niSwitch_GetAttributeViReal64

Specific Function

C Function Prototype

ViStatus niSwitch_GetAttributeViReal64 (ViSession vi, ViConstString channelName, ViAttr attributeID, ViReal64* attributeValue);

Purpose

Queries the value of a ViReal64 attribute. You can use this function to get the values of instrument specific attributes and inherent IVI attributes. If the attribute represents an instrument state, this function performs instrument I/O in the following cases:

• State caching is disabled for the entire session or for the particular attribute.
• State caching is enabled and the currently cached value is invalid.

Parameters

Name	Type	Description
vi	ViSession	A particular NI-SWITCH session established with niSwitch_InitWithTopology, niSwitch_InitWithOptions, or niSwitch_init and used for all subsequent NI-SWITCH calls.
channelName	ViConstString	Some attributes are unique for each channel. For these, pass the name of the channel. Other attributes are unique for each switch. Pass VI_NULL or an empty string for this parameter. The default value is an empty string.
attributeID	ViAttr	Pass the ID of an attribute. From the function panel window in LabWindows/CVI, you can use this control as follows. Click on the control or press <ENTER>, <spacebar>, or <ctrl-down arrow>, to display a dialog box containing a hierarchical list of the available attributes. Attributes whose value cannot be set are dim. Help text is shown for each attribute. Select an attribute by double-clicking on it or by selecting it and then pressing <ENTER>. A ring control at the top of the dialog box allows you to see all IVI attributes or only the attributes of the ViInt32 type. If you choose to see all IVI attributes, the data types appear to the right of the attribute names in the list box. The data types that are not consistent with this function are dim. If you select an attribute data type that is dim, LabWindows/CVI transfers you to the function panel for the corresponding function that is consistent with the data type. If you want to enter a variable name, press <CTRL-T> to change this ring control to a manual input box. If the attribute in this ring control has constants as valid values, you can view the constants by moving to the Attribute Value control and pressing <ENTER>.
attributeValue	ViReal64	Returns the current value of the attribute. Pass the address of a ViReal64 variable. From the function panel window in LabWindows/CVI, you can use this control as follows. If the attribute currently showing in the Attribute ID ring control has constants as valid values, you can view a list of the constants by pressing <ENTER> on this control. Select a value by double-clicking on it or by selecting it and then pressing <ENTER>.