1 files changed, 110 insertions, 0 deletions
diff --git a/ACE/examples/System_V_IPC/SV_Semaphores/Semaphores_2.cpp b/ACE/examples/System_V_IPC/SV_Semaphores/Semaphores_2.cpp
new file mode 100644
index 00000000000..ce3685a7f36
--- /dev/null
+++ b/ACE/examples/System_V_IPC/SV_Semaphores/Semaphores_2.cpp
@@ -0,0 +1,110 @@
+// $Id$
+
+// Illustrates the use of the ACE_SV_Semaphore_Complex class and the
+// ACE_Malloc class using the ACE_Shared_Memory_Pool (which uses
+// System V shared memory).  Note that it doesn't matter whether the
+// parent or the child creates the semaphore since Semaphore_Complex
+// will correctly serialize the intialization of the mutex and synch
+// objects.
+
+#include "ace/Malloc_T.h"
+#include "ace/Shared_Memory_Pool.h"
+#include "ace/SV_Semaphore_Complex.h"
+#include "ace/OS_NS_unistd.h"
+
+
+
+#if defined (ACE_HAS_SYSV_IPC) && !defined(ACE_LACKS_SYSV_SHMEM)
+
+// Shared memory allocator (note that this chews up the
+// ACE_DEFAULT_SEM_KEY).
+static ACE_Malloc<ACE_SHARED_MEMORY_POOL, ACE_SV_Semaphore_Simple> my_alloc;
+
+const int SEM_KEY_1 = ACE_DEFAULT_SEM_KEY + 1;
+const int SEM_KEY_2 = ACE_DEFAULT_SEM_KEY + 2;
+
+static int
+parent (char *shm)
+{
+  char *s = shm;
+
+  // Both semaphores are initially created with a count of 0, i.e.,
+  // they are "locked."
+  ACE_SV_Semaphore_Complex mutex (SEM_KEY_1, ACE_SV_Semaphore_Complex::ACE_CREATE, 0);
+  ACE_SV_Semaphore_Complex synch (SEM_KEY_2, ACE_SV_Semaphore_Complex::ACE_CREATE, 0);
+
+  // This is a critical section, which is protected by the mutex
+  // semaphore.
+  for (char c = 'a'; c <= 'z'; c++)
+    *s++ = c;
+
+  *s = '\0';
+
+  if (mutex.release () == -1)
+    ACE_ERROR ((LM_ERROR, "%p", "parent mutex.release"));
+  else if (synch.acquire () == -1)
+    ACE_ERROR ((LM_ERROR, "%p", "parent synch.acquire"));
+
+  if (my_alloc.remove () == -1)
+    ACE_ERROR ((LM_ERROR, "%p\n", "my_alloc.remove"));
+  if (mutex.remove () == -1)
+    ACE_ERROR ((LM_ERROR, "%p\n", "mutex.remove"));
+  if (synch.remove () == -1)
+    ACE_ERROR ((LM_ERROR, "%p\n", "synch.remove"));
+  return 0;
+}
+
+static int
+child (char *shm)
+{
+  // Both semaphores are initially created with a count of 0, i.e.,
+  // they are "locked."
+  ACE_SV_Semaphore_Complex mutex (SEM_KEY_1, ACE_SV_Semaphore_Complex::ACE_CREATE, 0);
+  ACE_SV_Semaphore_Complex synch (SEM_KEY_2, ACE_SV_Semaphore_Complex::ACE_CREATE, 0);
+
+  // Perform "busy waiting" here until we acquire the semaphore.  This
+  // isn't really a good design -- it's just to illustrate that you
+  // can do non-blocking acquire() calls with the ACE System V
+  // semaphore wrappers.
+  while (mutex.tryacquire () == -1)
+    if (errno == EAGAIN)
+      ACE_DEBUG ((LM_DEBUG, "spinning in child!\n"));
+    else
+      ACE_ERROR_RETURN ((LM_ERROR, "child mutex.tryacquire"), 1);
+
+  for (char *s = (char *) shm; *s != '\0'; s++)
+    ACE_DEBUG ((LM_DEBUG, "%c", *s));
+
+  ACE_DEBUG ((LM_DEBUG, "\n"));
+
+  if (synch.release () == -1)
+    ACE_ERROR_RETURN ((LM_ERROR, "child synch.release"), 1);
+  return 0;
+}
+
+int
+ACE_TMAIN (int, ACE_TCHAR *[])
+{
+  char *shm = (char *) my_alloc.malloc (27);
+
+  switch (ACE_OS::fork ())
+    {
+    case -1:
+      ACE_ERROR_RETURN ((LM_ERROR, "fork failed\n"), -1);
+      /* NOTREACHED */
+    case 0:
+      // Child.
+      return child (shm);
+    default:
+      return parent (shm);
+    }
+}
+#else
+int ACE_TMAIN (int, ACE_TCHAR *[])
+{
+  ACE_ERROR ((LM_ERROR,
+              "SYSV IPC, or SYSV SHMEM is not supported on this platform\n"));
+  return 0;
+}
+#endif /* ACE_HAS_SYSV_IPC */
+