regression - Stata: selecting the reference variables in an interaction -

when run following regression,

reg subject inschool#treatment#male 

i comparisons in reference inschool=0, treatment=0, , male=0, able change reference variables.

for example have comparisons done in reference inschool=1,treatment=0, , male=1.

i have used following characteristic command doesn't seem have effect.

char inschool[omit] 1 male[omit] 1 

am having syntax issue or there no way choose variable omit using #

thanks in advance!

from help fvvarlist:

you can specify base level of factor variable using ib. operator.