package Semafor_Bin is
protected type Semafor_Bin (N: Natural) is
entry PB;
procedure VB;
private
count: natural :=N
end Semafor_Bin;
type Semafor_Bin_Acc is access all Semafor_Bin;
end Semafor_Bin;
package body Semafor_Bin is
protected body Semafor_Bin is
entry PB when count>0 is
begin count:=count-1;
end PB;
procedure VB is
begin count:=count+1;
end VB
end Semafor_Bin
begin
null;
end Semafor_Bin;