Frequently Asked Questions about AUCTeX
***************************************

  1. Something is not working correctly.  What should I do?

     Well, you might have guessed it, the first place to look is in the
     available documentation packaged with AUCTeX.  This could be the
     release notes (in the 'RELEASE' file) or the news section of the
     manual in case you are experiencing problems after an upgrade, the
     'INSTALL' file in case you are having problems with the
     installation, the section about bugs in the manual in case you
     encountered a bug or the relevant sections in the manual for other
     related problems.

     If this did not help, you can send a bug report to the AUCTeX bug
     reporting list by using the command 'M-x TeX-submit-bug-report
     <RET>'.  But before you do this, you can try to get more
     information about the problem at hand which might also help you
     locate the cause of the error yourself.

     First, you can try to generate a so-called backtrace which shows
     the functions involved in a program error.  In order to do this,
     start Emacs with the command line 'emacs --debug-init' and/or put
     the line

          (setq debug-on-error t)

     as the first line into your init file.  After Emacs has started,
     you can load a file which triggers the error and a new window
     should pop up showing the backtrace.  If you get such a backtrace,
     please include it in the bug report.

     Second, you can try to figure out if something in your personal or
     site configuration triggers the error by starting Emacs without
     such customizations.  You can do this by invoking Emacs with the
     command line 'emacs -q -no-site-file -l auctex'.  The '-l' option
     loads 'auctex.el' which you normally do in your init file.  After
     you have started Emacs like this, you can load the file triggering
     the error.  If everything is working now, you know that you have to
     search either in the site configuration file or your personal init
     file for statements related to the problem.

  2. What versions of Emacs are supported?

     AUCTeX was tested with GNU Emacs 24.3.  Older versions may work but
     are unsupported.

  3. What should I do when './configure' does not find programs like
     'latex'?

     This is problem often encountered on Windows.  Make sure that the
     'PATH' environment variable includes the directories containing the
     relevant programs, as described in the file 'INSTALL.windows'

  4. Why doesn't the completion, style file, or multifile stuff work?

     It must be enabled first, insert this in your init file:

          (setq-default TeX-master nil)
          (setq TeX-parse-self t)
          (setq TeX-auto-save t)

     Read also the chapters about parsing and multifile documents in the
     manual.

  5. Why doesn't 'TeX-save-document' work?

     'TeX-check-path' has to contain "'./'" somewhere.

  6. Why is the information in 'foo.tex' forgotten when I save
     'foo.bib'?

     For various reasons, AUCTeX ignores the extension when it stores
     information about a file, so you should use unique base names for
     your files.  E.g. rename 'foo.bib' to 'foob.bib'.

  7. Why doesn't AUCTeX signal when processing a document is done?

     If the message in the minibuffer stays "Type 'C-c C-l' to display
     results of compilation.", you probably have a misconfiguration in
     your init file ('.emacs', 'init.el' or similar).  To track this
     down either search in the '*Messages*' buffer for an error message
     or put '(setq debug-on-error t)' as the first line into your init
     file, restart Emacs and open a LaTeX file.  Emacs will complain
     loudly by opening a debugging buffer as soon as an error occurs.
     The information in the debugging buffer can help you find the cause
     of the error in your init file.

  8. Why does 'TeX-next-error' ('C-c `') fail?

     If 'TeX-file-line-error' is set to nil (not the default), these
     sort of failures might be related to the the fact that when writing
     the log file, TeX puts information related to a file, including
     error messages, between a pair of parentheses.  In this scenario
     AUCTeX determines the file where the error happened by parsing the
     log file and counting the parentheses.  This can fail when there
     are other, unbalanced parentheses present.

     Activating so-called 'file:line:error' messages for the log file
     usually solves this issue, as these kind of messages are are easier
     to parse; however, they may lack some details.  Activation can be
     done either in the configuration of your TeX system (consult its
     manual to see where this is) or by simply keeping the variable
     'TeX-file-line-error' to the default value of non-nil.

  9. What does AUC stand for?

     AUCTeX came into being at Aalborg University in Denmark.  Back then
     the Danish name of the university was Aalborg Universitetscenter;
     AUC for short.

