1.3 KiB
Release release/3.1 IN DEVELOPMENT
The main changes since release 3.0.2 are:
- array semantics now enforce Copy On Write.
- 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.
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:
- varient union The field can have any type.
- union 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.
Release 3.0.2
This was the starting point for RELEASE_NOTES