C-API Functions

The C-API provides access to the HPOM Message Stream Interface (MSI). This interface makes it possible to read HPOM messages from the internal message stream and to write messages into the internal message stream. The MSI is available on HPOM managed nodes. All MSI types establish a connection to the HPOM message agent.

The HPOM Message Stream Interface is divided into the following types:

• OPCSVIF_EXTMSGPROC_READ

  This interface type is used for non-destructive read operations on the HPOM internal message flow. Only messages that are allowed to be output on the Agent MSI are accessible using this interface type. This type of interface is typically used by statistical analysis tools or additional display facilities.

• OPCSVIF_EXTMSGPROC_READWRITE

  This interface type is used to read messages from the internal message flow of HPOM, to create or modify messages, and to write them back to the HPOM processes. Only messages that can be output on the MSI are accessible using this interface type. Messages tagged with "copy to" remain in the HPOM message flow. Messages tagged with "divert to" are taken out of the flow. This type of interface can be used by event correlation engines.

• OPCSVIF_EXTMSGPROC_WRITE

  Interface instances of this type are used by write-only applications to feed messages into the HPOM message flow. This type of interface can also be used to encapsulate the opcif_write() routine in a command-line interface.

Prerequisites

The API functions must be issued by the agent user.

Multithread Usage

All functions of the C-API are safe to be called by multi-threaded applications. They are thread-safe for both POSIX Threads and DCE User Threads. They are not async-cancel, async-signal, or fork-safe. They cannot be called safely in kernel threads.

The opcreg_copy() routine is not thread-safe for POSIX threads or for DCE User Threads.

Registration Conditions

HPOM provides a user-accessible data type to define registration conditions as the mechanism to register with the HPOM Interfaces.

HPOM provides a set of APIs to create an empty condition, modify or query condition fields and to duplicate or delete a condition definition from memory.

Related Topics:

• C-API Security