HP-UX Event ManagerProgrammer's Guide

A variable name can be made up of any combination of uppercase or lowercase alphanumeric
characters and the underscore (_) character. Names must be meaningful. The variable name is
carried inside the event. Large physical events have longer names.
A variable data item can be extracted and used directly by the subscriber, or combined with the
event format text string to produce a formatted version of the event for display.
Table 2-4 lists the variable types that EVM supports.
Table 2-4 EVM's Variable Data Types
Size and TypeType Identifier
8-bit integer
EvmTYPE_BOOLEAN
8-bit character
EvmTYPE_CHAR
16-bit signed integer
EvmTYPE_INT16
32-bit signed integer
EvmTYPE_INT32
64-bit signed integer
EvmTYPE_INT64
8-bit unsigned integer
EvmTYPE_UINT8
16-bit unsigned integer
EvmTYPE_UINT16
32-bit unsigned integer
EvmTYPE_UINT32
64-bit unsigned integer
EvmTYPE_UINT64
32-bit floating-point value
EvmTYPE_FLOAT
64-bit floating-point value
EvmTYPE_DOUBLE
Null-terminated character string
EvmTYPE_STRING
Binary data whose size must be specified explicitly
EvmTYPE_OPAQUE
In general, because variables contain information that is specific to an instance of an event, they
must be included in the event by the poster. However, for documentation purpose, it is also
useful to include variable names and types along with dummy values, in the template version
of the event. For information on templates, see “Designing Event Templates” (page 24).
Designing a Set of Events
When designing an application or a subsystem, you must also design an associated set of events.
EVM events must be designed with care. Events must meet the requirements of two format types:
the human style (readable text) and the program style (binary data). After an event is posted, it
can be viewed in text form, and an appropriate action can be taken.
Consider the following guidelines while designing an event:
1. Decide on a family name for a set of related events. For more information, see “Event Name
Data Item” (page 16)
2. Create a list of status changes that may be of interest to a monitoring entity, and choose a
name for each event. For more information about monitoring entity, see “Deciding Which
Status Changes are Eventworthy” (page 23).
3. Decide on the contents of each event. Each individual event must have a unique name. Most
events need a format string and a priority, and many events need variables. For each variable,
consider the type and possible values. For more information about EVM event content, see
“EVM Event Content” (page 15).
22 Event Manager Events