Signature:

      SUBROUTINE h5awrite_f(attr_id, memtype_id, buf, dims, hdferr)
        INTEGER(HID_T)  , INTENT(IN)               :: attr_id
        INTEGER(HID_T)  , INTENT(IN)               :: memtype_id
        TYPE            , INTENT(IN)               :: buf
        INTEGER(HSIZE_T), INTENT(IN), DIMENSION(*) :: dims
        INTEGER         , INTENT(OUT)              :: hdferr

Inputs:

      attr_id     - Attribute identifier
      memtype_id  - Attribute datatype identifier  (in memory)
      dims        - Array to hold corresponding dimension sizes of data buffer buf;
                    dim(k) has value of the k-th dimension of buffer buf;
                    values are ignored if buf is a scalar
      buf         - Data buffer; may be a scalar or an array

Outputs:

      hdferr      - Returns 0 if successful and -1 if fails