90 lines
2.2 KiB
Markdown
90 lines
2.2 KiB
Markdown
Release 4.0 IN DEVELOPMENT
|
|
===========
|
|
|
|
The main changes since release 3.0.2 are:
|
|
|
|
* array semantics now enforce Copy On Write.
|
|
* String no longer defined.
|
|
* timeStamp and valueAlarm name changes
|
|
* toString replaced by stream I/O
|
|
* union is new type.
|
|
* copy is new.
|
|
* monitorPlugin is new.
|
|
|
|
New Semantics for Arrays
|
|
--------
|
|
|
|
PVScalarArray, PVStructureArray, and PVUnionArray all enforce COW (Copy On Write) Semantics.
|
|
In order to limit memory usage the storage for raw data is managed via a new shared_vector facility.
|
|
This allows multiple instances of array data to use the shared raw data.
|
|
COW is implemented via shared_vectors of const data, i. e. data that can not be modified.
|
|
|
|
|
|
String no longer defined
|
|
---------
|
|
|
|
This is replaced by std::string.
|
|
|
|
|
|
timeStamp and valueAlarm name changes
|
|
--------------
|
|
|
|
In timeStamp nanoSeconds is changed to nanoseconds.
|
|
|
|
In valueAlarm hystersis is changed to hysteresis
|
|
|
|
|
|
toString replaced by stream I/O
|
|
---------
|
|
|
|
pvData.h and pvIntrospect no longer defines toString
|
|
Instead they have stream support.
|
|
pvIntrospect uses method dump and pvData uses dumpValue.
|
|
For example:
|
|
|
|
PVDoublePtr pvValue;
|
|
String buffer;
|
|
pvValue->toString(&buffer);
|
|
cout << buffer << endl;
|
|
buffer.clear();
|
|
pvValue->getField()->toString(&buffer);
|
|
cout << buffer << evdl;
|
|
|
|
is replaced by
|
|
|
|
PVDoublePtr pvValue;
|
|
cout << *pvValue << endl
|
|
cout << *pvValue->getField() << endl;
|
|
|
|
|
|
union is a new basic type.
|
|
------------
|
|
|
|
There are two new basic types: union_t and unionArray.
|
|
|
|
A union is like a structure that has a single subfield.
|
|
There are two flavors:
|
|
|
|
* <b>varient union</b> The field can have any type.
|
|
* <b>union</b> The field can any of specified set of types.
|
|
|
|
The field type can be dynamically changed.
|
|
|
|
copy
|
|
----
|
|
|
|
This consists of createRequest and pvCopy.
|
|
createRequest was moved from pvAccess to here.
|
|
pvCopy is moved from pvDatabaseCPP and now depends
|
|
only on pvData, i. e. it no longer has any knowledge of PVRecord.
|
|
|
|
monitorPlugin
|
|
-------------
|
|
|
|
This is for is for use by code that implements pvAccess monitors.
|
|
This is prototype and is subject to debate.
|
|
|
|
Release 3.0.2
|
|
==========
|
|
This was the starting point for RELEASE_NOTES
|