When to release a Sequence File

Question

(ref. I'm trying to build my own operator interface in C++)
When I get a reference to a SequenceFile object I have to release this object when I'm done.
But If I AddRef the SequenceFile object before releasing it a first call to the ReleaseSequenceFile method should not actually release it, should it, It should do the actual release when I call the function for the second time.
This is my understanding from the teststand activex help reference, however when trying this, it does not work...the sequence file gets released the first time ?
can anybody help me out, maybe I'm doing something wrong here.
here's my code:
tsSequenceFile1.AttachDispatch( m_Engine.GetSequenceFile(strSequenceFile, TS_GetSeqFile_OperatorInterfaceFlags), TRUE);
tsSequenceFile1.m_lpDispatch->AddRef();
tsSequenceFile2.AttachDispatch(tsSequenceFile1.m_lpDispatch, FALSE);
now releasing it twice...
m_Engine.ReleaseSequenceFile(tsSequenceFile1.m_lpDispatch);
// release sequence file
tsSequenceFile1.ReleaseDispatch();
m_Engine.ReleaseSequenceFile(tsSequenceFile2.m_lpDispatch);
// release sequence file
tsSequenceFile2.ReleaseDispatch();
The second releaseSequenceFile, gives me the error message that the specified
sequence file is already been unloaded by the engine.
regards

Answer 1

Adding a reference to an ActiveX object never makes a new copy of the object. The ActiveX object must offer some explicit method of duplicating it. In TestStand, this method is PropertyObject.Clone.
Unfortunately, cloning a SequenceFile has a couple of wrinkles that don't arise for other object types.
1) Before TestStand 2.0.1, you could not save a cloned sequence file.
2) You cannot run a cloned file unless you first "load" the clone. Currently, the only way to "load" the clone is to save it or use GetSequenceFile to load it. Since you can't call GetSequenceFile on the clone until you have saved it, either method requires TestStand 2.0.1. I have attached an example 2.0.1 sequence which clones a sequence file object and then saves th
e clone in order to "load" it so it can run. Please read the description of the label step for more information. If you don't have a beta copy of 2.0.1, the only way I can think of to clone a SequenceFile object (and still be able to run the clone) is to call a file system function to copy the disk file to a new name and then load the new file.
- James
PS. You could probably avoid both wrinkles by writing your own sequence file cloning function that creates a new sequence file and inserts clones of the sequences and variables from the original file. It would also have to copy over all the property settings you need. Note that I haven't tried this.
Attachments:
fileclone.seq ‏27 KB