Gcc to compile root macro -> 'undefined reference to' error

ROOT
1

Dear rooters,

I’m trying to use g++ directly to compile my code and produce a stand-alone executable. Unfortunately I have run into an issue I don’t know how to solve. This is what I’m doing with my code:

g++ lvis_mol_lens.cxx read_inputs.cxx -o lvis_mol_lens -Wall -I /opt/root/include/root/ -L /opt/root/lib/root/

After this I’m getting this type of output:

/tmp/ccDvSTwe.o: In function `main':
lvis_mol_lens.cxx:(.text+0x37a1): undefined reference to `TVector3::TVector3(double, double, double)'
lvis_mol_lens.cxx:(.text+0x3828): undefined reference to `TVector3::TVector3(double, double, double)'
lvis_mol_lens.cxx:(.text+0x38a3): undefined reference to `TRotation::TRotation()'
lvis_mol_lens.cxx:(.text+0x3924): undefined reference to `TRotation::TRotation()'
lvis_mol_lens.cxx:(.text+0x3a55): undefined reference to `TVector3::SetTheta(double)'
lvis_mol_lens.cxx:(.text+0x3a9c): undefined reference to `TVector3::SetPhi(double)'
lvis_mol_lens.cxx:(.text+0x3aef): undefined reference to `TVector3::SetPhi(double)'
lvis_mol_lens.cxx:(.text+0x3b23): undefined reference to `TVector3::Unit() const'
....

Despite the fact the output doesn’t point to any line in particular, I’m certain the first few errors correspond to the following part in my code

....
	TVector3 kmol[4];					// Wavevectors molasses

	TVector3 w0molpos[4];				// Molasses beam waist position from center molasses reference frame

	TRotation molrotz[4];				// Rotations to transform from center molasses reference frame to beam frame

	TRotation molrotx[4];

	double molwidth = 0;					// Average beam width at molasses center

	int i;

	for ( i = 0 ; i < nmolbeams ; i ++ )
	{
		kmol[i].SetX( 1 );

		kmol[i].SetMag( 1 / lam );

		kmol[i].SetTheta( pi / 2 );

		if ( i < 2 )

			kmol[i].SetPhi( i * pi );

		else

			kmol[i].SetPhi( ( 2 * i - 3 ) * pi / 2 );

		w0molpos[i] = - kmol[i].Unit();

....

My gut feeling is: “this is me not understand C++”

Please help!, any nudge in the right direction is greatly appreciated!

Thanks

2

Hi,

You would need to link your executable against the ROOT library that you are using, so in your case:`root-config --libs` -lPhysics(the call to root-config is to get the list of default ROOT library).

Cheers,
Philippe.

3

[quote=“pcanal”]Hi,

You would need to link your executable against the ROOT library that you are using, so in your case:`root-config --libs` -lPhysics(the call to root-config is to get the list of default ROOT library).

Cheers,
Philippe.[/quote]

Thanks!, this helped a lot, but it is not clear (from the list below) what should I use for the geometry library?

$ root-config --libs
-L/opt/root/lib/root -lCore -lCint -lRIO -lNet -lHist -lGraf -lGraf3d -lGpad -lTree -lRint -lPostscript -lMatrix -lPhysics -lMathCore -lThread -lz -pthread -lm -ldl -rdynamic
4

Hi,

-lGeom ? In the reference guide (see for example root.cern.ch/root/html/TGeoBBox.html) you can see the library name in the box in the top right of the page.

Cheer,s
Philippe.

5

[quote=“pcanal”]Hi,

-lGeom ? In the reference guide (see for example root.cern.ch/root/html/TGeoBBox.html) you can see the library name in the box in the top right of the page.

Cheer,s
Philippe.[/quote]

I see. Thanks again.