Aahz <aahz <at> pythoncraft.com> writes:
> Can you reproduce your problem with stub code that only creates threads?
> If yes, that indicates that you're messing with a thread structure
> somewhere. Note that because you're using gcc, it's possible there's a
> thread bug on Windows with your tool chain. You might want to check for
> bug reports.
Here's the simplest piece of code I could think of to reproduce the problem:
---------- primes.cpp ----------
#include <python.h>
#include <omp.h>
using namespace std;
int is_prime(const long n)
{
long i;
for (i = 2; i < n; i++)
if (n % i == 0) return 0;
return 1;
}
long nb_primes(const long n)
{
long i, nb = 0;
#pragma omp parallel for private(i) reduction(+ : nb) // It crashes
here.
for (i = 2; i <= n; i++)
if (is_prime(i)) nb += 1;
return nb;
}
static PyObject * nb_primes_wrapper(PyObject *self, PyObject *args)
{
long n, nb;
if (!PyArg_ParseTuple(args, "l", &n)) return NULL;
nb = nb_primes(n);
return Py_BuildValue("l", nb);
}
static PyMethodDef primes_methods[] =
{
{"nb_primes", nb_primes_wrapper, METH_VARARGS},
{NULL}
};
PyMODINIT_FUNC initprimes()
{
PyObject *module;
module = Py_InitModule("primes", primes_methods);
}
---------- end of primes.cpp ----------
I compile it using:
gcc -c -fopenmp -IC:/Python25/include primes.cpp
gcc -LC:/Python25/libs -LC:/mingw/lib -mdll -o primes.pyd primes.o -lpython25
-lgomp -lpthreadGC2
In Python:
import primes
primes.nb_primes(1000)
works fine, but
import primes
import threading
t = threading.Thread(target = primes.nb_primes, args = (1000,))
t.start()
crashes.
Would anybody be so kind and try to compile it with Microsoft or Intel compiler
and tell me if it also crashes (I tried Visual C++ 2005 Express Edition, but it
does not implement OpenMP). If the bug is with gcc, I will submit the problem to
the appropriate people.
Thank you,
Stéphane Larouche
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