getlogin() not working on Windows Subsystem for Linux (WSL)

Question

It seems, that the getlogin() function is not working when called from the Linux subsystem on Windows (it always returns null).

This leads to two questions:

Is there a working alternative?
Is it possible to determine if we are on a "normal" Linux or a "Windows Linux" like stated here?

It's not a system call. It relies on a login, specifically a utmp record, I guess your WSL is not bothering to set that up when you open a WSL window. getlogin is probably working correctly, it's just telling you there is no utmp record :-P. If you want some alternative, you need to explain exactly what behaviour you want. — sourcejedi, Commented May 11, 2019 at 14:27
@sourcejedi You're right. Somewhere else, I read that this utmp record doesn't exist (which seems to produce some more problems). I just need an easy way to display the username of the user who started the process. — TimSch, Commented May 11, 2019 at 14:40
good start. Is it a set-uid process, or does it run with the same UID as the process that exec()'d it ? Do you want sudo my-program to show root ? — sourcejedi, Commented May 11, 2019 at 14:55

sourcejedi · Accepted Answer · 2019-05-11 14:56:12Z

1

Assuming you are still running as the same user: getuid() then resolve it to a user name.

answered May 11, 2019 at 14:56

sourcejedi

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