if (lastuid == uid && buf[0] && buf[0] != ':')
if (lastuid == uid && buf[0] != '\0' && buf[0] != ':')
extern char *getusername(uid, file, opts)	UID_T uid;	char *file;	opt_t opts;{	static char buf[100];	static UID_T lastuid = (UID_T)-1;	struct passwd *pwd = NULL;	/*	 * The value of opts may have changed so we always	 * do the opts check.	 */  	if (IS_ON(opts, DO_NUMCHKOWNER)) { 		(void) sprintf(buf, ":%d", uid);		return(buf);  	}	/*	 * Try to avoid getpwuid() call.	 */	if (lastuid == uid && buf[0] && buf[0] != ':')		return(buf);	lastuid = uid;	if ((pwd = getpwuid(uid)) == NULL) {		message(MT_WARNING,			"%s: No password entry for uid %d", file, uid);		(void) sprintf(buf, ":%d", uid);	} else		(void) strcpy(buf, pwd->pw_name);	return(buf);}