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<== Date ==> | <== Thread ==> |
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Subject: | Re: Compression record returns double value for field "N" over channel access |
From: | Ralph Lange via Core-talk <core-talk at aps.anl.gov> |
To: | EPICS Core Talk <core-talk at aps.anl.gov> |
Date: | Fri, 25 Nov 2022 11:25:43 +0100 |
The field N (and NSAM) of a compression record should according to specification (https://epics.anl.gov/base/R7-0/6-docs/compressRecord.html) use ULONG. However, reading the field N over channel access apparently may return a double value:
>cainfo RFQ-010:RFS-EPR-110:Cur-ROI-Avg.N
RFQ-010:RFS-EPR-110:Cur-ROI-Avg.N
State: connected
Host: idmz-ro-epics-gw-tn.esss.lu.se:5064
Access: read, no write
Native data type: DBF_DOUBLE
Request type: DBR_DOUBLE
Element count: 1
The assumption is that since input data is an array of doubles, the field N uses same type.
While the above suggests query was handled by a ca gateway, I get the same result when not using a gateway.
Seems pvaccess returns a unsigned long type for field N.
Is this behavior expected?