Can one substract one histogram by another hisogram?


I have used TSpectrum to estimate the background (say, TH1D *hb) of the spectrum (say, TH1D *h).
How can I subtract the backgroud histogram (hb) from the raw spectrum h? It might be helpful for peaking searching and fitting…

I found something in the manual. It seems that
TH1D hclean = (*h) + (hb)(-1.)
does the job… However, I am not sure and also hclean is not a pointer…

I have found a previous post, attached blow: