[capi-sig] Re: Can't create new interpreter in multi thread

Aha, I reproduce your issue: https://bugs.python.org/issue43793

Currently, I understand that you must first acquire the GIL using PyGILState_Ensure()/PyGILState_Release() in the newly created thread to be able to call Py_NewInterpreter(). See: https://docs.python.org/dev/c-api/init.html#non-python-created-threads

Maybe tomorrow it will be possible to call Py_NewInterpreter() on a newly created thread which has no thread state.

Victor

On Fri, Apr 9, 2021 at 2:26 PM Kun He <hekun19890913@gmail.com> wrote:

Hi Victor,

Thanks for your response. I'm sorry that the attachment is not available. Anyway, I copy the C program as you can see below:

#include <stdio.h> #include <string.h>

#include <pthread.h>

#define PY_SSIZE_T_CLEAN #include <Python.h>

static PyObject* print_str(PyObject* self, PyObject* args) { char* content;

 if (!PyArg_ParseTuple(args, "s", &content))
     return NULL;

 printf("we want to print %s\n", content);

 Py_INCREF(Py_None);
 return Py_None;

}

static PyMethodDef NewinterMethods[] = { {"print_str", print_str, METH_VARARGS, "print the input string"}, {NULL, NULL, 0, NULL} };

static struct PyModuleDef newintermodule = { PyModuleDef_HEAD_INIT, "newinter", NULL, -1, NewinterMethods };

pthread_t tid;

void *thr_func(void *arg) { Py_NewInterpreter(); return ((void *)0); }

PyMODINIT_FUNC PyInit_newinter(void) { PyObject *m;

 m = PyModule_Create(&newintermodule);

#if PY_MAJOR_VERSION < 3 || (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 9) PyEval_InitThreads(); #endif

 int err = pthread_create(&tid, NULL, thr_func, NULL);
 if(err != 0)
 {
     printf("can't create thread\n");
     return NULL;
 }
 else
     printf("create new thread\n");

 return m;

}

And for test, a very simple Python script is used as below: import newinter newinter.print_str("test")

Sincerely, Kun

Victor Stinner <vstinner@python.org> 于2021年4月9日周五 下午2:01写道：

...

Hi Kun,

Can you please try to provide a short C program reproducing your issue? Sadly, I cannot see your attachement. Try to copy it directly in the email body.

Victor

On Fri, Apr 9, 2021 at 12:09 PM Kun He <hekun19890913@gmail.com> wrote:

...

Hello,

I'm working on a C extension interface of Python. I want to create a new interpreter by using the function Py_NewInterpreter() in a new thread, which is created by pthread_create (my test files are in attachment), but there are always errors when calling Py_NewInterpreter() such as "failed: object already tracked by the garbage collector".

I would like to ask how to solve the problem and create a new interpreter in multi thread in Python C extension?

Sincerely, Kun

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-- Night gathers, and now my watch begins. It shall not end until my death.

-- Night gathers, and now my watch begins. It shall not end until my death.