Postgresql ODBC driver not found

It is here I see it/them with:

odbcinst -q -d

but not with :

   SQLHENV env;
   SQLCHAR driver[256];
   SQLCHAR attr[256];
   SQLSMALLINT driver_ret;
   SQLSMALLINT attr_ret;
   SQLUSMALLINT direction;
   SQLRETURN ret;
   SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &env);
   SQLSetEnvAttr(env, SQL_ATTR_ODBC_VERSION, (void *) SQL_OV_ODBC3, 0);

   direction = SQL_FETCH_FIRST;
   while(SQL_SUCCEEDED(ret = SQLDrivers(env, direction,
                                        driver, sizeof(driver), &driver_ret,
                                        attr, sizeof(attr), &attr_ret))) {
     direction = SQL_FETCH_NEXT;
     printf("%s - %s\n", driver, attr);
     if (ret == SQL_SUCCESS_WITH_INFO) printf("\tdata truncation\n");
   }

What do I miss...?

(under debian bulllseye linked with libodbc)

Thanks in advance

PC