[ python-Bugs-1229788 ] Bus error in extension with gcc 3.3

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Bugs item #1229788, was opened at 2005-06-29 11:43
Message generated for change (Comment added) made by tjreedy
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Category: Extension Modules
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Gary Robinson (garyrob)
Assigned to: Nobody/Anonymous (nobody)
Summary: Bus error in extension with gcc 3.3

Initial Comment:
This text contains a c module with 4 versions of the same 
extremely simple function. All they do is return a float double to 
python. 

On Windows I have received a report from someone who can built 
the module, imported it into Python, and ran it successfully. 

It has also been reported that there is no problem when the 
extension is compiled with gcc 4.0 on OS X.

However, on OS X, if the extension is compiled with gcc 3.3, the 4th 
of the 4 function results in a bus error:


>>> from check import *
 fun0()
411.0
>>> fun1()
534.30000000000007
>>> fun2()
411.0
>>> fun3()
Bus error


I originally reported this on the C++ sig's mail list. They suggested I 
try dev-python. Scott David Daniels on that list helped me refine 
some 
test cases and verified that they all worked on Windows. 

Along the way it was suggested that I post a bug report. So this is it.

The code follows:

#include "Python.h"
static double value = 411.0;

static PyObject *
fun0(PyObject *self, PyObject *args)
{
    if (!PyArg_ParseTuple(args, "", NULL)) return NULL;
    return Py_BuildValue("d", value);
}

static PyObject *
fun1(PyObject *self, PyObject *args)
{
    return Py_BuildValue("d", 1.3*value);
}

static PyObject *
fun2(PyObject *self, PyObject *args)
{
    return PyFloat_FromDouble(value);
}

static PyObject *
fun3(PyObject *self, PyObject *args)
{
    return Py_BuildValue("d", value);
}


static PyMethodDef TestMethods[] = {
    {"fun0", fun0, METH_VARARGS, "Read args and return value"},
    {"fun1", fun1, METH_VARARGS, "Return value multiplied inline 
by 
1.3"},
    {"fun2", fun2, METH_VARARGS, "Return value using 
PyFloat_FromDouble"},
    {"fun3", fun3, METH_VARARGS, "Return value using 
Py_BuildValue 
without reading args -- causes bus error on OS X Panther with 
XCode 1.5 
installed"},
    {NULL, NULL, 0, NULL}        /* Sentinel */
};

PyMODINIT_FUNC
initcheck(void)
{
    PyObject *module;

    module = Py_InitModule3("check", TestMethods,
		"extension module with three functions.");
    if (module) {
	PyModule_AddStringConstant(module, "__version__", "0.02");
    }
}


----------------------------------------------------------------------

>Comment By: Terry J. Reedy (tjreedy)
Date: 2005-06-30 16:05

Message:
Logged In: YES 
user_id=593130

Do you have any reason to think the bug is in Python rather than 
the older version of gcc?  Or OSX?  Or even your computer?

If not, please consider closing.

Does OSX give you a stack trace?  If so,what is executing when 
the crash occurs?  In fun3, Py_BuildValue, or somehow 
inbewteen?

----------------------------------------------------------------------

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