Re: (bash) How (really!) does the "current job" get determined?

On 2024-10-05, Kenny McCormack <gazelle@shell.xmission.com> wrote:

The problem of re-used pids is something people frequently worry about, but
which is (for all practical purposes) never seen in real life.  For one
thing, even in the old days of 15 bit pids, it is still basically
impossible for it to cycle all the way through in any sort of reasonable
time frame.  Nowadays, we have 22 bit pids, so it is even less likely (*).

"We" do?  Offhand, I don't know the size of pid_t, much less how
much of its numerical range is actually used.  There are trivial
concerns, such as how many columns PIDs take up in the output of
ps(1).

    1) As far as I know, all "normal" Unixes use the simple cycle method of
    allocating pids - i.e., just keep going up by 1 until you reach the max,
    then start over again at 1 (or 2).  But I think at one point, it was
    thought that having "predictable" pids was somehow bad for "security",
    so they had a random assignment method.

I thought random assignment of PIDs was standard by now.
Okay, on FreeBSD it isn't but can be enabled.

--
Christian "naddy" Weisgerber                          naddy@mips.inka.de