RosettaCodeData/Task/Introspection/FreeBASIC/introspection-3.basic

#Undef Abs  '' undefine Abs keyword
Dim bloop As Integer = -15
#IfDef bloop
  #IfDef Abs
    Print "Abs(bloop) = "; Abs(bloop)
  #Else
    Print "Abs is not available"
  #EndIf
#Else
  Print "bloop does not exist"
#EndIf
Sleep