unsigned int
mysql_stmt_errno(MYSQL_STMT *stmt)
          For the statement specified by stmt,
          mysql_stmt_errno() returns the
          error code for the most recently invoked statement API
          function that can succeed or fail. A return value of zero
          means that no error occurred. Client error message numbers are
          listed in the MySQL errmsg.h header file.
          Server error message numbers are listed in
          mysqld_error.h. Errors also are listed at
          Error Messages and Common Problems.
        
          If the failed statement API function was
          mysql_stmt_close(), do not
          call or mysql_stmt_errno() to
          obtain error information because
          mysql_stmt_close() makes the
          statement handler invalid. Call
          mysql_errno() instead.