niFgen_SetAttributeViString
ViStatus niFgen_SetAttributeViString (ViSession vi, ViConstString channelName, ViAttr attributeID, ViConstString attributeValue);
Purpose
Sets the value of a ViString attribute.
This is a low-level function that you can use to set 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 or is different than the value you specify.
NI-FGEN contains high-level functions that set most of the instrument attributes. It is best to use the high-level driver functions as much as possible. They handle order dependencies and multithread locking for you. In addition, they perform status checking only after setting all of the attributes. In contrast, when you set multiple attributes using the Set Attribute 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. vi is obtained from the niFgen_init or the niFgen_InitWithOptions functions and identifies a particular instrument session. | ||
| channelName | ViConstString | Specifies the name of the channel on which to check the attribute value if the attribute is channel-based. If the attribute is not channel-based, then pass VI_NULL or an empty string ("").
Default Value: "" (empty string) |
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| attributeID | ViAttr | Specifies the ID of an attribute. | ||
| attributeValue | ViInt32 | Specifies the value to which you want to set the attribute.
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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. You can examine the status code from each call to an NI-FGEN function to determine if an error occurred.
To obtain a text description of the status code, call the niFgen_error_message function. To obtain additional information about the error condition, call the niFgen_GetError function. To clear the error information from NI-FGEN, call the niFgen_ClearError function. The general meaning of the status code is as follows:
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