Re^2: How to close all open file descriptors after a fork?

[nneul]

The problem is the "unknown context". This is in a subroutine that needs to spawn a background task, called from code that is not under my control. Therefore, I don't know what FDs/FHs are open.

[blazar]

Well, in that case you may want to choose a way, to "spawn a background task" that will give you the pid of that task, and hopefully if you're under an OS that will let you access the relevant info for that process, you could check that.

For example under Linux you will be able, and may want to examine "/proc/$pid/fd/".