/* change_user(user=nil, passwd=nil, db=nil) */
static VALUE change_user(int argc, VALUE* argv, VALUE obj)
{
VALUE user, passwd, db;
char *u, *p, *d;
MYSQL* m = GetHandler(obj);
rb_scan_args(argc, argv, "03", &user, &passwd, &db);
u = NILorSTRING(user);
p = NILorSTRING(passwd);
d = NILorSTRING(db);
if (mysql_change_user(m, u, p, d) != 0)
mysql_raise(m);
return obj;
}