wireguard.exe no MessageBox option?

[Jason A. Donenfeld]

Hi Andrew,

It's a bit tricky, because UI apps are treated differently than
console apps: cmd.exe won't wait for them to complete, and they get
empty stdio handles. But I've used the latter property to detect
what's up and hopefully achieve some kind of compromise. Let me know
if this commit does the trick:

https://git.zx2c4.com/wireguard-windows/commit/?id=ed59b1b2e834b6d35b11bab63551b21bc60d7f35

Basically, if stderr is available, logs go there. Otherwise if stdout
is available, logs go there. Otherwise errors show in a message box.

So this should allow you to do things like:

wireguard /installtunnelservice ... 2>C:\path\to\log.txt

Jason