EvmFilterCreate(3)EvmFilterCreate(3)NAMEEvmFilterCreate(), EvmFilterDestroy(), EvmFilterIsFile(), EvmFilter‐
ReadFile(), EvmFilterSet(), EvmFilterTest() - event filter evaluator
routines
SYNOPSIS
Library
EVM Support Library
Parameters
filter_evaluator For filter_evaluator is the return handle of an estab‐
lished filter evaluator.
For filter_evaluator , identifies the filter evaluator
that uses the filter_string in subsequent matches.
For filter_evaluator identifies the filter evaluator
that compares the supplied event with the filter
string.
For filter_evaluator identifies the filter evaluator
to be destroyed.
filter_string The filter string used by the filter evaluator in sub‐
sequent matches. See the EvmFilter(5) manpage for the
syntax.
event The event to be compared with the filter string cur‐
rently associated with the filter evaluator.
matchFlag The result obtained when the supplied event is com‐
pared with the filter string currently associated with
the filter evaluator. Possible return values are as
follows:
The event matches the
filter_string.
The event does not match the
filter_string.
DESCRIPTION
The filter evaluation routines check whether an event matches a given
event filter. These functions are useful to clients that pass a com‐
plex filter to the EVM daemon. Then the clients test incoming events
against subcomponents of the filter to determine the appropriate
action.
The routine establishes an instance of a filter evaluator, returning a
handle in filter_evaluator.
The routine passes a filter_string to the filter_evaluator for subse‐
quent matches.
The routine compares the supplied event with the filter_string cur‐
rently associated with the filter_evaluator. The result is returned in
matchFlag. Possible return values are as follows:
The event matches the
filter_string.
The event does not match the
filter_string.
The indirect filter syntax, is supported by the and routines. Programs
which support indirect filters may use to determine whether a user-sup‐
plied filter string is indirect. If so, then use to expand the file to
a regular filter string.
returns if the supplied filter_string uses indirect filter notation,
and returns otherwise.
interprets the supplied filter_string, and attempts to open and read
the referenced file. returns a pointer to heap space memory containing
the expanded filter string. The caller is responsible for freeing the
memory when it is no longer needed. NULL is returned if an error
occurs while reading the file. Note that does not attempt to validate
the filter string contained in the file.
The routine destroys the filter_evaluator, freeing all associated
resources.
RETURN VALUE
The operation completed without error.
A filter string that is syntactically invalid passed to the filter
evaluator.
One of the arguments to the function is invalid.
A value in a structure member is invalid.
An operation failed because an attempt to acquire heap memory failed.
An attempt was made to use a filter evaluator without first calling
which provides an initial filter string.
An attempt to read a filter file failed.
ERRORS
The value of is not set.
SEE ALSO
Event Management
EVM(5).
EVM Events
EvmEvent(5).
Event Filter
EvmFilter(5).
EvmFilterCreate(3)