Chapters:
1: Introduction
2: Simple example
3: Invocation
4: Finer Control
5: X-Y Plots
6: Contour Plots
7: Image Plots
8: Examples
9: Gri Commands
10: Programming
11: Environment
12: Emacs Mode
13: History
14: Installation
15: Gri Bugs
16: Test Suite
17: Gri in Press
18: Acknowledgments
19: License
Indices:
Concepts
Commands
Variables

## 10.14: Error Messages

Gri error messages are in three types:

1. Operating system error messages, such as ``segmentation fault`'. These should never appear, and indicate a bug in Gri. Please report these to the author (see Reporting Bugs).
2. Internal Gri error messages. The message starts with the words ``FATAL error`', and quotes a file number and a line number, e.g.

       FATAL error: startup.c:199: ...

   Such errors indicate either a deficiency in your computer (e.g. insufficient storage space) or an internal bug in Gri. If the message does not indicate running out of storage, please report the error to the author (see Reporting Bugs).

   For fatal error messages on a unix system, Gri dumps core, unless you have turned that feature off, with the ``ulimit -c 0`' unix command in a startup file. This creates a file called ``core`', which can help you in diagnosing the Gri bug. If you have the ``gdb`' debugger, just type ``gdb gri core`' and then type ``where`' to get a traceback stack. Please email this with your other information about the Gri bug.

3. An indication that your commandfile is flawed, either in syntax or in meaning. These messages end with a line indicating the offending line in your commandfile, e.g. the command ``set x axis 0 1 -1`' yields:

       ERROR: `set x axis .left. .right. .incBig.'
               has .incBig. of wrong sign
        Bad command:  `set x axis 0 1 -1 '

   Normally, such error messages do not indicate a flaw in Gri, but rather in your reasoning, so report them to the author only if you are very sure that a Gri bug must underly them.