fork error using kevent rather than wait(2)

[Luke Small]

I made a simple case. I need to have a kevent wait for both incoming socket
communications and for the forked process to finish its run evaluating
shared data.
I show that it fails to merely wait for NOTE_EXIT calls and I'd guess
making the kernel aware that the process died.

limit_test.c shows that there is a fork error when it runs a while even if
it waits for the forked process to die, where it doesn't occur by simply
using wait(2), which is in comments below it.

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/event.h>
#include <sys/socket.h>
#include <sys/wait.h>

int main()
{
    int i;
    int k;
    int kq;
    int integer;
    struct kevent ke;
    
    kq = kqueue();
    if (kq == -1)
	    err(1, "kq!");
	    
    for (i = 0; i < 2000; ++i)
    {

	integer = fork();
	switch(integer)
	{
		case -1:
			err(1, "fork!");
		case 0:
			_exit(0);
		default:
			break;
	}

	EV_SET(&ke, integer, EVFILT_PROC, EV_ADD | EV_ONESHOT, NOTE_EXIT, 0, NULL);
	if (kevent(kq, &ke, 1, NULL, 0, NULL) == -1)
		err(1, "kevent");
	
	
	k = kevent(kq, NULL, 0, &ke, 1, NULL);
	if (k == -1)
		err(1, "k == -1");
	if(ke.flags & EV_ERROR)
		err(1, "EV_ERROR");

	printf("%d\n", i);
    }
}

/*
int main()
{
    int i;
    int integer;
    for (i = 0; i < 2000; ++i)
    {
	integer = fork();
	switch(integer)
	{
		case -1:
			err(1, "fork!");
		case 0:
			_exit(0);
		default:
			break;
	}
	wait(NULL);
	printf("%d\n", i);
    }
}
*/