niRFSG_SetAttributeViSession
C Function Prototype
ViStatus niRFSG_SetAttributeViSession (ViSession vi, ViConstString channelName, ViAttr attributeID, ViSession attributeValue);
Purpose
Sets the value of a ViSession attribute.
Use this low-level function to set the values of inherent IVI attributes, class-defined attributes, and instrument-specific 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 or is different than the value you specify.
NI-RFSG contains high-level functions that set most of the instrument attributes. Use the high-level driver functions as much as possible, as they handle order dependencies and multithread locking. The high-level functions also perform status checking only after setting all of the attributes. In contrast, when you set multiple attributes using the SetAttribute functions, the functions check the instrument status after each call.
Also, when state caching is enabled, the high-level functions that configure multiple attributes perform instrument I/O only for the attributes whose value you change. Thus, you can safely call the high-level functions without the penalty of redundant instrument I/O.
Parameters
| Input | ||||
| Name | Type | Description | ||
| vi | ViSession | Identifies your instrument session. The ViSession handle is obtained from the niRFSG_init function or the niRFSG_InitWithOptions function and identifies a particular instrument session. Default Value: None |
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| channelName | ViConstString | Specifies the channel to which the attribute applies if this attribute is channel-based. If the attribute is not channel-based, set this parameter to "" (empty string) or VI_NULL. Default Value: "" (empty string) |
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| attributeID | ViAttr | Pass the ID of an attribute. | ||
| attributeValue | ViSession | Pass the value to which you want to set the attribute.
Default Value: None |
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Return Value
| Name | Type | Description | ||||||||
| status | ViStatus | Returns the status code of this operation. The status code either indicates success or describes an error or warning condition. Examine the status code from each call to an instrument driver function to determine if an error occurred.
To obtain a text description of the status code, call the niRFSG_error_message function. To obtain additional information about the error condition, call the niRFSG_GetError function. To clear the error information from the driver, call the niRFSG_ClearError function. The general meaning of the status code is as follows:
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