Roland McGrath wrote:
But...posix_spawn doesn't give you any way to delete *all* file descriptors
and if you try to collect them before spawning, there is a race in a
multithreaded program.
This is something you should never want to do. There is notoriously no
good way to do it on some systems, where getdtablesize() can return
RLIM_INFINITY and is not proper to use in a loop.
Use FD_CLOEXEC when you open the descriptor in the first place.
We also need to chdir() before calling exec. And while some descriptors
already have FD_CLOEXEC set, it's not easy to guarantee this for all of
them.
- Michael.
