fork/exec & close file descriptors

[random832 at fastmail.us]

On Wed, Jun 3, 2015, at 09:32, Chris Angelico wrote:
> Write an editor that opens a file and holds it open until the user's
> done with it. Have something that lets you shell out for whatever
> reason. Then trigger the shell-out, and instantly SIGSTOP the child
> process, before it does its work - or just have a really heavily
> loaded system, so it can't get a time slice. Now close the file in the
> UI, which results in the file being closed in the parent. Right, now
> let the child run... and there it goes, closing the file.

The parent should be waiting for the child process. If it shouldn't wait
for the command, then the child process should spawn a grandchild
process, after closing the file descriptors. This is how the text editor
I use actually works (more or less. In fact, the way to run a process it
won't wait for is to run it as a background shell command. If you STOP
the shell itself, the editor will be stuck waiting.)