How to invoke the HOM services
Programs can invoke the services from the HCD routine CBDMGHOM. An application
issuing a request must have its own copy of the CBDMGHOM routine dynamically
loaded or linked. For every request, the application must use the same HRB address
for each call to CBDMGHOM and must pass the parameters
shown in Table 32 using standard linkage conventions.
Table 32. Used registers and passed parameters| Register | Contents |
|---|
| 0 | Undefined | | 1 | Address of five-word parameter list:
- Address of request control block (HRB)
4-byte
field containing the address of the request block. The request block contains
the function, the object to which the function is applied, and qualifiers,
attributes, and parameters. See Request block (HRB) for more details.
- Address of (pointer to input data or zero)
4-byte
field containing the address of the address of the data input block if the
request requires input. It is required on a HRB_SETUP request. See Data input and output areas for more details.
- Address of (length of input data or zero)
4-byte
field containing the address of the fullword fixed binary integer containing
the length of the input data. It must correspond to the exact length of the
data contained in the data-input block, that is, no trailing or intermediate
blanks are allowed.
- Address of (pointer to output data or zero)
4-byte field containing the address of the address of the data output block
if the request returned output. It is required on HRB_DGET and HRB_MGET requests
to obtain the data and messages from the API. See Data input and output areas for
more details.
- Address of (length of output data or zero)
4-byte
field containing the address of the fullword fixed binary integer containing
the length of the output data.
The parameters must be coded in the order shown. Only the first parameter
(address of request block) is mandatory. The others are optional and depend
on the type of request, as shown in Figure 211. If you omit an
optional parameter, you must specify a zero instead. | | 2-12 | Undefined | | 13 | Address of 18 word save area | | 14 | Return address | | 15 | Entry point address |
Note:
The service supports calls for both 24-bit and 31-bit addressing
mode.
|
z/OS HCD User's Guide
Copyright IBM Corporation 1990, 2014