I tried the following commands, and root exited without any warnings and erros.:
root  f=new TFile(“monitor.root”)
root  mon=(TTree *)f->Get(“monitor”)
root  mon->Draw(“phm:psdm”)
Then I tried “gdb root.exe” with above commands, I got this error from GDB while root terminated:
Cannot find user-level thread for LWP 20457: generic error
What does this error mean? I have no idea about it. Please give me some hints.