A possible code bug about WIN32 macro

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1

In file Include/pythonrun.h, we have code

#if defined(WIN32) && !defined(MS_WIN64) && !defined(_M_ARM) && defined(_MSC_VER) && _MSC_VER >= 1300
/* Enable stack checking under Microsoft C */
// When changing the platforms, ensure PyOS_CheckStack() docs are still correct
#define USE_STACKCHECK
#endif

But I only see _WIN32 as a predefined macro in MSVC and I didn’t find “#define WIN32” in cpython (maybe I miss it?).

Maybe WIN32 should be _WIN32.

2

Likely relevant:

1 Like
3

But if we never define WIN32 macro, we will never have USE_STACKCHECK macro, then we can never use function PyOS_CheckStack().

See the doc.

4

For example, we have code in file object.c

int
PyObject_Print(PyObject *op, FILE *fp, int flags)
{
    int ret = 0;
    if (PyErr_CheckSignals())
        return -1;
#ifdef USE_STACKCHECK
    if (PyOS_CheckStack()) {
        PyErr_SetString(PyExc_MemoryError, "stack overflow");
        return -1;
    }
#endif
    clearerr(fp); /* Clear any previous error condition */
    if (op == NULL) {
        Py_BEGIN_ALLOW_THREADS
        fprintf(fp, "<nil>");
        Py_END_ALLOW_THREADS
    }
    else {
        if (Py_REFCNT(op) <= 0) {
            Py_BEGIN_ALLOW_THREADS
            fprintf(fp, "<refcnt %zd at %p>", Py_REFCNT(op), (void *)op);
            Py_END_ALLOW_THREADS
        }
        else {
            PyObject *s;
            if (flags & Py_PRINT_RAW)
                s = PyObject_Str(op);
            else
                s = PyObject_Repr(op);
            if (s == NULL) {
                ret = -1;
            }
            else {
                assert(PyUnicode_Check(s));
                const char *t;
                Py_ssize_t len;
                t = PyUnicode_AsUTF8AndSize(s, &len);
                if (t == NULL) {
                    ret = -1;
                }
                else {
                    fwrite(t, 1, len, fp);
                }
                Py_DECREF(s);
            }
        }
    }
    if (ret == 0) {
        if (ferror(fp)) {
            PyErr_SetFromErrno(PyExc_OSError);
            clearerr(fp);
            ret = -1;
        }
    }
    return ret;
}

Only if we have USE_STACKCHECK macro, we can use PyOS_CheckStack().

Because it is only a check, it will not affect cpython in most situations.