Naming Conventions and General Variables

Naming Conventions

ROOT classes begin with T
Examples: TLine, TTree
T is “Type” or “Template”, to represent classes in ROOT.

Non-class types end with _t
Example: Int_t
_t is “type”.

Data members begin with f
Example: fTree
f is “field”.

Member functions begin with a capital letter.
Example: Loop()

Constants begin with k
Examples: kInitialSize, kRed
k is Germany “konstant” (= constant).

Global variables begin with g followed by a capital letter.
Example: gEnv
g is “global”.

Static data members begin with fg
Example: fgTokenClient
fg = f + g = “field + global”, meaning both data members and global variables.

Enumeration types begin with E
Example: EColorLevel
E is “Enumeration”.

Locals and parameters begin with a lower case
Example: nbytes
Is coding convention.

Getters and setters begin with Get and Set
Examples: SetLast(), GetFirst()

General Variables

• gROOT is a global root variable.
  Example: gROOT::GetListOf(), or

gROOT -> GetListOfCanvases() -> FindObject("c1");

to find the canvas named c1.

• gFile is the pointer of this opened ROOT File.

• gStyle

• gSystem

• gDirectory is the pointer to this current directory.

• gPad

• gRandom

gRandom is a pointer to the current random number generator (TRandom interface). By default, it points to a TRandom3 object. You can replace the current random number generator by deleting gRandom and recreating with your own desired generator.

• gEnv

• gGeoManager