Application programs running on an MCP host system can send any arbitrary message string to Operations Sentinel by way of the API library included with the interface software.

See Section 7 for a description of the API library and how to use it. This section describes event messages that can be produced when using the API.

Message Formats

When an application program uses the API library to send a message to Operations Sentinel, the API library formats the message string and sends it to the interface software on the MCP host. The interface then sends it to the Operations Sentinel server.

This is the format of the message received at the Operations Sentinel server:

mixnum application–program–name			 message–string

When an application program links to the API library, the following message is sent to the Operations Sentinel server:

mixnum application–program–name				LINKED TO API

When an application program unlinks (disconnects) from the API library, the following message is sent to the Operations Sentinel server:

mixnum application–program–name			UNLINKED FROM API

When the API library detects that an application program’s heartbeat timer has expired, one of the following messages is sent to the Operations Sentinel server depending on the condition that caused the timer to elapse. In these messages, appl–id is the application identifier returned by the LINK_APPL_PROGRAM procedure, described in 7.2.

appl–id application–program–name		HEARTBEAT TIMER EXPIRED
appl–id application–program–name		APPLICATION TERMINATED WITHOUT UNLINKING

The API library sends the following message to the Operations Sentinel server when it receives a SEND_STATUS call or SEND_MESSAGE call from the application, and if the most recent message it sent to the Operations Sentinel server was HEARTBEAT TIMER EXPIRED:

appl–id application–program–name		HEARTBEAT RESUMED

This message is not sent if the application has terminated and restarted with a different mixnum value. Similarly, this message is not sent if the application's heartbeat timer has not expired since the last SEND_STATUS or SEND_MESSAGE call.