bpo-33012: Fix invalid function cast warnings with gcc 8. (GH-6749)

Fix invalid function cast warnings with gcc 8
for method conventions different from METH_NOARGS, METH_O and
METH_VARARGS excluding Argument Clinic generated code.

27 files changed, 136 insertions, 136 deletions

diff --git a/Modules/_bisectmodule.c b/Modules/_bisectmodule.c
index 7dd73f9..461a11f 100644
--- a/Modules/_bisectmodule.c
+++ b/Modules/_bisectmodule.c
@@ -241,13 +241,13 @@ Optional args lo (default 0) and hi (default len(a)) bound the\n\
 slice of a to be searched.\n");
 
 static PyMethodDef bisect_methods[] = {
-    {"bisect_right", (PyCFunction)bisect_right,
+    {"bisect_right", (PyCFunction)(void(*)(void))bisect_right,
         METH_VARARGS|METH_KEYWORDS, bisect_right_doc},
-    {"insort_right", (PyCFunction)insort_right,
+    {"insort_right", (PyCFunction)(void(*)(void))insort_right,
         METH_VARARGS|METH_KEYWORDS, insort_right_doc},
-    {"bisect_left", (PyCFunction)bisect_left,
+    {"bisect_left", (PyCFunction)(void(*)(void))bisect_left,
         METH_VARARGS|METH_KEYWORDS, bisect_left_doc},
-    {"insort_left", (PyCFunction)insort_left,
+    {"insort_left", (PyCFunction)(void(*)(void))insort_left,
         METH_VARARGS|METH_KEYWORDS, insort_left_doc},
     {NULL, NULL} /* sentinel */
 };
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index a495e5f..1ad4a03 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -1573,9 +1573,9 @@ static PyMethodDef deque_methods[] = {
         METH_O,                  extend_doc},
     {"extendleft",              (PyCFunction)deque_extendleft,
         METH_O,                  extendleft_doc},
-    {"index",                   (PyCFunction)deque_index,
+    {"index",                   (PyCFunction)(void(*)(void))deque_index,
         METH_FASTCALL,            index_doc},
-    {"insert",                  (PyCFunction)deque_insert,
+    {"insert",                  (PyCFunction)(void(*)(void))deque_insert,
         METH_FASTCALL,            insert_doc},
     {"pop",                     (PyCFunction)deque_pop,
         METH_NOARGS,             pop_doc},
@@ -1589,7 +1589,7 @@ static PyMethodDef deque_methods[] = {
         METH_NOARGS,             reversed_doc},
     {"reverse",                 (PyCFunction)deque_reverse,
         METH_NOARGS,             reverse_doc},
-    {"rotate",                  (PyCFunction)deque_rotate,
+    {"rotate",                  (PyCFunction)(void(*)(void))deque_rotate,
         METH_FASTCALL,            rotate_doc},
     {"__sizeof__",              (PyCFunction)deque_sizeof,
         METH_NOARGS,             sizeof_doc},
diff --git a/Modules/_csv.c b/Modules/_csv.c
index 4cc1f7c..b4e92de 100644
--- a/Modules/_csv.c
+++ b/Modules/_csv.c
@@ -1583,13 +1583,13 @@ PyDoc_STRVAR(csv_field_size_limit_doc,
 "the old limit is returned");
 
 static struct PyMethodDef csv_methods[] = {
-    { "reader", (PyCFunction)csv_reader,
+    { "reader", (PyCFunction)(void(*)(void))csv_reader,
         METH_VARARGS | METH_KEYWORDS, csv_reader_doc},
-    { "writer", (PyCFunction)csv_writer,
+    { "writer", (PyCFunction)(void(*)(void))csv_writer,
         METH_VARARGS | METH_KEYWORDS, csv_writer_doc},
     { "list_dialects", (PyCFunction)csv_list_dialects,
         METH_NOARGS, csv_list_dialects_doc},
-    { "register_dialect", (PyCFunction)csv_register_dialect,
+    { "register_dialect", (PyCFunction)(void(*)(void))csv_register_dialect,
         METH_VARARGS | METH_KEYWORDS, csv_register_dialect_doc},
     { "unregister_dialect", (PyCFunction)csv_unregister_dialect,
         METH_O, csv_unregister_dialect_doc},
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index 0054ea8..eb9c35d 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -3255,7 +3255,7 @@ static PyMethodDef date_methods[] = {
     {"ctime",       (PyCFunction)date_ctime,        METH_NOARGS,
      PyDoc_STR("Return ctime() style string.")},
 
