Functions

The HCD application programming interface provides the functions described in Table 1. The functions are listed as you need them while requesting data from the HCD HOM services. The constants you have to specify for HRB_FUNCTION and HRB_OBJ_CODE are included in the figure.
Table 1. Functions provided by the HOM services
Task Fields in Request Block (HRB) Explanation
HRB_FUNCTION= HRB_OBJ_CODE=
1. Set up the connection to the HCD API
Setup connection HRB_SETUP HRB_HCD Establish the HCD environment by passing the setup function in the request block. Input: HCD session interface (HSI) record.
2. Open the IODF
Open IODF HRB_OPEN HRB_IODF Open an IODF, for which you have read authority, by passing the HRB_OPEN function in the request block.
3. Request data for HCD objects
Get Processor HRB_GET HRB_PROCESSOR Issue a request with the GET function to retrieve data from the IODF. The request returns the address and the length of the data output block. Issue a request with the HRB_DGET function to obtain the retrieved information.
Note: Issue HRB_GET and HRB_MGET before requesting additional data, because the new request deletes all data and messages from the previous request.
Get Channel Subsystem HRB_GET HRB_CSS
Get Channel Path HRB_GET HRB_CHANNEL
Get Switch HRB_GET HRB_SWITCH
Get Physical Control Unit HRB_GET HRB_PCU
Get Device HRB_GET HRB_DEVICE
Get Activation Status HRB_ACT_STATUS HRB_IODF The request allows you to identify the currently active IODF, processor, and so on. Output: Activation status interface (ASI) record.
4. Get the data from the previous GET request
Data Get HRB_DGET HRB_DATA Issue the request with the address and length of the output area to obtain the data retrieved with the previous GET function. Output: Interface record for the object.
Message Get HRB_MGET HRB_MESSAGE Check the return and reason code of the previous GET request. If the return code is warning, error, or severe, issue the request with the address and length of the output area to obtain the messages.

Output: Message interface (MSI) record.

5. Close the IODF
Close IODF HRB_CLOSE HRB_IODF When you do not need the IODF anymore, close the IODF by issuing a request with the close function.
6. Terminate the connection to the HCD API
Terminate connection HRB_TERMINATE HRB_HCD When you do not need the HOM services anymore, terminate the connection by issuing a request with the terminate function.