diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index 4b654a0..3d175c7 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -1414,7 +1414,7 @@
     {"closed", (getter)BufferedIOMixin_closed_get, NULL, NULL},
     {"name", (getter)BufferedIOMixin_name_get, NULL, NULL},
     {"mode", (getter)BufferedIOMixin_mode_get, NULL, NULL},
-    {0}
+    {NULL}
 };
 
 
@@ -1768,7 +1768,7 @@
     {"closed", (getter)BufferedIOMixin_closed_get, NULL, NULL},
     {"name", (getter)BufferedIOMixin_name_get, NULL, NULL},
     {"mode", (getter)BufferedIOMixin_mode_get, NULL, NULL},
-    {0}
+    {NULL}
 };
 
 
@@ -2021,7 +2021,7 @@
 
 static PyGetSetDef BufferedRWPair_getset[] = {
     {"closed", (getter)BufferedRWPair_closed_get, NULL, NULL},
-    {0}
+    {NULL}
 };
 
 PyTypeObject PyBufferedRWPair_Type = {
@@ -2157,7 +2157,7 @@
     {"closed", (getter)BufferedIOMixin_closed_get, NULL, NULL},
     {"name", (getter)BufferedIOMixin_name_get, NULL, NULL},
     {"mode", (getter)BufferedIOMixin_mode_get, NULL, NULL},
-    {0}
+    {NULL}
 };
 
 
diff --git a/Modules/_io/bytesio.c b/Modules/_io/bytesio.c
index 0068cb7..add61d5 100644
--- a/Modules/_io/bytesio.c
+++ b/Modules/_io/bytesio.c
@@ -684,7 +684,7 @@
 static PyGetSetDef bytesio_getsetlist[] = {
     {"closed",  (getter)bytesio_get_closed, NULL,
      "True if the file is closed."},
-    {0},            /* sentinel */
+    {NULL},            /* sentinel */
 };
 
 static struct PyMethodDef bytesio_methods[] = {
diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index c0f5c90..4499ee2 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -987,7 +987,7 @@
 	{"closefd", (getter)get_closefd, NULL, 
 		"True if the file descriptor will be closed"},
 	{"mode", (getter)get_mode, NULL, "String giving the file mode"},
-	{0},
+	{NULL},
 };
 
 PyTypeObject PyFileIO_Type = {
diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c
index ef6d516..5e018da 100644
--- a/Modules/_io/iobase.c
+++ b/Modules/_io/iobase.c
@@ -700,7 +700,7 @@
 
 static PyGetSetDef IOBase_getset[] = {
     {"closed", (getter)IOBase_closed_get, NULL, NULL},
-    {0}
+    {NULL}
 };
 
 
diff --git a/Modules/_io/stringio.c b/Modules/_io/stringio.c
index d75a604..136f41d 100644
--- a/Modules/_io/stringio.c
+++ b/Modules/_io/stringio.c
@@ -723,7 +723,7 @@
     {"encoding",       (getter)stringio_encoding,       NULL, NULL},
     {"errors",         (getter)stringio_errors,         NULL, NULL},
     {"line_buffering", (getter)stringio_line_buffering, NULL, NULL},
-    {0}
+    {NULL}
 };
 
 PyTypeObject PyStringIO_Type = {
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index cc229a8..26fc68d 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -102,7 +102,7 @@
 static PyGetSetDef TextIOBase_getset[] = {
     {"encoding", (getter)TextIOBase_encoding_get, NULL, TextIOBase_encoding_doc},
     {"newlines", (getter)TextIOBase_newlines_get, NULL, TextIOBase_newlines_doc},
-    {0}
+    {NULL}
 };
 
 PyTypeObject PyTextIOBase_Type = {
@@ -534,12 +534,12 @@
     {"getstate", (PyCFunction)IncrementalNewlineDecoder_getstate, METH_NOARGS},
     {"setstate", (PyCFunction)IncrementalNewlineDecoder_setstate, METH_O},
     {"reset", (PyCFunction)IncrementalNewlineDecoder_reset, METH_NOARGS},
-    {0}
+    {NULL}
 };
 
 static PyGetSetDef IncrementalNewlineDecoder_getset[] = {
     {"newlines", (getter)IncrementalNewlineDecoder_newlines_get, NULL, NULL},
-    {0}
+    {NULL}
 };
 
 PyTypeObject PyIncrementalNewlineDecoder_Type = {
@@ -2374,7 +2374,7 @@
     {"newlines", (getter)TextIOWrapper_newlines_get, NULL, NULL},
     {"_CHUNK_SIZE", (getter)TextIOWrapper_chunk_size_get,
                     (setter)TextIOWrapper_chunk_size_set, NULL},
-    {0}
+    {NULL}
 };
 
 PyTypeObject PyTextIOWrapper_Type = {