Re: wait() spec (SIGCHLD ignored)

[Roland McGrath <roland@xxxxxxxxxx>]

I think you are reading it wrong.  In the scenario you described, your
previously-terminated child was not transformed into a zombie process.  

In _exit() and the "Signal Concepts" section, the standard specifies when a
process "shall be transformed into a zombie process."  It's when its parent
didn't use SIG_IGN or SA_NOCLDWAIT for SIGCHLD.

The wait() wording means that e.g. if you had SIGCHLD set to SIG_DFL, then
had some children die, then subsequently changed SIGCHLD to SIG_IGN and
then called wait(), you would get those previously-dead children.  However,
if SIGCHLD was set to SIG_IGN before any children died, then the clause
applies normally--wait() blocks until all are dead, then returns ECHILD.


Thanks,
Roland