Fix thread safety issue

1 files changed, 11 insertions, 6 deletions

diff --git a/butl/diagnostics.cxx b/butl/diagnostics.cxx
index e4c22dc..ad84810 100644
--- a/butl/diagnostics.cxx
+++ b/butl/diagnostics.cxx
@@ -28,14 +28,19 @@ namespace butl
   diag_record::
   ~diag_record () noexcept (false)
   {
-    // Don't flush the record if this destructor was called as part of
-    // the stack unwinding. Right now this means we cannot use this
-    // mechanism in destructors, which is not a big deal, except for
-    // one place: exception_guard. So for now we are going to have
-    // this ugly special check which we will be able to get rid of
-    // once C++17 uncaught_exceptions() becomes available.
+    // Don't flush the record if this destructor was called as part of the
+    // stack unwinding.
+    //
+#ifdef BUTL_CXX17_UNCAUGHT_EXCEPTIONS
+    if (uncaught_ == std::uncaught_exceptions ())
+      flush ();
+#else
+    // Fallback implementation. Right now this means we cannot use this
+    // mechanism in destructors, which is not a big deal, except for one
+    // place: exception_guard. Thus the ugly special check.
     //
     if (!std::uncaught_exception () || exception_unwinding_dtor)
       flush ();
+#endif
   }
 }