Adding a new package

TOBE updated

It is possible to write a code based on REST and compile it. We can make a library which extends functionality to REST mainbody, or we can make an executable calling REST classes.

In the directory ./packages/userRESTLibrary, we have a library project which can directly be compiled.

~/REST_v2$ cd packages/userRESTLibrary
~/REST_v2/packages/userRESTLibrary$ mkdir build
~/REST_v2/packages/userRESTLibrary$ cd build
~/REST_v2/packages/userRESTLibrary/build$ cmake ..
~/REST_v2/packages/userRESTLibrary/build$ make install

The default installation path of this project is “userRESTLibrary/lib”. If we add this to our LD_LIBRARY_PATH:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$HOME/REST_v2/packages/userRESTLibrary/lib

Then REST will load this library at its startup, new classes in it will be available.

To build our own executable based on REST, we can take a look at restG4. To use REST classes we just need to include corresponding headers. To use reflection functionalities we need to dynamically load REST libraries in the program. For example:

//in file test.cxx

#include "TRestRun.h"`  
#include "TRestGas.h"`  

int main(int argc, char *argv[]) {  

	TRestTools::LoadRESTLibrary(true);
	TRestRun *run = new TRestRun();
	run->OpenInputFile("abc.root");
	TRestGas *gas = (TRestGas *)run->GetMetadataClass("TRestGas");
	gas->InitFromRootFile();
	cout<<gas->GetDriftVelocity(70)<<endl;

}  

If we remove the 4th line, there will be a warning message from TRestGas telling us REST cannot use gas utility. Because the gas library needs to be dynamically loaded.

Note that this source file uses only REST and ROOT6. Such file can be compiled into library/executable with a single command:

library: gcc test.cxx -std=c++11 -I`root-config --incdir` -I`rest-config --incdir rest-config --libs` `root-config --libs` -lGui -lEve -lGeom -lMathMore -lGdml -lMinuit
-L/usr/lib64 -lstdc++ -shared -fPIC -o test.so
executable: gcc test.cxx -std=c++11 -I`root-config --incdir` -I`rest-config --incdir rest-config --libs` `root-config --libs` -lGui -lEve -lGeom -lMathMore -lGdml -lMinuit
-L/usr/lib64 -lstdc++ -fPIC -o test

Adding a new package

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