viSetAttribute

Syntax

viSetAttribute(ViSession/ViEvent/ViFindList vi, ViAttr attribute, ViAttrState attrState);

Description

This function sets the state of an attribute for the specified session. The viSetAttribute operation is used to modify the state of an attribute for the specified session, event, or find list.

If a resource cannot set an optional attribute state and the specified attribute state is valid and the attribute description does not specify otherwise, viSetAttribute returns error code VI_ERROR_NSUP_ATTR_STATE.

Both VI_WARN_NSUP_ATTR_STATE and VI_ERROR_NSUP_ATTR_STATE indicate that the specified attribute state is not supported. Unless a specific rule states otherwise, a resource normally returns the error code VI_ERROR_NSUP_ATTR_STATE when it cannot set a specified attribute state. The completion code VI_WARN_NSUP_ATTR_STATE is intended to alert the application that although the specified optional attribute state is not supported, the application should not fail.

One example is attempting to set an attribute value that would increase performance speeds. This is different than attempting to set an attribute value that specifies required but nonexistent hardware (such as specifying a VXI ECL trigger line when no hardware support exists) or a value that would change assumptions a resource might make about the way data is stored or formatted (such as byte order). See specific attribute descriptions for text that allows the completion code VI_WARN_NSUP_ATTR_STATE.

The error code VI_ERROR_RSRC_LOCKED is returned only if the specified attribute is read/write and global, and the resource is locked by another session.

Parameters

Name	Dir	Type	Description
vi	IN	ViSession ViEvent ViFindList	Unique logical identifier to a session, event, or find list.
attribute	IN	ViAttr	Resource attribute for which the state is modified.
attrState	IN	ViAttrState	The state of the attribute to be set for the specified resource. The interpretation of the individual attribute value is defined by the resource.

Return Values 

Type ViStatus	This is the function return status. It returns either a completion code or an error code as follows.
Completion Code	Description
VI_SUCCESS	Attribute value set successfully.
VI_WARN_NSUP_ATTR_STATE	Although the specified attribute state is valid, it is not supported by this resource implementation. (The application will still work, but this may have a performance impact.)
Error Code	Description
VI_ERROR_ATTR_READONLY	The specified attribute is read-only.
VI_ERROR_INV_SESSION VI_ERROR_INV_OBJECT	The given session or object reference is invalid (both are the same value).
VI_ERROR_NSUP_ATTR	The specified attribute is not defined by the referenced resource.
VI_ERROR_NSUP_ATTR_STATE	The specified state of the attribute is not valid, or is not supported as defined by the resource. (The application probably will not work if this error is returned.)
VI_ERROR_RSRC_LOCKED	Specified operation could not be performed because the resource identified by vi has been locked for this kind of access.

See Also

viGetAttribute. See VISA Resource Classes for a list of attributes and attribute values.