ecin · August 31, 2012 17:34 · Sep 2, 2012 · Sep 2, 2012 · Sep 2, 2012 · Sep 2, 2012
diff --git a/probes.go → goarena.go b/probes.go → goarena.go
diff --git a/spectator.d b/spectator.d
@@ -0,0 +1,9 @@
+golang*::Ping:
+{
+    printf("Ping hits, counter goes up to #%d!", arg0);
+}
+
+golang*::Pong:
+{
+    printf("Pong connects, counter goes down to #%d!", arg0);
+}
diff --git a/probes.c b/probes.c
@@ -7,16 +7,16 @@
 */
 #include "probes.h"
 
-void Ping() {
-  GOLANG_PING();
+void Ping(int n) {
+  GOLANG_PING(n);
 }
 
 int Ping_enabled() {
   return GOLANG_PING_ENABLED();
 }
 
-void Pong() {
-  GOLANG_PONG();
+void Pong(int n) {
+  GOLANG_PONG(n);
 }
 
 int Pong_enabled() {

diff --git a/probes.d b/probes.d
@@ -3,6 +3,6 @@
   dtrace -o probes.h -h -s probes.d
 */
 provider golang {
-  probe ping();
-  probe pong();
+  probe ping(int);
+  probe pong(int);
 };
diff --git a/probes.go b/probes.go
@@ -1,5 +1,10 @@
 package main
 
+/*
+Ping vs Pong: A Gladiatorial Match
+Two goroutines enter, only one leaves...
+*/
+
 /*
 #cgo LDFLAGS: -lprobes -L/usr/local/lib
 #include "probes.h"
@@ -13,6 +18,7 @@ import (
 
 func ping(c chan int, q chan int) {
   for ;; {
+    // Prepare a swing
     time.Sleep(time.Duration(rand.Intn(5)) * time.Second)
     n := <- c
     n += 1
@@ -22,12 +28,14 @@ func ping(c chan int, q chan int) {
     }
 
     c <- n
+    // Dtrace spectators: roar for Ping!
     C.Ping(C.int(n))
   }
 }
 
 func pong(c chan int, q chan int) {
   for ;; {
+    // Charge an attack
     time.Sleep(time.Duration(rand.Intn(5)) * time.Second)
     n := <- c
     n -= 1
@@ -37,6 +45,7 @@ func pong(c chan int, q chan int) {
     }
 
     c <- n
+    // Dtrace spectators: cheer for Pong!
     C.Pong(C.int(n))
   }
 }
@@ -45,17 +54,19 @@ func main() {
   c := make(chan int, 2)
   q := make(chan int)
 
+  // Ping and Pong enter the arena
   go ping(c, q)
   go pong(c, q)
 
+  // The match starts!
   c <- 5
 
-  // Wait for quit
+  // Wait for victor signal
   winner := <- q
 
   if winner == 0 {
-    println("Ping wins!")
+    println("After a long and arduous battle, Pong falls to its knees, its body a weary mess. Ping wins!")
   } else {
-    println("Pong wins!")
+    println("Overcome by one too many wounds, Ping rushes to the ground. Pong wins!")
   }
 }
diff --git a/probes.h b/probes.h
@@ -2,7 +2,7 @@
 /* ... */
 
 /* probes.c functions */
-void Ping();
+void Ping(int);
 int  Ping_enabled();
-void Pong();
+void Pong(int);
 int  Pong_enabled();
diff --git a/probes.go b/probes.go
@@ -0,0 +1,61 @@
+package main
+
+/*
+#cgo LDFLAGS: -lprobes -L/usr/local/lib
+#include "probes.h"
+*/
+import "C"
+
+import (
+  "time"
+  "math/rand"
+)
+
+func ping(c chan int, q chan int) {
+  for ;; {
+    time.Sleep(time.Duration(rand.Intn(5)) * time.Second)
+    n := <- c
+    n += 1
+
+    if n == 10 {
+      q <- 0
+    }
+
+    c <- n
+    C.Ping(C.int(n))
+  }
+}
+
+func pong(c chan int, q chan int) {
+  for ;; {
+    time.Sleep(time.Duration(rand.Intn(5)) * time.Second)
+    n := <- c
+    n -= 1
+
+    if n == 0 {
+      q <- 1
+    }
+
+    c <- n
+    C.Pong(C.int(n))
+  }
+}
+
+func main() {
+  c := make(chan int, 2)
+  q := make(chan int)
+
+  go ping(c, q)
+  go pong(c, q)
+
+  c <- 5
+
+  // Wait for quit
+  winner := <- q
+
+  if winner == 0 {
+    println("Ping wins!")
+  } else {
+    println("Pong wins!")
+  }
+}
diff --git a/probes.h b/probes.h
@@ -1,6 +1,7 @@
 /* Header file generated by dtrace */
 /* ... */
 
+/* probes.c functions */
 void Ping();
 int  Ping_enabled();
 void Pong();

diff --git a/probes.h b/probes.h
@@ -0,0 +1,7 @@
+/* Header file generated by dtrace */
+/* ... */
+
+void Ping();
+int  Ping_enabled();
+void Pong();
+int  Pong_enabled();
diff --git a/probes.c b/probes.c
@@ -1,17 +1,24 @@
+/*
+  Compile probes.c as a shared library
+  In Mac OS X (http://www.finkproject.org/doc/porting/shared.php#build-lib):
+  cc -fno-common -c probes.c
+  cc -dynamiclib -install_name /usr/local/lib/libprobes.dylib -o libprobes.dylib probes.o
+  cp libprobes.dylib /usr/local/lib/
+*/
 #include "probes.h"
 
 void Ping() {
   GOLANG_PING();
 }
 
-bool Ping_enabled() {
+int Ping_enabled() {
   return GOLANG_PING_ENABLED();
 }
 
 void Pong() {
   GOLANG_PONG();
 }
 
-bool Pong_enabled() {
+int Pong_enabled() {
   return GOLANG_PONG_ENABLED();
-}
+}
diff --git a/probes.c b/probes.c
@@ -0,0 +1,17 @@
+#include "probes.h"
+
+void Ping() {
+  GOLANG_PING();
+}
+
+bool Ping_enabled() {
+  return GOLANG_PING_ENABLED();
+}
+
+void Pong() {
+  GOLANG_PONG();
+}
+
+bool Pong_enabled() {
+  return GOLANG_PONG_ENABLED();
+}
diff --git a/probes.d b/probes.d
@@ -0,0 +1,8 @@
+/* 
+  Generate probes.h header file with:
+  dtrace -o probes.h -h -s probes.d
+*/
+provider golang {
+  probe ping();
+  probe pong();
+};