odbc can not get the whole utf8 string

[cole lin]

I create a database with utf8:

connect mysql:

#mysql -h 192.168.26.42 -u root -p

mysql> show variables like 'collation_%';
+----------------------+-------------------+
| Variable_name | Value |
+----------------------+-------------------+
| collation_connection | utf8_general_ci |
| collation_database | utf8mb4_bin |
| collation_server | latin1_swedish_ci |
+----------------------+-------------------+
3 rows in set (0.00 sec)

then create a table:

mysql> create table test_tab(f1 int, f2 varchar(25));
Query OK, 0 rows affected (0.12 sec)

insert 1 row:
mysql> insert into test_tab values(1, "沙子沙子沙子沙子沙子");
Query OK, 1 row affected (0.02 sec)

ps:"沙子沙子沙子沙子沙子" is Chinese；

select row:
mysql> select f2 from test_tab where f1 = 1;
+--------------------------------+
| f2 |
+--------------------------------+
| 沙子沙子沙子沙子沙子 |
+--------------------------------+
1 row in set (0.00 sec)

I can get whe whole utf8 string;

##########################################
I config ODBC DSN like that:
[ssodb]
Driver=/usr/lib64/libmyodbc8w.so
SERVER=192.168.26.42
PORT=3306
Database=sso
CHARSET=UTF8

then run:
#isql ssodb root 123456 -v

select row with odbc:
SQL> select f2 from test_tab where f1 = 1;
+--------------------------+
| f2 |
+--------------------------+
| 沙子沙子沙子沙子+--------------------------+
SQLRowCount returns 1
1 rows fetched

I just can get "沙子沙子沙子沙子" but not "沙子沙子沙子沙子沙子";
How i can get the whole utf8 string with ODBC?
It seems ODBC just get 25/3 utf8 character； 25 is the size of column
f2；3 is ths utf8 character size;

ps:
unixODBC version:2.3.7/2.3.9
mysql-connector-odbc version:8.0.15/8.0.28
mysql server version:5.6.39