What to do with a TH1* from file no longer needed

[Viesturs]

Consider this example:

TFile *file = TFile::Open("file.root", "READ");
TH1 * h = (TH1*) file -> Get("histo");

If I would like to remove this histogram from the heap memory is it sufficient to do:

h -> Delete();
h = nullptr;

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[eguiraud]

Hi,
yes that should be enough, or even just delete h.

Cheers,
Enrico

[Viesturs]

what is the main difference between

delete h

and

h -> Delete()

[eguiraud]

I don’t think there is any difference in practice if the object is on the heap, @pcanal @Axel ?

If the object is on the stack, ->Delete() should still be safe (and a no-op), while you can’t call delete on a stack-allocated object.

[Axel]

Please just use delete h which works for any heap-allocated object, like those read from a TFile.