# HG changeset patch
# User Thomas Perl <m@thp.io>
# Date 1496516882 -7200
#      Sat Jun 03 21:08:02 2017 +0200
# Node ID 160e27767a070655d4e97b73a59a33c1fc24e3d7
# Parent  4243df51fe43e47419713d3d490ace342097514a
Py_SetFatalErrorAbortFunc: Allow embedding program to handle fatal errors

This allows graphical programs that dynamically load libpython to handle
fatal Python errors gracefully by showing a message dialog before exiting.

diff -r 4243df51fe43 -r 160e27767a07 Doc/c-api/sys.rst
--- a/Doc/c-api/sys.rst	Fri Feb 10 14:19:36 2017 +0100
+++ b/Doc/c-api/sys.rst	Sat Jun 03 21:08:02 2017 +0200
@@ -217,7 +217,19 @@
    make it dangerous to continue using the Python interpreter; e.g., when the
    object administration appears to be corrupted.  On Unix, the standard C library
    function :c:func:`abort` is called which will attempt to produce a :file:`core`
-   file.
+   file. If an abort function is set with :c:func:`Py_SetFatalErrorAbortFunc`,
+   it is called with *message* as argument and :c:func:`abort` is not called.
+
+
+.. c:function:: void Py_SetFatalErrorAbortFunc(PyFatalErrorAbortFunc func)
+
+   Set a program-defined function to be called instead of :c:func:`abort` when
+   :c:func:`Py_FatalError` is called. The embedding program should only use this
+   as a way of showing a (possibly graphical) error message to the user; the
+   Python interpreter should not be used, so the process should ideally abort
+   after notifying the user of the fatal error.
+
+   .. versionadded:: 3.x
 
 
 .. c:function:: void Py_Exit(int status)
diff -r 4243df51fe43 -r 160e27767a07 Include/pyerrors.h
--- a/Include/pyerrors.h	Fri Feb 10 14:19:36 2017 +0100
+++ b/Include/pyerrors.h	Sat Jun 03 21:08:02 2017 +0200
@@ -103,6 +103,8 @@
 
 /* Defined in Python/pylifecycle.c */
 PyAPI_FUNC(void) Py_FatalError(const char *message) _Py_NO_RETURN;
+typedef void (*PyFatalErrorAbortFunc)(const char *message);
+PyAPI_FUNC(void) Py_SetFatalErrorAbortFunc(PyFatalErrorAbortFunc func);
 
 #if defined(Py_DEBUG) || defined(Py_LIMITED_API)
 #define _PyErr_OCCURRED() PyErr_Occurred()
diff -r 4243df51fe43 -r 160e27767a07 Python/pylifecycle.c
--- a/Python/pylifecycle.c	Fri Feb 10 14:19:36 2017 +0100
+++ b/Python/pylifecycle.c	Sat Jun 03 21:08:02 2017 +0200
@@ -1399,6 +1399,15 @@
 
 /* Print fatal error message and abort */
 
+static PyFatalErrorAbortFunc *
+_fatal_error_abort_func = NULL;
+
+void
+Py_SetFatalErrorAbortFunc(PyFatalErrorAbortFunc func)
+{
+    _fatal_error_abort_func = func;
+}
+
 void
 Py_FatalError(const char *msg)
 {
@@ -1455,6 +1464,12 @@
     DebugBreak();
 #endif
     abort();
+
+    if (_fatal_error_abort_func != NULL) {
+        _fatal_error_abort_func(msg);
+    } else {
+        abort();
+    }
 }
 
 /* Clean up and exit */