dokas@cs.umn.edu (Paul B Dokas) writes:
>What appears to be happening is this:  if two children die at almost
>the same instant then the first child to die will queue up a SIGCHLD,
>but when the second dies, the kernel notices that a SIGCHLD is already
>pending and then throws out the second SIGCHLD.

That's correct.  Signals aren't queued.  You have to wait3() in a loop
with options WNOHANG|WUNTRACED until no dead childs are collected.

-- 
Christoph Badura
Verlag O'Reilly