From de02fd0b898e41fa91087300d82573d83e357b34 Mon Sep 17 00:00:00 2001
From: cooldome <cdome@bk.ru>
Date: Thu, 11 Apr 2019 12:51:51 +0100
Subject: [PATCH] fixes #10765 (#10993) [backport]

---
 lib/system/excpt.nim             | 25 +++++++++++++++++++++----
 tests/cpp/tterminate_handler.nim |  9 +++++++++
 2 files changed, 30 insertions(+), 4 deletions(-)
 create mode 100644 tests/cpp/tterminate_handler.nim

diff --git a/lib/system/excpt.nim b/lib/system/excpt.nim
index ec9d36c554..b421d96504 100644
--- a/lib/system/excpt.nim
+++ b/lib/system/excpt.nim
@@ -468,19 +468,36 @@ when defined(endb):
 when defined(cpp) and appType != "lib" and
     not defined(js) and not defined(nimscript) and
     hostOS != "standalone" and not defined(noCppExceptions):
+      
+  type 
+    StdException {.importcpp: "std::exception", header: "<exception>".} = object
+      
+  proc what(ex: StdException): cstring {.importcpp: "((char *)#.what())".}
+
   proc setTerminate(handler: proc() {.noconv.})
     {.importc: "std::set_terminate", header: "<exception>".}
+
   setTerminate proc() {.noconv.} =
     # Remove ourself as a handler, reinstalling the default handler.
     setTerminate(nil)
 
+    var msg = "Unknown error in unexpected exception handler"
+    try:
+      raise
+    except Exception:
+      msg = currException.getStackTrace() & "Error: unhandled exception: " &
+        currException.msg & " [" & $currException.name & "]"
+    except StdException as e:
+      msg = "Error: unhandled cpp exception: " & $e.what()
+    except:
+      msg = "Error: unhandled unknown cpp exception"
+      
     when defined(genode):
       # stderr not available by default, use the LOG session
-      echo currException.getStackTrace() & "Error: unhandled exception: " &
-              currException.msg & " [" & $currException.name & "]\n"
+      echo msg
     else:
-      writeToStdErr currException.getStackTrace() & "Error: unhandled exception: " &
-              currException.msg & " [" & $currException.name & "]\n"
+      writeToStdErr msg & "\n"
+
     quit 1
 
 when not defined(noSignalHandler) and not defined(useNimRtl):
diff --git a/tests/cpp/tterminate_handler.nim b/tests/cpp/tterminate_handler.nim
new file mode 100644
index 0000000000..79949f4dab
--- /dev/null
+++ b/tests/cpp/tterminate_handler.nim
@@ -0,0 +1,9 @@
+discard """
+  targets: "cpp"
+  outputsub: "Error: unhandled unknown cpp exception"
+  exitcode: 1
+"""
+type Crap {.importcpp: "int".} = object
+
+var c: Crap
+raise c
\ No newline at end of file