Why doesn't Inno Setup constant {userdesktop} work in OutputDir directive and how to fix it?

Question

I created Inno Setup script, which works perfectly, but I wanted to change OutputDir to create the output file on my desktop. But instead of creating output file on desktop it was creating subfolder {userdesktop} at the same directory, where script is and output was inside.

I found solution so far, but I believe there should be better way. What am I missing?

; these attempts didn't work
[Setup]
OutputDir={userdesktop}
; some more attampts:
OutputDir=userdesktop
OutputDir=userdesktop:
OutputDir="{userdesktop}"

; this workaround worked for me
[Setup]
OutputDir=userdocs:..\Desktop

Answer 1

Constants like {userdesktop} are resolved on install time (on the target user's machine), not on compile time (on your development machine). So it makes no sense to use constants in compile-time only directive like OutputDir. And actually it's not possible to use them at all (as it's useless).

---

With the default user profile directory layout, use you can use the userdocs: prefix, as you did:

[Setup]
OutputDir=userdocs:..\Desktop

Though it's not a perfect solution, as the "Documents" folder can be moved by the user and then the userdocs:..\Desktop will not point to the desktop.

---

A more reliable solution is to use USERPROFILE environment variable using GetEnv preprocessor function:

[Setup]
OutputDir={#GetEnv('USERPROFILE')}\Desktop