Non-uniform initial condition for using Labels

I am importing my meshed geometry from GMSH to FreeFEM along with the labels. I want to implement the following I.C. using labels. I tried using implicit function approach but it doesn’t work.

U = {1.0 at inlet i.e. x==-3 and 0 otherwise.} (Required Initial condition)

func ic = (x==-3); // if at inlet then returns 1 otherwise 0.
Vh u = ic; 

Maybe you can enlarge it a bit in order to take into account fluctuations of the mesh position:
func ic = (abs(x+3)<1.e-3);

Thanks @fb77 ! I will try that !