Fill an identical histogram from separate programs

Dear ROOT developers and users,

Is it possible to fill an identical histogram from multiple programs running separately,
and write it on an identical file?
Does it use thread technique?
I would appreciate it if you refer me to an example, if any.


The solution is to create the histogram in each process/job,
then store it into one file per process/job.
In the last step you use $ROOTSYS/hadd to merge your files containing one or more histograms into one single file.


Hi, Rene,
thank you for the reply.

I didn’t know the presence of “hadd” command.
I’ll try it.