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/Modules/_csv.c b/Modules/_csv.c
index da5ae0d..51dc89d 100644
--- a/Modules/_csv.c
+++ b/Modules/_csv.c
@@ -291,7 +291,7 @@
self->ob_type->tp_free((PyObject *)self);
}
-static char *dialect_kws[] = {
+static const char *dialect_kws[] = {
"dialect",
"delimiter",
"doublequote",