[New-bugs-announce] [issue7505] ctypes not converting None to Null in 64-bit system

[Venkateswaran]

New submission from Venkateswaran <wenkat.s at gmail.com>:

The attached code is failing to convert None to Null. It is successful 
if the int* is shifted towards the beginning of argument list. The bug 
is actually in 32/64 bit pointers as the code works on a 32 bit system.

The bug disappears if I reduce the number of arguments to less than 10.

I created the so using the command - "gcc  -shared -fPIC  -o libtest.so 
libtest.c", (gcc (Debian 4.3.2-1.1) 4.3.2) 

The c file is as follows:

libtest.c
#include <stdint.h>
#include <stdio.h>


int32_t where ( int32_t a, int32_t c, int32_t d, int32_t e, int32_t f, 
int32_t g, int32_t h, int32_t *b, int32_t i, int32_t j, int32_t k, 
int32_t l)
{
    printf("b = %p\n", (void *)b);
    printf("a = %d, c = %d, d = %d, e = %d, f = %d, g = %d, h = %d, i = 
%d, j = %d, k = %d,  l = %d", a,c,d,e,f,g,h,i,j,k,l);

    return 100;

} /* where() */

Python Code:
import ctypes

libtest = ctypes.CDLL('./libtest.so')
where = libtest.where
where.restype = ctypes.c_int
where.argtypes = [ 
                    ctypes.c_int32, ctypes.c_int32, ctypes.c_int32,          
ctypes.c_int32, ctypes.c_int32, ctypes.c_int32, ctypes.c_int32,
                    ctypes.POINTER(ctypes.c_int32),
                    ctypes.c_int32, ctypes.c_int32, ctypes.c_int32, 
ctypes.c_int32,
                 ]


a = 7
b = None

status = where(a,a,a,a,a,a,a,b,a,a,a,a)

----------
assignee: theller
components: ctypes
files: test.py
messages: 96385
nosy: theller, wenkat_s
severity: normal
status: open
title: ctypes not converting None to Null in 64-bit system
type: crash
versions: Python 2.5, Python 2.6
Added file: http://bugs.python.org/file15557/test.py

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue7505>
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