produers-consumers updated

Author: coderxiang

Concurrency/.gitignore

@@ -1,4 +1,11 @@
-Some code snippet regarding concurrency in OCaml.
+Code snippet regarding concurrency (Mutex, Condition, Thread) in OCaml.
 
 - `pro_con.ml`: Producers-Consumers Problem
 - `concurrency.ml` and `bank.ml` are from [CS3110 of Cornell](http://www.cs.cornell.edu/courses/cs3110/2013sp/recitations/rec17.html)
+
+# Usage
+
+	ocamlmktop -thread unix.cma threads.cma -o mytop
+	./mytop -I +threads
+	# test ();;
+	

Concurrency/README.md

@@ -12,7 +12,7 @@ let produce () =
   Mutex.lock m2;
   while !cnt = buffer_size do Condition.wait not_full m2 done;
 
-  cnt := !cnt + 1;
+  incr cnt;
   print_string ("One more item is added to the buffer, now with size " ^
   (string_of_int !cnt) ^ "\n");
   flush stdout;
@@ -24,7 +24,7 @@ let consume () =
   Mutex.lock m2;
   while !cnt = 0 do Condition.wait not_empty m2 done;
 
-  cnt := !cnt - 1;
+  decr cnt;
   print_string ("One more item is removed to the buffer, now with size " ^
   (string_of_int !cnt) ^ "\n");
   flush stdout;