Using org in emacs batch mode

Question

I'd like to export an org file to LaTeX from the command line. I have created a file export.el with the following contents (simplified to reproduce the problem):

(require 'org)

(when (not (assoc "scrreprt" org-latex-classes))
  (push '("scrreprt"
          (assoc "report" org-latex-classes))
        org-latex-classes))

 (with-current-buffer (find-file-noselect "contents.org")
   (org-latex-export-to-latex nil nil nil t)))

And then I tried to run it from the shell:

$ emacs -Q --batch -l export.el 
Symbol's value as variable is void: org-latex-classes

It seems that I am missing some org functionality. How do I find out what else I have to require in order to get org-latex-classes defined?

(Omitting the -Q option does not help either, but even if it helped my question about finding the right require would stand).

Answer 1

I presume you have access to org-latex-classes when you start up Emacs for interactive use, so something in your init file is loading it. You can check which library defines org-latex-classes with C-h v org-latex-classes (or describe-variable). It tells you that

org-latex-classes is a variable defined in ox-latex.el.

As such, you also need to (require 'ox-latex) for Emacs to recognize that variable. It should also work to (require 'ox) instead.

Also see this SuperUser post on the question.