#include	"u.h"#include	"lib.h"#include	"dat.h"#include	"fns.h"#include	"error.h" longsysexits(ulong *arg){	char *status;	char *inval = "invalid exit string";	char buf[ERRMAX]; 	status = (char*)arg[0];	if(status){		if(waserror())			status = inval;		else{			validaddr((ulong)status, 1, 0);			if(vmemchr(status, 0, ERRMAX) == 0){				memmove(buf, status, ERRMAX);				buf[ERRMAX-1] = 0;				status = buf;			}		}		poperror(); 	}	pexit(status, 1);	return 0;		/* not reached */}