Re: AIX and Interix also do early PID recycling.

[Michael Haubenwallner]

On 08/28/2012 09:21 AM, Roman Rakus wrote:
> On 08/01/2012 03:13 PM, Chet Ramey wrote:
>> On 7/30/12 10:41 AM, Roman Rakus wrote:
>>
>>> Hmm... I don't know much about boundaries of maximum number of user
>>> processes. But anyway - do you think that (re)changing js.c_childmax (when
>>> `ulimit -u' is changed) is not good?
>> Maybe it's ok up to some fixed upper bound.  But if you're going to have
>> that fixed upper bound, why not just use it as the number of job exit
>> statuses to remember all the time?
>>
> I prepared a patch which add configure option to enable and set the number of 
> job exit statuses to remember.

Why not simply use the static CHILD_MAX value instead?
Feels like this is what the spec means - and conforming kernels do not 
guarantee for more
than that anyway, counting synchronous, asynchronous and substituted commands 
together.

However, Linux has stopped defining CHILD_MAX (not so) recently (value was 999),
so _POSIX_CHILD_MAX (25 is current value, 6 is old value) would feel correct 
then...

Anyway, now I do understand why people use pipes instead to get the child's 
exitstatus:
http://thread.gmane.org/gmane.linux.gentoo.portage.devel/3446/focus=3451

/haubi/