Reading TTask derived class from file and fTasks

ROOT
1

I am writing a class derived from the TTask class. I plan to overwrite Write() so that the TList data member, fTasks, and its objects are is written with one key.

Can I code the default constructor is such a way that fTasks will initalize containing all the saved objects(in order) and still use the ROOT I/O?
I know that the default contructor cannot allocate memory, but I am uncertain as to how the TList and its objects work when written with a single key.

Let me know if, and why, this is a stupid question.

2

Okay, I know why its stupid; the default constructor doesn’t need to do this.

Let me reform the question. If I use:

TFile f(filename,“READ”);
MyTTaskDerivedObject *blah=f->Get(MyTTaskDerivedObjectsNameInFile);

What will blah->GetListOfTasks() have in it?
Nothing? Will the Objects be in order?

3

The objects in a list are streamed/serialized in the order found in the list.
Same when reading.

Rene

4

Thanks Rene.
If the keys are written individually does the TList still load the objects?
What happens if another program overwrites the object but not the list?

5

If you write the objects individually, you have to read them individually.

Rene