Many of the subclasses
of IccResource have 'read' methods that return const IccBuf references; for example, IccFile::readRecord, IccTempStore::readItem and IccTerminal::receive.
Care should be taken if you choose to maintain a reference
to the
IccBuf object, rather than copy the data from the
IccBuf reference into your own
IccBuf object. For example,
consider the following
IccBuf buf(50);
IccTempStore store("TEMPSTOR");
buf = store.readNextItem();
Here, the data in the
IccBuf reference returned
from
IccTempStore::readNextItem is
immediately copied into the application's own
IccBuf object, so it does
not matter if the data is later invalidated. However, the application
might look like this
IccTempStore store("TEMPSTOR");
const IccBuf& buf = store.readNextItem();
Here, the IccBuf reference returned from IccTempStore::readNextItem is not copied into the application's own storage and
care must therefore be taken.
Note: You are recommended not to use this style of programming
to avoid using a reference to an IccBuf object that does not
contain valid data.
The returned
IccBuf reference typically contains
valid data until one of the following conditions is met:
- Another 'read' method is invoked on the IccResource object
(for example, another readNextItem or readItem method
in the example).
- The resource updates are committed (see method IccTask::commitUOW).
- The task ends (normally or abnormally).
Last updated: Thursday, 27 June 2019