From aa10d3b2758acbb3df11379a742ac9662feda971 Mon Sep 17 00:00:00 2001
From: Gerhard Hoffmann <g.hoffmann@atb-online.eu>
Date: Wed, 21 Feb 2024 10:39:03 +0100
Subject: [PATCH 1/2] Add atomic<bool> variable m_coinAttached to check for
 state change: send signal runProc_coinAttached only if state changes from
 false true.

---
 include/runProc.h | 5 +++++
 src/runProc.cpp   | 8 ++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/include/runProc.h b/include/runProc.h
index c2eb001..4179216 100755
--- a/include/runProc.h
+++ b/include/runProc.h
@@ -15,6 +15,7 @@
 #include <QDebug>
 #include "datIf.h"
 #include <QSharedMemory>
+#include <atomic>
 #include "sendWRcmd.h"
 #include "controlBus.h"
 #include "storeINdata.h"
@@ -35,6 +36,10 @@ class T_runProc : public QObject
 
     void restoreDeviceParameter(struct T_devices *deviceSettings);
 
+#ifndef THIS_IS_CA_MASTER
+    std::atomic_bool m_coinAttached{false};
+#endif
+
 private slots:
     void runProc_slotProcess(void);
     bool bl_performComplStart(void);
diff --git a/src/runProc.cpp b/src/runProc.cpp
index 1666de8..d7af5e8 100644
--- a/src/runProc.cpp
+++ b/src/runProc.cpp
@@ -48,8 +48,12 @@ T_runProc::T_runProc()
 void T_runProc::runProc_slotProcess(void)
 {
 #ifndef THIS_IS_CA_MASTER
-    if (epi_getDI_CoinAttach()) {
-        emit runProc_coinAttached();
+    bool const coinAttached = epi_getDI_CoinAttach();
+    if (m_coinAttached.exchange(coinAttached) == false) {
+        if (coinAttached) {
+            // old value was false, and new value is true
+            emit runProc_coinAttached();
+        }
     }
     cash_paymentProcessing();
     doors_supervise();

From 9cac6a6461d3da607f6495bbec46fe8537340e3b Mon Sep 17 00:00:00 2001
From: Gerhard Hoffmann <g.hoffmann@atb-online.eu>
Date: Wed, 21 Feb 2024 10:46:34 +0100
Subject: [PATCH 2/2] Added comment for std::atomic<bool>::exchange()

---
 src/runProc.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/runProc.cpp b/src/runProc.cpp
index d7af5e8..a7783d8 100644
--- a/src/runProc.cpp
+++ b/src/runProc.cpp
@@ -49,6 +49,9 @@ void T_runProc::runProc_slotProcess(void)
 {
 #ifndef THIS_IS_CA_MASTER
     bool const coinAttached = epi_getDI_CoinAttach();
+    // exchange: (atomically) replaces the underlying value of m_coinAttached
+    // with the value of coinAttached, returns the value of m_coinAttached
+    // before the call
     if (m_coinAttached.exchange(coinAttached) == false) {
         if (coinAttached) {
             // old value was false, and new value is true