About the environmental variables on different systems

Question

I've a problem with this statement:

(setq org-mobile-directory "~/Dropbox/MobileOrg")

It works in Linux (and maybe in OSX too), because the tilde is expanded in /home/<me>/Dropbox/MobileOrg. It doesn't in Windows, because emacs expand the tilde into C:\Users\<me>\AppData\Roaming\ while Dropbox refers to the %USERPROFILE% environmental variable, which is expanded into C:\Users\<me>\.

I already know I can use two different files depending to the OS, or introduce a condition. But I'm wondering if I can somehow avail of some variable I did not take in consideration. Any clue?

Thanks in advance.

Answer 1

You can set %HOME% to c:\Users\<me>\, and Emacs will then consider that your home directory. The downside is that you may have to move your .emacs to that directory too.

More information here: https://www.gnu.org/software/emacs/manual/html_node/emacs/Windows-HOME.html

Answer 2

You could check the system type and then set a variable that holds the location of your Dropbox directory on that platform. For example:

(setq dropbox (if (eq system-type 'windows-nt)
                  (concat (file-name-as-directory (getenv "USERPROFILE"))
                          "Dropbox")
                "~/Dropbox"))

Once you've got that you can easily setup any other variables you need without them needing to know where the Dropbox actually is:

(setq org-mobile-directory (concat (file-name-as-directory dropbox)
                                   "MobileOrg"))

I use something like this to store all sorts of Emacs related stuff such bookmarks, abbreviations, and various bits of code.