[Python-Dev] Re: PEP 324 (process module)

[Peter Astrand]

> Last time I tried it there were still a few windows issues (docs say
> these have been resolved), but I thought the API was well-designed.

The details: The module works great on Windows currently, but requires the
win32all extensions. The idea is to get rid of this dependency by writing
a glue module, pretty much as _winreg.

Work on such a _process module has been done on two fronts:

* A friendly Python-developer has gotten quite far, but was experiencing
some strange hangs. I haven't been able to look at this work yet.

* I've started working on an implementation myself. I was using _winreg as
some sort of template. The problem is: I've never written extension
modules before :-) It was quite easy to export the numeric constants, but
when I came to creating Python objects, I was lost. I'll guess I need to
read some documentation.

This is what remains:

win32api:
 GetStdHandle
 GetCurrentProcess, DuplicateHandle

win32pipe:
 CreatePipe

win32process:
 CreateProcess, STARTUPINFO, GetExitCodeProcess

win32event:
 WaitForSingleObject


Here's the module so far:


/*
  _process.c
*/

#include "windows.h"
#include "Python.h"
#include "structmember.h"
#include "malloc.h" /* for alloca */

/* The win32api module reports the function name that failed,
   but this concept is not in the Python core.
   Hopefully it will one day, and in the meantime I dont
   want to lose this info...
*/
#define PyErr_SetFromWindowsErrWithFunction(rc, fnname) \
	PyErr_SetFromWindowsErr(rc)

/* Forward declares */

/* Doc strings */
// FIXME
PyDoc_STRVAR(module_doc,
"This module provides...\n");


static struct PyMethodDef process_methods[] = {
	NULL,
};

static void
insint(PyObject * d, char * name, long value)
{
	PyObject *v = PyInt_FromLong(value);
	if (!v || PyDict_SetItemString(d, name, v))
		PyErr_Clear();
	Py_XDECREF(v);
}

#define ADD_INT(val) insint(d, #val, val)


PyMODINIT_FUNC init_process(void)
{
	PyObject *m, *d;
	m = Py_InitModule3("_process", process_methods, module_doc);
	d = PyModule_GetDict(m);
	Py_INCREF(PyExc_WindowsError);
	if (PyDict_SetItemString(d, "error",
				 PyExc_WindowsError) != 0)
		return;

	/* Add the relevant constants */
	ADD_INT(DUPLICATE_SAME_ACCESS);
	ADD_INT(STARTF_USESTDHANDLES);
	ADD_INT(STD_INPUT_HANDLE);
	ADD_INT(STD_OUTPUT_HANDLE);
        ADD_INT(STD_ERROR_HANDLE);
	ADD_INT(INFINITE);
	ADD_INT(WAIT_OBJECT_0);
}

(I will be away for a couple of days.)

/Peter Åstrand <astrand at lysator.liu.se>