NIHSDIO_ATTR_FETCH_RELATIVE_TO
- Updated2023-02-21
- 1 minute(s) read
Specific Attribute
| Data type |
Access | Applies to | Coercion | High-Level Functions |
|---|---|---|---|---|
| ViInt32 | R/W | N/A | None | None |
Description
Specifies the absolute location within the acquired record from which to begin fetching.
This attribute is supported only for acquisition sessions.
Defined Values:
| NIHSDIO_VAL_MOST_RECENT_SAMPLE (46) | Specifies that fetching occur relative to the most recently acquired data. The fetch offset (NIHSDIO_ATTR_FETCH_OFFSET) must be negative to use this value. |
| NIHSDIO_VAL_FIRST_SAMPLE (47) | Specifies that fetching occurs at the first sample acquired by the device. If the device wraps its buffer, then the first sample is no longer available. In this case, NI-HSDIO returns an error if the fetch offset is in the overwritten data. |
| NIHSDIO_VAL_REFERENCE_TRIGGER (48) | Specifies that fetching occur relative to the Reference trigger. This value behaves like NIHSDIO_VAL_FIRST_SAMPLE if no Reference trigger is configured. |
| NIHSDIO_VAL_FIRST_PRETRIGGER_SAMPLE (49) | Specifies that fetching occur relative to the first pretrigger sample acquired. This value behaves like NIHSDIO_VAL_FIRST_SAMPLE if no Reference trigger is configured. |
| NIHSDIO_VAL_CURRENT_READ_POSITION (50) | Specifies that fetching occur after the last fetched sample. The initial read position depends on whether the Reference trigger is enabled. If the Reference trigger is disabled, the initial read position is the first sample acquired. If a Reference trigger is enabled, the initial read position is the first pretrigger sample. |