diff --git a/lib/py/src/ext/binary.cpp b/lib/py/src/ext/binary.cpp
index 85d8d92..423fa8f 100644
--- a/lib/py/src/ext/binary.cpp
+++ b/lib/py/src/ext/binary.cpp
@@ -17,6 +17,7 @@
  * under the License.
  */
 
+#define PY_SSIZE_T_CLEAN
 #include "ext/binary.h"
 namespace apache {
 namespace thrift {
diff --git a/lib/py/src/ext/compact.cpp b/lib/py/src/ext/compact.cpp
index 15a99a0..ae89f2a 100644
--- a/lib/py/src/ext/compact.cpp
+++ b/lib/py/src/ext/compact.cpp
@@ -17,6 +17,7 @@
  * under the License.
  */
 
+#define PY_SSIZE_T_CLEAN
 #include "ext/compact.h"
 
 namespace apache {