-    {"strftime",        (PyCFunction)date_strftime,     METH_VARARGS | METH_KEYWORDS,
+    {"strftime",        (PyCFunction)(void(*)(void))date_strftime,     METH_VARARGS | METH_KEYWORDS,
      PyDoc_STR("format -> strftime() style string.")},
 
     {"__format__",      (PyCFunction)date_format,       METH_VARARGS,
@@ -3283,7 +3283,7 @@ static PyMethodDef date_methods[] = {
      PyDoc_STR("Return the day of the week represented by the date.\n"
                "Monday == 0 ... Sunday == 6")},
 
-    {"replace",     (PyCFunction)date_replace,      METH_VARARGS | METH_KEYWORDS,
+    {"replace",     (PyCFunction)(void(*)(void))date_replace,      METH_VARARGS | METH_KEYWORDS,
      PyDoc_STR("Return date with new specified fields.")},
 
     {"__reduce__", (PyCFunction)date_reduce,        METH_NOARGS,
@@ -4392,12 +4392,12 @@ time_reduce(PyDateTime_Time *self, PyObject *arg)
 
 static PyMethodDef time_methods[] = {
 
-    {"isoformat",   (PyCFunction)time_isoformat,        METH_VARARGS | METH_KEYWORDS,
+    {"isoformat",   (PyCFunction)(void(*)(void))time_isoformat,        METH_VARARGS | METH_KEYWORDS,
      PyDoc_STR("Return string in ISO 8601 format, [HH[:MM[:SS[.mmm[uuu]]]]]"
                "[+HH:MM].\n\n"
                "timespec specifies what components of the time to include.\n")},
 
-    {"strftime",        (PyCFunction)time_strftime,     METH_VARARGS | METH_KEYWORDS,
+    {"strftime",        (PyCFunction)(void(*)(void))time_strftime,     METH_VARARGS | METH_KEYWORDS,
      PyDoc_STR("format -> strftime() style string.")},
 
     {"__format__",      (PyCFunction)date_format,       METH_VARARGS,
@@ -4412,7 +4412,7 @@ static PyMethodDef time_methods[] = {
     {"dst",             (PyCFunction)time_dst,          METH_NOARGS,
      PyDoc_STR("Return self.tzinfo.dst(self).")},
 
-    {"replace",     (PyCFunction)time_replace,          METH_VARARGS | METH_KEYWORDS,
+    {"replace",     (PyCFunction)(void(*)(void))time_replace,          METH_VARARGS | METH_KEYWORDS,
      PyDoc_STR("Return time with new specified fields.")},
 
      {"fromisoformat", (PyCFunction)time_fromisoformat, METH_O | METH_CLASS,
@@ -6025,7 +6025,7 @@ static PyMethodDef datetime_methods[] = {
      METH_NOARGS | METH_CLASS,
      PyDoc_STR("Return a new datetime representing UTC day and time.")},
 
-    {"fromtimestamp", (PyCFunction)datetime_fromtimestamp,
+    {"fromtimestamp", (PyCFunction)(void(*)(void))datetime_fromtimestamp,
      METH_VARARGS | METH_KEYWORDS | METH_CLASS,
      PyDoc_STR("timestamp[, tz] -> tz's local time from POSIX timestamp.")},
 
@@ -6038,7 +6038,7 @@ static PyMethodDef datetime_methods[] = {
      PyDoc_STR("string, format -> new datetime parsed from a string "
                "(like time.strptime()).")},
 
-    {"combine", (PyCFunction)datetime_combine,
+    {"combine", (PyCFunction)(void(*)(void))datetime_combine,
      METH_VARARGS | METH_KEYWORDS | METH_CLASS,
      PyDoc_STR("date, time -> datetime with same date and time fields")},
 
@@ -6069,7 +6069,7 @@ static PyMethodDef datetime_methods[] = {
     {"utctimetuple",   (PyCFunction)datetime_utctimetuple, METH_NOARGS,
      PyDoc_STR("Return UTC time tuple, compatible with time.localtime().")},
 
-    {"isoformat",   (PyCFunction)datetime_isoformat, METH_VARARGS | METH_KEYWORDS,
+    {"isoformat",   (PyCFunction)(void(*)(void))datetime_isoformat, METH_VARARGS | METH_KEYWORDS,
      PyDoc_STR("[sep] -> string in ISO 8601 format, "
                "YYYY-MM-DDT[HH[:MM[:SS[.mmm[uuu]]]]][+HH:MM].\n"
                "sep is used to separate the year from the time, and "
@@ -6087,10 +6087,10 @@ static PyMethodDef datetime_methods[] = {
     {"dst",             (PyCFunction)datetime_dst, METH_NOARGS,
      PyDoc_STR("Return self.tzinfo.dst(self).")},
 
