From ef8d8a5fd297bbe707f5f8cd98e678e5899f1a74 Mon Sep 17 00:00:00 2001
From: Dhanya Thattil <dhanya.thattil@psi.ch>
Date: Wed, 9 Jul 2025 17:19:54 +0200
Subject: [PATCH] raising a SIGINT when the child thread has an exception so
 that the parent thread can exit all the threads and clean up gracefully

---
 .../src/FrameSynchronizerApp.cpp              | 64 +++++++++++--------
 slsReceiverSoftware/src/Receiver.cpp          |  3 +
 2 files changed, 41 insertions(+), 26 deletions(-)

diff --git a/slsReceiverSoftware/src/FrameSynchronizerApp.cpp b/slsReceiverSoftware/src/FrameSynchronizerApp.cpp
index 1fa2f3fb1..69d85534a 100644
--- a/slsReceiverSoftware/src/FrameSynchronizerApp.cpp
+++ b/slsReceiverSoftware/src/FrameSynchronizerApp.cpp
@@ -541,45 +541,44 @@ int main(int argc, char *argv[]) {
     void *user_data = static_cast<void *>(&stat);
     std::thread combinerThread(Correlate, &stat);
 
+    std::exception_ptr threadException = nullptr;
     for (int i = 0; i != f.numReceivers; ++i) {
         uint16_t port = f.port + i;
         sem_t *semaphore = &semaphores[i];
-        threads.emplace_back([i, semaphore, port, user_data]() {
-            LOG(sls::logINFOBLUE)
-                << "Thread " << i << " [ Tid: " << gettid() << ']';
-            try {
-                sls::Receiver receiver(port);
-                receiver.registerCallBackStartAcquisition(
-                    StartAcquisitionCallback, user_data);
-                receiver.registerCallBackAcquisitionFinished(
-                    AcquisitionFinishedCallback, user_data);
-                receiver.registerCallBackRawDataReady(GetDataCallback,
-                                                      user_data);
+        threads.emplace_back(
+            [i, semaphore, port, user_data, &threadException]() {
+                LOG(sls::logINFOBLUE)
+                    << "Thread " << i << " [ Tid: " << gettid() << ']';
+                try {
+                    sls::Receiver receiver(port);
+                    receiver.registerCallBackStartAcquisition(
+                        StartAcquisitionCallback, user_data);
+                    receiver.registerCallBackAcquisitionFinished(
+                        AcquisitionFinishedCallback, user_data);
+                    receiver.registerCallBackRawDataReady(GetDataCallback,
+                                                          user_data);
 
-                /**	- as long as no Ctrl+C */
-                // each child shares the common semaphore
-                sem_wait(semaphore);
-            } catch (...) {
+                    /**	- as long as no Ctrl+C */
+                    // each child shares the common semaphore
+                    sem_wait(semaphore);
+                } catch (...) {
+                    // capture exception and raise SIGINT to exit gracefully
+                    threadException = std::current_exception();
+                    raise(SIGINT);
+                }
                 LOG(sls::logINFOBLUE)
                     << "Exiting Thread " << i << " [ Tid: " << gettid() << " ]";
-                for (auto &s : semaphores)
-                    sem_destroy(&s);
-                cleanup();
-                if (global_frame_status)
-                    sem_destroy(&(global_frame_status->available));
-                std::exit(EXIT_FAILURE);
-            }
-            LOG(sls::logINFOBLUE)
-                << "Exiting Thread " << i << " [ Tid: " << gettid() << " ]";
-            sem_destroy(semaphore);
-        });
+            });
     }
 
     for (auto &t : threads) {
         t.join();
     }
 
+    for (auto &s : semaphores)
+        sem_destroy(&s);
     cleanup();
+
     {
         std::lock_guard<std::mutex> lock(stat.mtx);
         stat.terminate = true;
@@ -588,6 +587,19 @@ int main(int argc, char *argv[]) {
     combinerThread.join();
     sem_destroy(&stat.available);
 
+    if (threadException) {
+        try {
+            std::rethrow_exception(threadException);
+        } catch (const std::exception &e) {
+            LOG(sls::logERROR)
+                << "Unhandled exception from thread: " << e.what();
+            return EXIT_FAILURE;
+        } catch (...) {
+            LOG(sls::logERROR) << "Unknown exception occurred in thread";
+            return EXIT_FAILURE;
+        }
+    }
+
     LOG(sls::logINFOBLUE) << "Goodbye!";
     return EXIT_SUCCESS;
 }
diff --git a/slsReceiverSoftware/src/Receiver.cpp b/slsReceiverSoftware/src/Receiver.cpp
index d81ecb33a..84bcd485d 100644
--- a/slsReceiverSoftware/src/Receiver.cpp
+++ b/slsReceiverSoftware/src/Receiver.cpp
@@ -29,6 +29,9 @@ Receiver::~Receiver() = default;
 
 Receiver::Receiver(uint16_t port) {
     validatePortNumber(port);
+    if (port == 9999) {
+        throw sls::RuntimeError("Throwing for testing purposes. ");
+    }
     tcpipInterface = make_unique<ClientInterface>(port);
 }