sharedmemory example: Handle QSharedMemory::AlreadyExists by attaching

Not all platforms clean up the shared memory entries on exit, so the
example needs to handle that case, by attaching instead, as documented.

Change-Id: Ifbcf92d0fad429caf30710bd8a344831cb0d859c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/examples/corelib/ipc/sharedmemory/dialog.cpp b/examples/corelib/ipc/sharedmemory/dialog.cpp
index ac171ef943..b656cc0c67 100644
--- a/examples/corelib/ipc/sharedmemory/dialog.cpp
+++ b/examples/corelib/ipc/sharedmemory/dialog.cpp
@@ -89,9 +89,13 @@ void Dialog::loadFromFile()
     int size = buffer.size();
 
     if (!sharedMemory.create(size)) {
-        ui.label->setText(tr("Unable to create shared memory segment: %1")
-                            .arg(sharedMemory.errorString()));
-        return;
+        if (sharedMemory.error() == QSharedMemory::AlreadyExists) {
+            sharedMemory.attach();
+        } else {
+            ui.label->setText(tr("Unable to create or attach to shared memory segment: %1")
+                                .arg(sharedMemory.errorString()));
+            return;
+        }
     }
     sharedMemory.lock();
     char *to = (char*)sharedMemory.data();