DPL: better error message when DPL_ENABLE_STACKTRACE not set

Author: ktf

Framework/Core/src/runDataProcessing.cxx

@@ -812,9 +812,14 @@ int doChild(int argc, char** argv, ServiceRegistry& serviceRegistry, const o2::f
                << boost::current_exception_diagnostic_information(true);
     return 1;
   } catch (o2::framework::RuntimeErrorRef e) {
-    LOG(ERROR) << "Unhandled o2::framework::runtime_error reached the top of main, device shutting down. Details follow: \n";
     auto& err = o2::framework::error_from_ref(e);
-    backtrace_symbols_fd(err.backtrace, err.maxBacktrace, STDERR_FILENO);
+    if (err.maxBacktrace != 0) {
+      LOG(ERROR) << "Unhandled o2::framework::runtime_error reached the top of main, device shutting down. Details follow: \n";
+      backtrace_symbols_fd(err.backtrace, err.maxBacktrace, STDERR_FILENO);
+    } else {
+      LOG(ERROR) << "Unhandled o2::framework::runtime_error reached the top of main, device shutting down."
+                    " Recompile with DPL_ENABLE_BACKTRACE=1 to get more information.";
+    }
     return 1;
   } catch (std::exception& e) {
     LOG(ERROR) << "Unhandled std::exception reached the top of main: " << e.what() << ", device shutting down.";