--- a/linux-gpib-user/language/python/gpibinter.c
+++ b/linux-gpib-user/language/python/gpibinter.c
@@ -3,7 +3,7 @@
  * Python wrapper module for gpib library functions.
  ************************************************************/
 
-
+#define PY_SSIZE_T_CLEAN
 #include "Python.h"
 
 #ifdef USE_INES
@@ -283,7 +283,7 @@
 static PyObject* gpib_write(PyObject *self, PyObject *args)
 {
 	char *command;
-	int command_len;
+	Py_ssize_t command_len;
 	int  device;
 	int sta;
 
@@ -309,7 +309,7 @@
 static PyObject* gpib_write_async(PyObject *self, PyObject *args)
 {
 	char *command;
-	int  command_len;
+	Py_ssize_t  command_len;
 	int  device;
 	int  sta;
 
@@ -336,7 +336,7 @@
 static PyObject* gpib_command(PyObject *self, PyObject *args)
 {
 	char *command;
-	int  command_len;
+	Py_ssize_t  command_len;
 	int  device;
 	int  sta;