if (lastgid == gid && buf[0] && buf[0] != ':')
if (lastgid == gid && buf[0] != '\0' && buf[0] != ':')
extern char *getgroupname(gid, file, opts)	GID_T gid;	char *file;	opt_t opts;{	static char buf[100];	static GID_T lastgid = (GID_T)-1;	struct group *grp = NULL;	/*	 * The value of opts may have changed so we always	 * do the opts check.	 */  	if (IS_ON(opts, DO_NUMCHKGROUP)) { 		(void) sprintf(buf, ":%d", gid);		return(buf);  	}	/*	 * Try to avoid getgrgid() call.	 */	if (lastgid == gid && buf[0] && buf[0] != ':')		return(buf);	lastgid = gid;	if ((grp = (struct group *)getgrgid(gid)) == NULL) {		message(MT_WARNING, "%s: No name for group %d", file, gid);		(void) sprintf(buf, ":%d", gid);	} else		(void) strcpy(buf, grp->gr_name);	return(buf);}