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 *.

1 files changed, 1 insertions, 1 deletions

diff --git a/Objects/weakrefobject.c b/Objects/weakrefobject.c
index 5412dd3..1de9434 100644
--- a/Objects/weakrefobject.c
+++ b/Objects/weakrefobject.c
@@ -126,7 +126,7 @@ gc_clear(PyWeakReference *self)
 static PyObject *
 weakref_call(PyWeakReference *self, PyObject *args, PyObject *kw)
 {
-    static char *argnames[] = {NULL};
+    static const char *argnames[] = {NULL};
 
     if (PyArg_ParseTupleAndKeywords(args, kw, ":__call__", argnames)) {
         PyObject *object = PyWeakref_GET_OBJECT(self);