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 *.
diff --git a/Objects/structseq.c b/Objects/structseq.c
index 603477f..ac3cf03 100644
--- a/Objects/structseq.c
+++ b/Objects/structseq.c
@@ -97,7 +97,7 @@
PyObject *ob;
PyStructSequence *res = NULL;
int len, min_len, max_len, i, n_unnamed_fields;
- static char *kwlist[] = {"sequence", "dict", 0};
+ static const char *kwlist[] = {"sequence", "dict", 0};
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|O:structseq",
kwlist, &arg, &dict))