resource no_race_semaphores()
   var N : int := 10; getarg(1, N)
   var sum: int := 0
   sem mutex := 1             # a semaphore
   write("race 2 processes, loop upper bound =", N)

   procedure fn(j, k: int) returns f: int
      f := j
      fa l := 1 to k -> f := f + l af
   end fn

   process Pr(j := 1 to 2)
      write("process", j)
      fa i := 1 to N ->
         P(mutex)             # pre-protocol: enter CRITICAL SECTION
         sum := fn(sum, i)
         V(mutex)             # post-protocol: exit CRITICAL SECTION
      af
      write("age()=", age(), "process", j, "end, sum = ", sum)
   end Pr

# correct race-free final value of sum is 2*220 = 440 for N of 10
# and 2*167167000 = 334334000 for N of 1000
end no_race_semaphores

/* ............... Example compile and run(s)

% sr -o no_race no_race.sr
% ./no_race
race 2 processes, loop upper bound = 10
process 1
age()= 38 process 1 end, sum =  220
process 2
age()= 44 process 2 end, sum =  440
% sr -c no_race.sr
% srl -L 1 -o no_race_L1 no_race_semaphores
% ./no_race_L1
race 2 processes, loop upper bound = 10
process 1
process 2
age()= 55 process 1 end, sum =  385
age()= 60 process 2 end, sum =  440
% ./no_race 1000
race 2 processes, loop upper bound = 1000
process 1
process 2
age()= 10370 process 1 end, sum =  273546420
age()= 11468 process 2 end, sum =  334334000
                                              */