Semaphores need to have a unique name -- fixes #7341

On Windows (and OSX) semaphores are named. If the name matches an existing
semaphore, it is re-used and not re-initialized. In case of multiple
LV2-plugins each with a worker-thread this can lead to a deadlock.

diff --git a/libs/ardour/worker.cc b/libs/ardour/worker.cc
index 0a5971fa3e22b934bcafbeae0bc79a789ed9406a..66f833d0871347e5d7144244448981f86ad43487 100644 (file)
--- a/libs/ardour/worker.cc
+++ b/libs/ardour/worker.cc
@@ -22,6 +22,7 @@
 
 #include "ardour/worker.h"
 #include "pbd/error.h"
+#include "pbd/compose.h"
 
 #include <glibmm/timer.h>
 
@@ -32,7 +33,7 @@ Worker::Worker(Workee* workee, uint32_t ring_size, bool threaded)
        , _requests(threaded ? new RingBuffer<uint8_t>(ring_size) : NULL)
        , _responses(new RingBuffer<uint8_t>(ring_size))
        , _response((uint8_t*)malloc(ring_size))
-       , _sem("worker_semaphore", 0)
+       , _sem(string_compose ("worker_semaphore%1", this).c_str(), 0)
        , _thread(NULL)
        , _exit(false)
        , _synchronous(!threaded)