PR_IMPLEMENT(PRStatus) PR_CallOnce( PRCallOnceType *once, PRCallOnceFN    func)
PR_IMPLEMENT(PRInt32) NSS_GetError(void)
PR_IMPLEMENT(PRStatus) PR_CallOnce(    PRCallOnceType *once,    PRCallOnceFN    func){    /* This is not really atomic! */    if (1 == PR_AtomicIncrement(&once->initialized)) {	once->status = (*func)();    }  else {    	/* Should wait to be sure that func has finished before returning. */    }    return once->status;}