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