-    {"replace",     (PyCFunction)datetime_replace,      METH_VARARGS | METH_KEYWORDS,
+    {"replace",     (PyCFunction)(void(*)(void))datetime_replace,      METH_VARARGS | METH_KEYWORDS,
      PyDoc_STR("Return datetime with new specified fields.")},
 
-    {"astimezone",  (PyCFunction)datetime_astimezone, METH_VARARGS | METH_KEYWORDS,
+    {"astimezone",  (PyCFunction)(void(*)(void))datetime_astimezone, METH_VARARGS | METH_KEYWORDS,
      PyDoc_STR("tz -> convert to local time in new timezone tz\n")},
 
     {"__reduce_ex__", (PyCFunction)datetime_reduce_ex,     METH_VARARGS,
diff --git a/Modules/_decimal/_decimal.c b/Modules/_decimal/_decimal.c
index 1e58d3d..51aed2c 100644
--- a/Modules/_decimal/_decimal.c
+++ b/Modules/_decimal/_decimal.c
@@ -4598,30 +4598,30 @@ static PyNumberMethods dec_number_methods =
 static PyMethodDef dec_methods [] =
 {
   /* Unary arithmetic functions, optional context arg */
-  { "exp", (PyCFunction)dec_mpd_qexp, METH_VARARGS|METH_KEYWORDS, doc_exp },
-  { "ln", (PyCFunction)dec_mpd_qln, METH_VARARGS|METH_KEYWORDS, doc_ln },
-  { "log10", (PyCFunction)dec_mpd_qlog10, METH_VARARGS|METH_KEYWORDS, doc_log10 },
-  { "next_minus", (PyCFunction)dec_mpd_qnext_minus, METH_VARARGS|METH_KEYWORDS, doc_next_minus },
-  { "next_plus", (PyCFunction)dec_mpd_qnext_plus, METH_VARARGS|METH_KEYWORDS, doc_next_plus },
-  { "normalize", (PyCFunction)dec_mpd_qreduce, METH_VARARGS|METH_KEYWORDS, doc_normalize },
-  { "to_integral", (PyCFunction)PyDec_ToIntegralValue, METH_VARARGS|METH_KEYWORDS, doc_to_integral },
-  { "to_integral_exact", (PyCFunction)PyDec_ToIntegralExact, METH_VARARGS|METH_KEYWORDS, doc_to_integral_exact },
-  { "to_integral_value", (PyCFunction)PyDec_ToIntegralValue, METH_VARARGS|METH_KEYWORDS, doc_to_integral_value },
-  { "sqrt", (PyCFunction)dec_mpd_qsqrt, METH_VARARGS|METH_KEYWORDS, doc_sqrt },
+  { "exp", (PyCFunction)(void(*)(void))dec_mpd_qexp, METH_VARARGS|METH_KEYWORDS, doc_exp },
+  { "ln", (PyCFunction)(void(*)(void))dec_mpd_qln, METH_VARARGS|METH_KEYWORDS, doc_ln },
+  { "log10", (PyCFunction)(void(*)(void))dec_mpd_qlog10, METH_VARARGS|METH_KEYWORDS, doc_log10 },
+  { "next_minus", (PyCFunction)(void(*)(void))dec_mpd_qnext_minus, METH_VARARGS|METH_KEYWORDS, doc_next_minus },
+  { "next_plus", (PyCFunction)(void(*)(void))dec_mpd_qnext_plus, METH_VARARGS|METH_KEYWORDS, doc_next_plus },
+  { "normalize", (PyCFunction)(void(*)(void))dec_mpd_qreduce, METH_VARARGS|METH_KEYWORDS, doc_normalize },
+  { "to_integral", (PyCFunction)(void(*)(void))PyDec_ToIntegralValue, METH_VARARGS|METH_KEYWORDS, doc_to_integral },
+  { "to_integral_exact", (PyCFunction)(void(*)(void))PyDec_ToIntegralExact, METH_VARARGS|METH_KEYWORDS, doc_to_integral_exact },
+  { "to_integral_value", (PyCFunction)(void(*)(void))PyDec_ToIntegralValue, METH_VARARGS|METH_KEYWORDS, doc_to_integral_value },
+  { "sqrt", (PyCFunction)(void(*)(void))dec_mpd_qsqrt, METH_VARARGS|METH_KEYWORDS, doc_sqrt },
 
