extending wait4(2) or waitid(2) linux syscall

[Paul Eggert]

On 11/16/18 7:17 AM, Arnd Bergmann wrote:
> we'd want something like
>
> int wait9(...)

We're getting uncomfortably close to the Perlis limit.

"If you have a procedure with 10 parameters, you probably missed some."

Perlis AJ. Epigrams on programming. SIGPLAN Notices. 1982:17(9):7-13. 
https://dx.doi.org/10.1145/947955.1083808 
http://pu.inf.uni-tuebingen.de/users/klaeren/epigrams.html