O2 Build and Rebuild

I have another problem for O2 building. It looks like every time my O2 successfully builds and I make a change to it and run aliBuild build O2 --defaults o2, it will skip building O2. But if O2 does not build and I make a change to it, it will recognize my change and go ahead to rebuild. I am not sure why this happens. I guess there may be a better way to force O2 to rebuild?

Also, can O2 be built easily? Let’s say I only want to build the Detector/ITSSMFT/ITS part, do I always need to go through the entire build process of the whole O2 software? Thank you very much

Hi Zhaozhong,

After having build once, you can do simply (the alienv should be set before invoking this)
make install

It will rebuild only modified code. You can do this also for particular module, e.g.
cd $ALICE_WORK_DIR/BUILD/O2-latest/O2/Detectors/ITSMFT/ITS
make install

in this case only modified code for this module will be recompiled (modulo its dependencies).

Hi Ruben,

Actually, there is a problem:

[szhaozho@svmithi02 O2-latest]$ make install
make: *** No rule to make target `install’. Stop.

Zhaozhong Shi

Hi @szhaozho,

Take a look at this thread: Where is the quick way to rebuild O2?