diff -up tre-c2f5d130c91b1696385a6ae0b5bcfd5214bcc9ca/python/tre-python.c.pep623 tre-c2f5d130c91b1696385a6ae0b5bcfd5214bcc9ca/python/tre-python.c
--- tre-c2f5d130c91b1696385a6ae0b5bcfd5214bcc9ca/python/tre-python.c.pep623	2023-09-28 18:14:11.839914165 +0200
+++ tre-c2f5d130c91b1696385a6ae0b5bcfd5214bcc9ca/python/tre-python.c	2023-09-28 18:26:22.469156493 +0200
@@ -365,7 +365,7 @@ PyTrePattern_search(TrePatternObject *se
 
   if (PyUnicode_Check(pstring))
     {
-      Py_ssize_t len = PyUnicode_GetSize(pstring);
+      Py_ssize_t len = PyUnicode_GetLength(pstring);
       wchar_t *buf = calloc(sizeof(wchar_t), len);
       if(!buf)
         {
@@ -502,7 +502,7 @@ PyTre_ncompile(PyObject *self, PyObject
 
   if (upattern != NULL)
     {
-      Py_ssize_t len = PyUnicode_GetSize(upattern);
+      Py_ssize_t len = PyUnicode_GetLength(upattern);
       wchar_t *buf = calloc(sizeof(wchar_t), len);
       if(!buf)
         {