Getting error : invalid string conversion occured.

I am using psqlodbc native driver with my C++ application. I am facing errors in the below scenario.

I have a PostgreSQL database (Server character set is UTF-8, Database character set is UTF-8)

My System character set/locale is ASCII. The session character set is also ASCII.

Below is the details of the table i am using

CREATE TABLE conv_vchar (
    id SERIAL PRIMARY KEY,
    vchar_col VARCHAR(255)
);

I am inserting some characters in table varchar column which is only available in UTF-8 and not in ASCII.

The characters are "कखग".

please note that none of these characters is present in ASCII.

I have tried binding the varchar column with the below two types. Both give me the same error
1. SQL_C_BINARY

2. SQL_C_CHAR

ODBC error: SQLSTATE S1000 native database error 36. invalid string conversion occured.

Is there a correct way to bind this?

How can this be fixed?

Your help will be highly appreciated.

Regards,

Abhishek Kumar