   /* Binary arithmetic functions, optional context arg */
-  { "compare", (PyCFunction)dec_mpd_qcompare, METH_VARARGS|METH_KEYWORDS, doc_compare },
-  { "compare_signal", (PyCFunction)dec_mpd_qcompare_signal, METH_VARARGS|METH_KEYWORDS, doc_compare_signal },
-  { "max", (PyCFunction)dec_mpd_qmax, METH_VARARGS|METH_KEYWORDS, doc_max },
-  { "max_mag", (PyCFunction)dec_mpd_qmax_mag, METH_VARARGS|METH_KEYWORDS, doc_max_mag },
-  { "min", (PyCFunction)dec_mpd_qmin, METH_VARARGS|METH_KEYWORDS, doc_min },
-  { "min_mag", (PyCFunction)dec_mpd_qmin_mag, METH_VARARGS|METH_KEYWORDS, doc_min_mag },
-  { "next_toward", (PyCFunction)dec_mpd_qnext_toward, METH_VARARGS|METH_KEYWORDS, doc_next_toward },
-  { "quantize", (PyCFunction)dec_mpd_qquantize, METH_VARARGS|METH_KEYWORDS, doc_quantize },
-  { "remainder_near", (PyCFunction)dec_mpd_qrem_near, METH_VARARGS|METH_KEYWORDS, doc_remainder_near },
+  { "compare", (PyCFunction)(void(*)(void))dec_mpd_qcompare, METH_VARARGS|METH_KEYWORDS, doc_compare },
+  { "compare_signal", (PyCFunction)(void(*)(void))dec_mpd_qcompare_signal, METH_VARARGS|METH_KEYWORDS, doc_compare_signal },
+  { "max", (PyCFunction)(void(*)(void))dec_mpd_qmax, METH_VARARGS|METH_KEYWORDS, doc_max },
+  { "max_mag", (PyCFunction)(void(*)(void))dec_mpd_qmax_mag, METH_VARARGS|METH_KEYWORDS, doc_max_mag },
+  { "min", (PyCFunction)(void(*)(void))dec_mpd_qmin, METH_VARARGS|METH_KEYWORDS, doc_min },
+  { "min_mag", (PyCFunction)(void(*)(void))dec_mpd_qmin_mag, METH_VARARGS|METH_KEYWORDS, doc_min_mag },
+  { "next_toward", (PyCFunction)(void(*)(void))dec_mpd_qnext_toward, METH_VARARGS|METH_KEYWORDS, doc_next_toward },
+  { "quantize", (PyCFunction)(void(*)(void))dec_mpd_qquantize, METH_VARARGS|METH_KEYWORDS, doc_quantize },
+  { "remainder_near", (PyCFunction)(void(*)(void))dec_mpd_qrem_near, METH_VARARGS|METH_KEYWORDS, doc_remainder_near },
 
   /* Ternary arithmetic functions, optional context arg */
-  { "fma", (PyCFunction)dec_mpd_qfma, METH_VARARGS|METH_KEYWORDS, doc_fma },
+  { "fma", (PyCFunction)(void(*)(void))dec_mpd_qfma, METH_VARARGS|METH_KEYWORDS, doc_fma },
 
   /* Boolean functions, no context arg */
   { "is_canonical", dec_mpd_iscanonical, METH_NOARGS, doc_is_canonical },
@@ -4634,8 +4634,8 @@ static PyMethodDef dec_methods [] =
   { "is_zero", dec_mpd_iszero, METH_NOARGS, doc_is_zero },
 
   /* Boolean functions, optional context arg */
-  { "is_normal", (PyCFunction)dec_mpd_isnormal, METH_VARARGS|METH_KEYWORDS, doc_is_normal },
-  { "is_subnormal", (PyCFunction)dec_mpd_issubnormal, METH_VARARGS|METH_KEYWORDS, doc_is_subnormal },
+  { "is_normal", (PyCFunction)(void(*)(void))dec_mpd_isnormal, METH_VARARGS|METH_KEYWORDS, doc_is_normal },
+  { "is_subnormal", (PyCFunction)(void(*)(void))dec_mpd_issubnormal, METH_VARARGS|METH_KEYWORDS, doc_is_subnormal },
 
   /* Unary functions, no context arg */
   { "adjusted", dec_mpd_adjexp, METH_NOARGS, doc_adjusted },
@@ -4648,24 +4648,24 @@ static PyMethodDef dec_methods [] =
   { "copy_negate", dec_mpd_qcopy_negate, METH_NOARGS, doc_copy_negate },
 
