From f029a3d88fa6717d893c43a4bf186279a428cf29 Mon Sep 17 00:00:00 2001
From: Piotr Jarosik <piotr.jarosik@us4us.eu>
Date: Fri, 17 Dec 2021 09:19:47 +0100
Subject: [PATCH] Us4R buffer unregistration will be performed only once.

---
 arrus/core/devices/us4r/Us4RImpl.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arrus/core/devices/us4r/Us4RImpl.cpp b/arrus/core/devices/us4r/Us4RImpl.cpp
index 29b834c6d..a1ca547cb 100644
--- a/arrus/core/devices/us4r/Us4RImpl.cpp
+++ b/arrus/core/devices/us4r/Us4RImpl.cpp
@@ -155,7 +155,10 @@ void Us4RImpl::stopDevice() {
     if (this->buffer != nullptr) {
         this->buffer->shutdown();
         std::this_thread::sleep_for(std::chrono::milliseconds(1000));
-        getProbeImpl()->unregisterOutputBuffer(this->buffer.get(), this->us4rBuffer);
+        if(this->us4rBuffer) {
+            getProbeImpl()->unregisterOutputBuffer(this->buffer.get(), this->us4rBuffer);
+            this->us4rBuffer.reset();
+        }
     }
     this->state = State::STOPPED;
 }