Attribute State Caching Editor

Nimbus allows state caching to be enabled on an attribute-by-attribute basis. The Attribute State Caching Editor allows the driver developer to enable or disable state caching for the selected attribute and to specify cache couplings. See the topic Understanding State Caching for more information.

Important

The state caching logic specified here is only executed when state caching is enabled by the end user. This can be done by passing Cache=VI_TRUE as part of the OptionString parameter to the driver’s InitWithOptions function, or it can be done after driver initialization via the CACHE attribute.

Enable caching of this attribute

When checked, Nimbus will generate code in the attribute getter and setter preamble sections that caches the attribute value between calls. This can reduce I/O traffic if redundant calls to the attribute occur, but it can also lead to cache coherency issues (data in memory out-of-sync with the actual instrument settings) if the property couplings are not thoroughly understood and properly specified.

Attributes invalidated when this attribute is set

This list contains the names of any cached attributes that will be invalidated whenever this attribute is set. Invoking the attribute setter will cause any previously cached values corresponding to the specified attributes to be discarded.

To add an attribute to the invalidation list

1. Click in the first available entry of the list.

2. Enter an attribute name, without the driver PREFIX_ATTR_ portion. For example, for an attribute with a full attribute ID of ACME4321_ATTR_TRIGGER_SOURCE, only the string TRIGGER_SOURCE would be entered here.

3. Press the enter key.

To remove an attribute from the invalidation list

1. Click on the row selector to the left of a attribute name.

2. Press the delete key.

See also

• Adding Functionality to an IVI-C Driver
• Understanding State Caching