I’d like to use the TMapFile to create a memory mapped file and show them with TApplication as an online monitoring for data taking. With ROOT 6.12.06 on Ubuntu 16.04.7 LTS the concept worked very smoothly. However after the system upgraded as well as newer ROOT installed this features doesn’t work any more.
To find out what is going on, I have tried many combinations of ROOT versions (ROOT 6.12 to 6.28) and variable Operating system (e.g., Ubuntu 18.04, 20.04 etc.). At the end, it turns out that none of those combinations works. To make the problem reproducible I used the ROOT tutorial macros, e.g. hisprod.C and hisplot.C demonstrating how TMapFile works as well as the appdemo.C showing the TApplication features.
Meanwhile I also searched the previous discussion in ROOT forum about both topics. It seems that the problem remains with the TMapFile with newer ROOT versions. Even compiling the TMapFile macros with -lNew, it still returns the same error messages. With an older ROOT version, for instance ROOT 6.12.06 on a newer operating system (error may occur when compiling this ROOT version), TMapFile works properly but TApplication crashes due to segmentation violation. The situation restricted us to use the online monitoring feature for our experiment. Could anybody look at this issue and may find a solution to this?
The detailed information including the macros have been uploaded to github of ROOT project. Here is the link,
One could download the macros to reproduce the problem described above. Many thanks in advance.