Frequently Asked Questions about preview-latex
**********************************************

Frequently Asked Questions about preview-latex
1 Introduction
  1.1 How can I contribute to the FAQ?
2 Requirements
  2.1 Which version of Emacs is needed?
  2.2 Which versions of Ghostscript and AUCTeX are needed?
  2.3 I have trouble with the display format...
  2.4 For which OS does preview work?
3 Installation Trouble
  3.1 I just get 'LaTeX found no preview images'.
4 Customization
  4.1 How to include additional environments like 'enumerate'
  4.2 What if I don't want to change the document?
  4.3 Suddenly I get gazillions of ridiculous pages?!?
  4.4 Does preview-latex work with presentation classes?
5 Troubleshooting
  5.1 Preview causes all sort of strange error messages
  5.2 Why do my DVI and PDF output files vanish?
  5.3 My output file suddenly only contains preview images?!
6 preview-latex when not using LaTeX
  6.1 Does preview-latex work with PDFLaTeX?
  6.2 Does preview-latex work with 'elatex'?
  6.3 Does preview-latex work with ConTeXt?
  6.4 Does preview-latex work with plain TeX?
1 Introduction
**************

1.1 How can I contribute to the FAQ?
====================================

Send an email with the subject:
     Preview FAQ
   to <auctex-devel@gnu.org>.

2 Requirements
**************

2.1 Which version of Emacs is needed?
=====================================

preview-latex nominally requires GNU Emacs with a version of at least
24.3.

2.2 Which versions of Ghostscript and AUCTeX are needed?
========================================================

We recommend to use GNU or AFPL Ghostscript with a version of at least
7.07.

   preview-latex has been distributed as part of AUCTeX since version
11.80.  If your version of AUCTeX is older than that, or if it does not
contain a working copy of preview-latex, complain to wherever you got it
from.

2.3 I have trouble with the display format...
=============================================

We recommend keeping the variable 'preview-image-type' set to 'dvipng'
(if you have it installed) or 'png'.  This is the default and can be set
via the 'Preview/Customize' menu.

   All other formats are known to have inconveniences, either in file
size or quality.  There are some Emacs versions around not supporting
PNG; the proper way to deal with that is to complain to your Emacs
provider.  Short of that, checking out PNM or JPEG formats might be a
good way to find out whether the lack of PNG format support might be the
only problem with your Emacs.

2.4 For which OS does preview work?
===================================

It is known to work under the X Window System for Linux and for several
flavors of Unix: we have reports for HP and Solaris.

   There are several development versions of Emacs around for native
MacOS Carbon, and preview-latex is working with them, too.

   With Windows, both native Emacs and Cygwin Emacs should work.
However, it is known that MiKTeX (https://miktex.org/) sometimes doesn't
work with preview-latex.  In that case, use TeX Live
(https://tug.org/texlive/) instead.

3 Installation Trouble
**********************

3.1 I just get 'LaTeX found no preview images'.
===============================================

The reason for this is that LaTeX found no preview images in the
document in question.

   One reason might be that there are no previews to be seen.  If you
have not used preview-latex before, you might not know its manner of
operation.  One sure-fire way to test if you just have a document where
no previews are to be found is to use the provided example document
'circ.tex' (you will have to copy it to some directory where you have
write permissions).  If the symptom persists, you have a problem, and
the problem is most likely a LaTeX problem.  Here are possible reasons:

Filename database not updated
     Various TeX distributions have their own ways of knowing where the
     files are without actually searching directories.  The normal
     preview-latex installation should detect common tools for that
     purpose and use them.  If this goes wrong, or if the files get
     installed into a place where they are not looked for, the LaTeX run
     will fail.

An incomplete manual installation
     This should not happen if you followed installation instructions.
     Unfortunately, people know better all the time.  If only
     'preview.sty' gets installed without a set of supplementary files
     also in the 'latex' subdirectory, preview-latex runs will not
     generate any errors, but they will not produce any previews,
     either.

An outdated 'preview' installation
     The 'preview.sty' package is useful for more than just
     preview-latex.  For example, it is part of TeX Live.  So you have
     to make sure that preview-latex does not get to work with outdated
     style and configuration files: some newer features will not work
     with older TeX style files, and really old files will make
     preview-latex fail completely.  There usual is a local 'texmf'
     tree, or even a user-specific tree that are searched before the
     default tree.  Make sure that the first version of those files that
     gets found is the correct one.

4 Customization
***************

4.1 How to include additional environments like 'enumerate'
===========================================================

By default, preview-latex is intended mainly for displaying mathematical
formulas, so environments like 'enumerate' or 'tabular' (except where
contained in a float) are not included.  You can include them however
manually by adding the lines:

     \usepackage[displaymath,textmath,sections,graphics,floats]{preview}
     \PreviewEnvironment{enumerate}
in your document header, that is before

     \begin{document}
In general, 'preview' should be loaded as the last thing before the
start of document.

