Add const to several API functions that take char *. In C++, it's an error to pass a string literal to a char* function without a const_cast(). Rather than require every C++ extension module to put a cast around string literals, fix the API to state the const-ness. I focused on parts of the API where people usually pass literals: PyArg_ParseTuple() and friends, Py_BuildValue(), PyMethodDef, the type slots, etc. Predictably, there were a large set of functions that needed to be fixed as a result of these changes. The most pervasive change was to make the keyword args list passed to PyArg_ParseTupleAndKewords() to be a const char *kwlist[]. One cast was required as a result of the changes: A type object mallocs the memory for its tp_doc slot and later frees it. PyTypeObject says that tp_doc is const char *; but if the type was created by type_new(), we know it is safe to cast to char *.

--- a/Objects/moduleobject.c	Sat Dec 10 17:44:27 2005 +0000
+++ b/Objects/moduleobject.c	Sat Dec 10 18:50:16 2005 +0000
@@ -15,7 +15,7 @@
 };
 
 PyObject *
-PyModule_New(char *name)
+PyModule_New(const char *name)
 {
 	PyModuleObject *m;
 	PyObject *nameobj;
@@ -149,10 +149,10 @@
 static int
 module_init(PyModuleObject *m, PyObject *args, PyObject *kwds)
 {
-	static char *kwlist[] = {"name", "doc", NULL};
+	static const char *kwlist[] = {"name", "doc", NULL};
 	PyObject *dict, *name = Py_None, *doc = Py_None;
-	if (!PyArg_ParseTupleAndKeywords(args, kwds, "S|O:module.__init__", kwlist,
-					 &name, &doc))
+	if (!PyArg_ParseTupleAndKeywords(args, kwds, "S|O:module.__init__",
+                                         kwlist, &name, &doc))
 		return -1;
 	dict = m->md_dict;
 	if (dict == NULL) {