;; Function obtained from https://wiki.archlinux.org/index.php/Emacs#SyncTeX_support

(defcustom tex-my-viewer "zathura --fork -s -x \"emacsclient --eval '(progn (switch-to-buffer  (file-name-nondirectory \"'\"'\"%{input}\"'\"'\")) (goto-line %{line}))'\"" 
  "PDF Viewer for TeX documents. You may want to fork the viewer
so that it detects when the same document is launched twice, and
persists when Emacs gets closed.

Simple command:

  zathura --fork

We can use

  emacsclient --eval '(progn (switch-to-buffer  (file-name-nondirectory \"%{input}\")) (goto-line %{line}))'

to reverse-search a pdf using SyncTeX. Note that the quotes and double-quotes matter and must be escaped appropriately."
:safe 'stringp)