Program-to-Program Interface › Interface Details

Interface Details

A brief overview of the interface follows.

• Programs construct a request parameter block (RPB) that contains details about a call to PPI.
• A program then issues a CALL to CNMNETV (CNMNETM), passing the RPB as the only parameter (standard linkage, R1 pointing to the word containing the RPB address).
• Upon return, the RC field in the RPB contains the return code. Depending on the call and the return code, other data can be provided.

  For more information about the correlation between the &ZFDBK and &RETCODE system variables, see the &PPI verb description in the Network Control Language Reference Guide.

The following functions can be provided in the RPB function code field:

Function code 1-inquire about PPI status

This function code allows an application program to determine if PPI is available and active in the system. A return code of 10 indicates that it is available.

Function code 2-obtain receiver status

This function code allows an application program to determine the status of a named receiver program. Return codes indicate whether the receiver is defined or not, and whether it is presently active or not.

Function code 3-obtain ASCB and TCB addresses

This function code allows programs written in languages that do not support the ability to obtain ASCB or TCB addresses, the addresses of these control blocks. They are needed for other PPI calls.

Function code 4-define and initialize receiver

This function code allows a program to define itself as a receiver. The program provides a unique 1 to 8 character receiver name and queue limit. Following this call, the receiver is defined, and other programs can send data to it.

The receiver can optionally be defined as authorized. This prevents programs that are not APF authorized from sending data to it.

Function code 9-deactivate a receiver

This function code allows a defined receiver program to deactivate itself. The queue limit can be optionally altered. If a receiver program (Task) terminates without issuing this call, it is automatically deactivated.

Function code 12-send a generic alert

This function code allows any program to send a generic alert to your product. It is sent to the defined receiver NETVALET, which receives these generic alerts in NMVT format, and forwards them on to NEWS.

Function code 14-send a data buffer

This function code allows any program to send a data buffer to any defined receiver (active or inactive). The receiver will be notified if necessary.

Function code 22-receive a data buffer

The function code allows a receiver program to receive the next available data buffer. If no buffers are available, a return code informs the receiver.

Function code 24-wait on an ECB

This function code allows a program written in a language that does not support ECB waiting, to wait for data to arrive.

Function code 60-obtain a unique name

This function code, available only in this implementation of PPI, allows a program to obtain a unique 8 character ID. Although programs that only send data need not have a unique ID, all receivers must have a unique ID. This service is provided to allow a sender to obtain a unique ID so that it can register itself as a receiver for a two-way conversation.