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pvxs/documentation/nt.rst
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.. _ntapi:
Common Type Definitions
=======================
Library of common type definitions. ::
#include <pvxs/nt.h>
namespace pvxs { namespace nt { ... } }
.. toctree::
:maxdepth: 1
:caption: Contents:
ntscalar
.. note::
The nt::* factories are expensive. Avoid repeated use with `pvxs::Value::cloneEmpty`.
.. _time_t:
time_t
------
Commonly used sub-structure to represent a time
**"secondsPastEpoch"**
Seconds since POSIX epoch of 1 Jan 1970 UTC.
Note that the EPICS epoch is 631152000 seconds after the POSIX epoch.
(cf. POSIX_TIME_AT_EPICS_EPOCH in epicsTime.h from EPICS Base)
**"nanoseconds"**
Number of nanoseconds since the start of the second.
.. _alarm_t:
alarm_t
-------
**"severity"**
Enumeration of 0 - No Alarm, 1 - Minor, 2 - Major, 3 - Invalid.
The meaning of Minor and Major are contextual and may be different for each PV.
An Invalid alarm severity means that the value field should not be taken as
a meaningful represention of eg. the quantity being measured. Typically,
it reflects the most recent valid value.
A UI client may change the state of a widget displaying a value which is alarming
by eg. changing border color.
**"status"**
Enumeration providing context to **"severity"** 0 - No Alarm, 1 - Device, 2 - Driver,
3 - Record, 4 - Database, 5 - Configuration, 6 - Undefined, 7 - Client
**"message"**
Arbitrary string describing the condition being alarmed.
NTNDArray
---------
Container for image data used by areaDetector.
.. doxygenstruct:: pvxs::nt::NTNDArray
:members:
NTURI
-----
.. doxygenclass:: pvxs::nt::NTURI
:members: