Emacs Org-mode + Letter class = Unknown latex class 'letter'

Question

I want to use Emacs with org-mode to export notes using 'letter' class. Texlive is installed in a Mac, and have many classes to export. But Emacs in org-mode only work with: article, report and book:

#+LATEX_CLASS: letter

But when I go to export I get the message:

Unknown LaTeX class 'letter'

If use 'article' and open the generated .tex file changing 'article' with 'letter' and exec from terminal 'pdflatex' passing the .tex file as a param then export a PDF correctly using the letter class. How can I use 'letter' class or others that come with Texlive inside of Emacs and Org-mode?

Thank you.

Answer 1

Although the answer by @Robert is perfectly correct, just a more detailed answer: Org is only "aware" of (i.e., can only handle/export) the LaTeX classes defined in the variable org-latex-classes. If you want Org to handle more classes than the default setting, you have to add manually the support for those classes, by customizing the value of this lisp variable. For example, you can add the following lines in your init.el (or .emacs) file:

  (add-to-list 'org-latex-classes
           '("letter"
         "\\documentclass{letter}"
         ("\\section{%s}" . "\\section*{%s}")
         ("\\subsection{%s}" . "\\subsection*{%s}")
         ("\\subsubsection{%s}" . "\\subsubsection*{%s}")))

The first link posted by Robert explains how to better customize (if needed) the support of section headers for this class.

Answer 2

see https://orgmode.org/manual/LaTeX-header-and-sectioning.html#LaTeX-header-and-sectioning You can customize org-latex-classes like https://superuser.com/questions/896741/how-do-i-configure-org-latex-classes-in-emacs HTH