54 lines
2.1 KiB
Diff
54 lines
2.1 KiB
Diff
|
From 625a405b8e42f944fdc1a87e36725f03b8817a85 Mon Sep 17 00:00:00 2001
|
||
|
|
From: William S Fulton <wsf@fultondesigns.co.uk>
|
||
|
|
Date: Sat, 5 Dec 2015 19:23:14 +0000
|
||
|
|
Subject: [PATCH] Add python inplace operator caveats to pyopers.swg
|
||
|
|
|
||
|
|
Observations reported in issue #562
|
||
|
|
---
|
||
|
|
Lib/python/pyopers.swg | 16 +++++++++++-----
|
||
|
|
1 file changed, 11 insertions(+), 5 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/Lib/python/pyopers.swg b/Lib/python/pyopers.swg
|
||
|
|
index ecbe783..80a0d68 100644
|
||
|
|
--- a/Lib/python/pyopers.swg
|
||
|
|
+++ b/Lib/python/pyopers.swg
|
||
|
|
@@ -151,11 +151,11 @@ __bool__ = __nonzero__
|
||
|
|
|
||
|
|
They translate the inplace C++ operators (+=, -=, ...) into the
|
||
|
|
corresponding python equivalents(__iadd__,__isub__), etc,
|
||
|
|
- disabling the ownership of the input 'self' pointer, and assigning
|
||
|
|
+ disabling the ownership of the input 'this' pointer, and assigning
|
||
|
|
it to the returning object:
|
||
|
|
|
||
|
|
- %feature("del") *::Operator;
|
||
|
|
- %feature("new") *::Operator;
|
||
|
|
+ %feature("del") *::Operator; // disables ownership by generating SWIG_POINTER_DISOWN
|
||
|
|
+ %feature("new") *::Operator; // claims ownership by generating SWIG_POINTER_OWN
|
||
|
|
|
||
|
|
This makes the most common case safe, ie:
|
||
|
|
|
||
|
|
@@ -174,8 +174,8 @@ __bool__ = __nonzero__
|
||
|
|
that never get deleted (maybe, not sure, it depends). But if that is
|
||
|
|
the case, you could recover the old behaviour using
|
||
|
|
|
||
|
|
- %feature("del","") A::operator+=;
|
||
|
|
- %feature("new","") A::operator+=;
|
||
|
|
+ %feature("del","0") A::operator+=;
|
||
|
|
+ %feature("new","0") A::operator+=;
|
||
|
|
|
||
|
|
which recovers the old behaviour for the class 'A', or if you are
|
||
|
|
100% sure your entire system works fine in the old way, use:
|
||
|
|
@@ -183,6 +183,12 @@ __bool__ = __nonzero__
|
||
|
|
%feature("del","") *::operator+=;
|
||
|
|
%feature("new","") *::operator+=;
|
||
|
|
|
||
|
|
+ The default behaviour assumes that the 'this' pointer's memory is
|
||
|
|
+ already owned by the SWIG object; it relinquishes ownership then
|
||
|
|
+ takes it back. This may not be the case though as the SWIG object
|
||
|
|
+ might be owned by memory managed elsewhere, eg after calling a
|
||
|
|
+ function that returns a C++ reference. In such case you will need
|
||
|
|
+ to use the features above to recover the old behaviour too.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#if defined(SWIGPYTHON_BUILTIN)
|