ctypes unwilling to allow pickling wide character

[jaraco]

BPO	5049
Nosy	@theller, @amauryfa, @jaraco

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields:

assignee = 'https://github.com/theller'
closed_at = <Date 2009-04-24.20:18:37.478>
created_at = <Date 2009-01-25.02:52:25.483>
labels = ['ctypes', 'type-bug']
title = 'ctypes unwilling to allow pickling wide character'
updated_at = <Date 2009-04-24.20:18:37.373>
user = 'https://github.com/jaraco'

bugs.python.org fields:

activity = <Date 2009-04-24.20:18:37.373>
actor = 'theller'
assignee = 'theller'
closed = True
closed_date = <Date 2009-04-24.20:18:37.478>
closer = 'theller'
components = ['ctypes']
creation = <Date 2009-01-25.02:52:25.483>
creator = 'jaraco'
dependencies = []
files = []
hgrepos = []
issue_num = 5049
keywords = ['patch']
message_count = 4.0
messages = ['80493', '80494', '82289', '86428']
nosy_count = 4.0
nosy_names = ['theller', 'amaury.forgeotdarc', 'jaraco', 'jnoller']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue5049'
versions = ['Python 2.6', 'Python 3.0', 'Python 3.1', 'Python 2.7']

[jaraco]

Using Python 2.6.1, I'm unable to pickle a simple object with an array
of wide characters.

import ctypes, pickle

class MyStruct(ctypes.Structure):
  _fields_ = [('name', ctypes.c_wchar*2)]

s = MyStruct('DC')

pickle.dumps(s) # raises ValueError.

Replace ctypes.c_wchar with ctypes.c_char and the pickling works fine.

[jaraco]

I just discovered that trying to pickle a structure with even just a
c_wchar (not an array) also fails.

[amauryfa]

the "case 'u':" in Module/_ctypes/_ctypes.c (function SimpleType_new)
seems misplaced: u is a scalar type, not a pointer.
Maybe a 's' was intended instead?

Index: Modules/_ctypes/_ctypes.c
===================================================================

--- Modules/_ctypes/_ctypes.c   (revision 68667)
+++ Modules/_ctypes/_ctypes.c   (working copy)
@@ -1951,7 +1951,7 @@
                        ml = &c_void_p_method;
                        stgdict->flags |= TYPEFLAG_ISPOINTER;
                        break;
-               case 'u':
+               case 's':
                case 'X':
                case 'O':
                        ml = NULL;

[theller]

Thanks, amaury, for the patch.

Fixed in trunk, release26-maint, release30-maint, py3k branch.
SVN revisions 71847, 71848, 71849, 71851.