Var mutex,empty,full:semaphore:=1,n,0;
       buffer:array[0..n-1] of item;   in,out:integer:=0,0;
Begin
  parbegin
   Producer: begin
     repeat
       produce an item in nextp;
       wait(empty);
       wait(mutex);
       buffer(in):=nextp;
       in:=(in+1) mod n;
       signal(mutex);
       signal(full);
    until false;  end
   parend  
end

consumer: begin
    repeat
       wait(full);
       wait(mutex);
       nextc:=buffer(out);
       out:=(out+1) mod n;
       signal(mutex);
       signal(empty);
       consume the item;
    until false; end

问问
若进程中wait顺序颠倒会怎样？