter gets a fatal signal," or, "The
      output produced at line 208 is incorrect."
    </li>

    <li>
      The output you expected to see.  Although it might seem obvious
      to you, someone examining the problem might not know what result
      you consider correct.
    </li>

    <li>
      If you wish to suggest changes to the Octave source, send them
      as context diffs.  If you discuss something in the Octave
      source, refer to it by context, not by line number, because the
      line numbers in the development sources probably won't match
      those in your sources.
    </li>
  </ul>


## Sending Patches for Octave

If you have a suggested fix for a bug, please attach it to your
report in the tracker.  Your patch is more likely to be reviewed
if you follow the guidelines  in the Octave manual about to
<a href="doc/interpreter/Basics-of-Generating-a-Changeset.html#Basics-of-Generating-a-Changeset">generate a changeset</a>
and submit patches for Octave.