diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 987d98d..7be075b 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -1598,7 +1598,7 @@
     else if (PySlice_Check(item)) {
         Py_ssize_t start, stop, step, slicelength, i;
         size_t cur;
-        char* source_buf;
+        const char* source_buf;
         char* result_buf;
         PyObject* result;
 
@@ -1863,7 +1863,7 @@
 do_xstrip(PyBytesObject *self, int striptype, PyObject *sepobj)
 {
     Py_buffer vsep;
-    char *s = PyBytes_AS_STRING(self);
+    const char *s = PyBytes_AS_STRING(self);
     Py_ssize_t len = PyBytes_GET_SIZE(self);
     char *sep;
     Py_ssize_t seplen;
@@ -1903,7 +1903,7 @@
 Py_LOCAL_INLINE(PyObject *)
 do_strip(PyBytesObject *self, int striptype)
 {
-    char *s = PyBytes_AS_STRING(self);
+    const char *s = PyBytes_AS_STRING(self);
     Py_ssize_t len = PyBytes_GET_SIZE(self), i, j;
 
     i = 0;
@@ -2020,7 +2020,8 @@
                      PyObject *deletechars)
 /*[clinic end generated code: output=43be3437f1956211 input=0ecdf159f654233c]*/
 {
-    char *input, *output;
+    const char *input;
+    char *output;
     Py_buffer table_view = {NULL, NULL};
     Py_buffer del_table_view = {NULL, NULL};
     const char *table_chars;
@@ -2371,7 +2372,7 @@
 bytes_hex_impl(PyBytesObject *self, PyObject *sep, int bytes_per_sep)
 /*[clinic end generated code: output=1f134da504064139 input=f1238d3455990218]*/
 {
-    char* argbuf = PyBytes_AS_STRING(self);
+    const char *argbuf = PyBytes_AS_STRING(self);
     Py_ssize_t arglen = PyBytes_GET_SIZE(self);
     return _Py_strhex_with_sep(argbuf, arglen, sep, bytes_per_sep);
 }
@@ -3188,7 +3189,7 @@
 Py_LOCAL_INLINE(Py_ssize_t)
 _PyBytesWriter_GetSize(_PyBytesWriter *writer, char *str)
 {
-    char *start = _PyBytesWriter_AsString(writer);
+    const char *start = _PyBytesWriter_AsString(writer);
     assert(str != NULL);
     assert(str >= start);
     assert(str - start <= writer->allocated);
@@ -3199,7 +3200,7 @@
 Py_LOCAL_INLINE(int)
 _PyBytesWriter_CheckConsistency(_PyBytesWriter *writer, char *str)
 {
-    char *start, *end;
+    const char *start, *end;
 
     if (writer->use_small_buffer) {
         assert(writer->buffer == NULL);
diff --git a/Objects/fileobject.c b/Objects/fileobject.c
index 840d17b..b8ec56e 100644
--- a/Objects/fileobject.c
+++ b/Objects/fileobject.c
@@ -76,7 +76,7 @@
     }
 
     if (n < 0 && result != NULL && PyBytes_Check(result)) {
-        char *s = PyBytes_AS_STRING(result);
+        const char *s = PyBytes_AS_STRING(result);
         Py_ssize_t len = PyBytes_GET_SIZE(result);
         if (len == 0) {
             Py_DECREF(result);
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 5d225cb..a66e1c4 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -5071,7 +5071,7 @@
     if (PyUnicode_Check(x))
         return PyLong_FromUnicodeObject(x, (int)base);
     else if (PyByteArray_Check(x) || PyBytes_Check(x)) {
-        char *string;
+        const char *string;
         if (PyByteArray_Check(x))
             string = PyByteArray_AS_STRING(x);
         else
diff --git a/Objects/stringlib/join.h b/Objects/stringlib/join.h
index 8ad598a..53bcbde 100644
--- a/Objects/stringlib/join.h
+++ b/Objects/stringlib/join.h
@@ -7,8 +7,8 @@
 Py_LOCAL_INLINE(PyObject *)
 STRINGLIB(bytes_join)(PyObject *sep, PyObject *iterable)
 {
-    char *sepstr = STRINGLIB_STR(sep);
-    const Py_ssize_t seplen = STRINGLIB_LEN(sep);
+    const char *sepstr = STRINGLIB_STR(sep);
+    Py_ssize_t seplen = STRINGLIB_LEN(sep);
     PyObject *res = NULL;
     char *p;
     Py_ssize_t seqlen = 0;
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 3c79feb..7f39022 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -3887,7 +3887,7 @@
     PyObject *path = NULL;
     PyObject *output = NULL;
     Py_ssize_t size;
-    void *data;
+    const char *data;
     if (arg == NULL) {
         Py_DECREF(*(PyObject**)addr);
         *(PyObject**)addr = NULL;
@@ -4718,7 +4718,7 @@
     unsigned int base64bits = 0;
     unsigned long base64buffer = 0;
     char * out;
-    char * start;
+    const char * start;
 
     if (PyUnicode_READY(str) == -1)
         return NULL;
@@ -5446,7 +5446,7 @@
         return -1;
     }
 
-    char *start = writer.use_small_buffer ? writer.small_buffer :
+    const char *start = writer.use_small_buffer ? writer.small_buffer :
                     PyBytes_AS_STRING(writer.buffer);
     Py_ssize_t len = end - start;