The documentation should specify more explicitly is the return value for this function:

I’m pretty sure the return value is the same pointer as the 2nd argument, when passed a TH1*, or the pointer to the TH1* created when that argument is left out, but the documentation doesn’t say.


After having read (or tried to read) the documentation for the rest of TVirtualFFT, I must say this particular TH1 method’s documentation is not that bad. Maybe a general “improve documentation for TVirtualFFT” ticket would be appropriate.