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v0.5.1
https://github.com/python/cpython
Revision a40c793d06ee2b42a5013015352616b4ca6b288b authored by Tim Peters on 05 September 2001, 22:36:56 UTC, committed by Tim Peters on 05 September 2001, 22:36:56 UTC
requires that errno ever get set, and it looks like glibc is already
playing that game.  New rules:

+ Never use HUGE_VAL.  Use the new Py_HUGE_VAL instead.

+ Never believe errno.  If overflow is the only thing you're interested in,
  use the new Py_OVERFLOWED(x) macro.  If you're interested in any libm
  errors, use the new Py_SET_ERANGE_IF_OVERFLOW(x) macro, which attempts
  to set errno the way C89 said it worked.

Unfortunately, none of these are reliable, but they work on Windows and I
*expect* under glibc too.
1 parent 75ed167
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Tip revision: a40c793d06ee2b42a5013015352616b4ca6b288b authored by Tim Peters on 05 September 2001, 22:36:56 UTC
Rework the way we try to check for libm overflow, given that C99 no longer
Tip revision: a40c793
xxobject.c

/* Use this file as a template to start implementing a new object type.
   If your objects will be called foobar, start by copying this file to
   foobarobject.c, changing all occurrences of xx to foobar and all
   occurrences of Xx by Foobar.  You will probably want to delete all
   references to 'x_attr' and add your own types of attributes
   instead.  Maybe you want to name your local variables other than
   'xp'.  If your object type is needed in other files, you'll have to
   create a file "foobarobject.h"; see intobject.h for an example. */


/* Xx objects */

#include "Python.h"

typedef struct {
	PyObject_HEAD
	PyObject	*x_attr;	/* Attributes dictionary */
} xxobject;

staticforward PyTypeObject Xxtype;

#define is_xxobject(v)		((v)->ob_type == &Xxtype)

static xxobject *
newxxobject(PyObject *arg)
{
	xxobject *xp;
	xp = PyObject_NEW(xxobject, &Xxtype);
	if (xp == NULL)
		return NULL;
	xp->x_attr = NULL;
	return xp;
}

/* Xx methods */

static void
xx_dealloc(xxobject *xp)
{
	Py_XDECREF(xp->x_attr);
	PyObject_DEL(xp);
}

static PyObject *
xx_demo(xxobject *self, PyObject *args)
{
	if (!PyArg_ParseTuple(args, ":demo"))
		return NULL;
	Py_INCREF(Py_None);
	return Py_None;
}

static PyMethodDef xx_methods[] = {
	{"demo",	(PyCFunction)xx_demo,	METH_VARARGS},
	{NULL,		NULL}		/* sentinel */
};

static PyObject *
xx_getattr(xxobject *xp, char *name)
{
	if (xp->x_attr != NULL) {
		PyObject *v = PyDict_GetItemString(xp->x_attr, name);
		if (v != NULL) {
			Py_INCREF(v);
			return v;
		}
	}
	return Py_FindMethod(xx_methods, (PyObject *)xp, name);
}

static int
xx_setattr(xxobject *xp, char *name, PyObject *v)
{
	if (xp->x_attr == NULL) {
		xp->x_attr = PyDict_New();
		if (xp->x_attr == NULL)
			return -1;
	}
	if (v == NULL) {
		int rv = PyDict_DelItemString(xp->x_attr, name);
		if (rv < 0)
			PyErr_SetString(PyExc_AttributeError,
                                        "delete non-existing xx attribute");
		return rv;
	}
	else
		return PyDict_SetItemString(xp->x_attr, name, v);
}

static PyTypeObject Xxtype = {
	PyObject_HEAD_INIT(&PyType_Type)
	0,			/*ob_size*/
	"xx",			/*tp_name*/
	sizeof(xxobject),	/*tp_basicsize*/
	0,			/*tp_itemsize*/
	/* methods */
	(destructor)xx_dealloc, /*tp_dealloc*/
	0,			/*tp_print*/
	(getattrfunc)xx_getattr, /*tp_getattr*/
	(setattrfunc)xx_setattr, /*tp_setattr*/
	0,			/*tp_compare*/
	0,			/*tp_repr*/
	0,			/*tp_as_number*/
	0,			/*tp_as_sequence*/
	0,			/*tp_as_mapping*/
	0,			/*tp_hash*/
};
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