   Be aware that

     \PreviewEnvironment{...}
does not accept a comma separated list!  Also note that by putting more
and more

     \PreviewEnvironment{...}
in your document, it will look more and more like a DVI file preview
when running preview-latex.  Since each preview is treated as one large
monolithic block by Emacs, one should really restrict previews to those
elements where the improvement in visual representation more than makes
up for the decreased editability.

4.2 What if I don't want to change the document?
================================================

The easiest way is to generate a configuration file in the current
directory.  You can basically either create 'prdefault.cfg' which is
used for any use of the 'preview' package, or you can use 'prauctex.cfg'
which only applies to the use from with Emacs.  Let us assume you use
the latter.  In that case you should write something like

     \InputIfFileExists{preview/prauctex.cfg}{}{}
     \PreviewEnvironment{enumerate}
in it.  The first line inputs the system-wide default configuration (the
file name should match that, but not your own 'prauctex.cfg'), then you
add your own stuff.

4.3 Suddenly I get gazillions of ridiculous pages?!?
====================================================

When preview-latex works on extracting its stuff, it typesets each
single preview on a page of its own.  This only happens when actual
previews get generated.  Now if you want to configure preview-latex in
your document, you need to add your own '\usepackage' call to 'preview'
so that it will be able to interpret its various definition commands.
It is an error to add the 'active' option to this invocation: you don't
want the package to be active unless preview-latex itself enables the
previewing operation (which it will).

4.4 Does preview-latex work with presentation classes?
======================================================

preview-latex should work with most presentation classes.  However,
since those classes often have macros or pseudo environments
encompassing a complete slide, you will need to use the customization
facilities of 'preview.sty' to tell it how to resolve this, whether you
want no previews, previews of whole slides or previews of inner
material.

5 Troubleshooting
*****************

5.1 Preview causes all sort of strange error messages
=====================================================

When running preview-latex and taking a look at either log file or
terminal output, lots of messages like

     ! Preview: Snippet 3 started.
     <-><->

     l.52 \item Sie lassen sich als Funktion $
                                              y = f(x)$ darstellen.
     ! Preview: Snippet 3 ended.(491520+163840x2494310).
     <-><->

     l.52 \item Sie lassen sich als Funktion $y = f(x)$
                                                        darstellen.
appear (previous versions generated messages looking even more like
errors).  Those are not real errors (as will be noted in the log file).
Or rather, while they *are* really TeX error messages, they are
intentional.  This currently is the only reliable way to pass the
information from the LaTeX run of preview-latex to its Emacs part about
where the previews originated in the source text.  Since they are actual
errors, you will also get AUCTeX to state
     Preview-LaTeX exited as expected with code 1 at Wed Sep  4 17:03:30
after the LaTeX run in the run buffer.  This merely indicates that
errors were present, and errors will always be present when
preview-latex is operating.  There might be also real errors, so in case
of doubt, look for them explicitly in either run buffer or the resulting
'.log' file.

5.2 Why do my DVI and PDF output files vanish?
==============================================

In order to produce the preview images preview-latex runs LaTeX on the
master or region file.  The resulting DVI or PDF file can happen to have
the same name as the output file of a regular LaTeX run.  So the regular
output file gets overwritten and is subsequently deleted by
preview-latex.

5.3 My output file suddenly only contains preview images?!
==========================================================

As mentioned in the previews FAQ entry, preview-latex might use the file
name of the original output file for the creation of preview images.  If
the original output file is being displayed with a viewer when this
happens, you might see strange effects depending on the viewer, e.g. a
message about the file being corrupted or the display of all the preview
images instead of your typeset document.  (Also *note Customization::.)

6 preview-latex when not using LaTeX
************************************

6.1 Does preview-latex work with PDFLaTeX?
==========================================

Yes, as long as you use AUCTeX's own PDFLaTeX mode and have not messed
with 'TeX-command-list'.

6.2 Does preview-latex work with 'elatex'?
==========================================

No problem here.  If you configure your AUCTeX to use 'elatex', or
simply have 'latex' point to 'elatex', this will work fine.  Modern TeX
distributions use eTeX for LaTeX, anyway.

6.3 Does preview-latex work with ConTeXt?
=========================================

In short, no.  The 'preview' package is LaTeX-dependent.  Adding support
for other formats requires volunteers.

6.4 Does preview-latex work with plain TeX?
===========================================

Again, no.  Restructuring the 'preview' package for 'plain' operation
would be required.  Volunteers welcome.

   In some cases you might get around by making a wrapper pseudo-Master
file looking like the following:

     \documentclass{article}
     \usepackage{plain}
     \begin{document}
     \begin{plain}
     \input myplainfile
     \end{plain}
     \end{document}
