SWIG崩溃了Python

时间:2012-08-29 13:17:12

标签: python swig

我在这里有一个最简单的测试用例:

%module test
%{

static char* MyExceptionName = "_test.MyException";
static PyObject* MyException = NULL;

%}

%inline %{

static PyObject* Foo()
{
    PyErr_SetNone(MyException);
    return NULL;
}

%}

%init
{
    MyException = PyErr_NewException(MyExceptionName, NULL, NULL);
}

这是setup.py脚本:

from distutils.core import setup, Extension
setup(name="test", version="1.0",
    ext_modules = [Extension("_test", ["test_wrap.c"])])

当我构建它并按如下方式测试时,我得到:

 swig -python -threads test.i
 python_d -c "import test; test.Foo()"
 Fatal Python error: PyThreadState_Get: no current thread

我得到的追溯是

python27_d.dll!Py_FatalError(const char * msg=0x000000001e355a00)  Line 1677    C
python27_d.dll!PyThreadState_Get()  Line 330    C
python27_d.dll!PyErr_Restore(_object * type=0x00000000020d50b8, _object * value=0x0000000000000000, _object * traceback=0x0000000000000000)  Line 27 + 0x5 bytes    C
python27_d.dll!PyErr_SetObject(_object * exception=0x00000000020d50b8, _object * value=0x0000000000000000)  Line 58 C
python27_d.dll!PyErr_SetNone(_object * exception=0x00000000020d50b8)  Line 64   C
_test_d.pyd!Foo()  Line 2976    C

环境:

  • Win 7 64 bit,
  • win32上的Python 2.7.3(默认,2012年8月15日,18:18:52)[MSC v.1500 64位(AMD64)]
  • Swig 2.0.7

1 个答案:

答案 0 :(得分:3)

原因是错误的原因是因为通过

启用了-threads
swig -threads -python test.i

我们得到类似的东西(多余的代码已被编辑):

PyObject *_wrap_Foo(PyObject *SWIGUNUSEDPARM(self), PyObject *args) {
  PyObject *resultobj = 0;
  PyObject *result = 0 ;

  if (!PyArg_ParseTuple(args,(char *)":Foo")) SWIG_fail;
  {
    SWIG_PYTHON_THREAD_BEGIN_ALLOW;
    result = (PyObject *)Foo();
    SWIG_PYTHON_THREAD_END_ALLOW;
  }
  resultobj = result;
  return resultobj;
fail:
  return NULL;
}

static PyObject* Foo()
{
    PyErr_SetNone(MyException);
    return NULL;
}

请注意,当调用Foo()时,全局解释器锁已经被释放。 Foo()不应再进行任何Python API调用。

解决方案是使用SWIG_Python_SetErrorObj,它在调用Python C API之前抓取全局解释器锁。

static PyObject* Foo()
{
    SWIG_Python_SetErrorObj(MyException, Py_None);
    return NULL;
}

另一种方法是使用SWIG_PYTHON_THREAD_BEGIN_BLOCK;和SWIG_PYTHON_THREAD_END_BLOCK;

static PyObject* Foo()
{
    SWIG_PYTHON_THREAD_BEGIN_BLOCK; 

    PyErr_SetNone(MyException);

    SWIG_PYTHON_THREAD_END_BLOCK;
    return NULL;
}