   /* Unary functions, optional context arg */
-  { "logb", (PyCFunction)dec_mpd_qlogb, METH_VARARGS|METH_KEYWORDS, doc_logb },
-  { "logical_invert", (PyCFunction)dec_mpd_qinvert, METH_VARARGS|METH_KEYWORDS, doc_logical_invert },
-  { "number_class", (PyCFunction)dec_mpd_class, METH_VARARGS|METH_KEYWORDS, doc_number_class },
-  { "to_eng_string", (PyCFunction)dec_mpd_to_eng, METH_VARARGS|METH_KEYWORDS, doc_to_eng_string },
+  { "logb", (PyCFunction)(void(*)(void))dec_mpd_qlogb, METH_VARARGS|METH_KEYWORDS, doc_logb },
+  { "logical_invert", (PyCFunction)(void(*)(void))dec_mpd_qinvert, METH_VARARGS|METH_KEYWORDS, doc_logical_invert },
+  { "number_class", (PyCFunction)(void(*)(void))dec_mpd_class, METH_VARARGS|METH_KEYWORDS, doc_number_class },
+  { "to_eng_string", (PyCFunction)(void(*)(void))dec_mpd_to_eng, METH_VARARGS|METH_KEYWORDS, doc_to_eng_string },
 
   /* Binary functions, optional context arg for conversion errors */
-  { "compare_total", (PyCFunction)dec_mpd_compare_total, METH_VARARGS|METH_KEYWORDS, doc_compare_total },
-  { "compare_total_mag", (PyCFunction)dec_mpd_compare_total_mag, METH_VARARGS|METH_KEYWORDS, doc_compare_total_mag },
-  { "copy_sign", (PyCFunction)dec_mpd_qcopy_sign, METH_VARARGS|METH_KEYWORDS, doc_copy_sign },
-  { "same_quantum", (PyCFunction)dec_mpd_same_quantum, METH_VARARGS|METH_KEYWORDS, doc_same_quantum },
+  { "compare_total", (PyCFunction)(void(*)(void))dec_mpd_compare_total, METH_VARARGS|METH_KEYWORDS, doc_compare_total },
+  { "compare_total_mag", (PyCFunction)(void(*)(void))dec_mpd_compare_total_mag, METH_VARARGS|METH_KEYWORDS, doc_compare_total_mag },
+  { "copy_sign", (PyCFunction)(void(*)(void))dec_mpd_qcopy_sign, METH_VARARGS|METH_KEYWORDS, doc_copy_sign },
+  { "same_quantum", (PyCFunction)(void(*)(void))dec_mpd_same_quantum, METH_VARARGS|METH_KEYWORDS, doc_same_quantum },
 
   /* Binary functions, optional context arg */
-  { "logical_and", (PyCFunction)dec_mpd_qand, METH_VARARGS|METH_KEYWORDS, doc_logical_and },
-  { "logical_or", (PyCFunction)dec_mpd_qor, METH_VARARGS|METH_KEYWORDS, doc_logical_or },
-  { "logical_xor", (PyCFunction)dec_mpd_qxor, METH_VARARGS|METH_KEYWORDS, doc_logical_xor },
-  { "rotate", (PyCFunction)dec_mpd_qrotate, METH_VARARGS|METH_KEYWORDS, doc_rotate },
-  { "scaleb", (PyCFunction)dec_mpd_qscaleb, METH_VARARGS|METH_KEYWORDS, doc_scaleb },
-  { "shift", (PyCFunction)dec_mpd_qshift, METH_VARARGS|METH_KEYWORDS, doc_shift },
+  { "logical_and", (PyCFunction)(void(*)(void))dec_mpd_qand, METH_VARARGS|METH_KEYWORDS, doc_logical_and },
+  { "logical_or", (PyCFunction)(void(*)(void))dec_mpd_qor, METH_VARARGS|METH_KEYWORDS, doc_logical_or },
+  { "logical_xor", (PyCFunction)(void(*)(void))dec_mpd_qxor, METH_VARARGS|METH_KEYWORDS, doc_logical_xor },
+  { "rotate", (PyCFunction)(void(*)(void))dec_mpd_qrotate, METH_VARARGS|METH_KEYWORDS, doc_rotate },
+  { "scaleb", (PyCFunction)(void(*)(void))dec_mpd_qscaleb, METH_VARARGS|METH_KEYWORDS, doc_scaleb },
+  { "shift", (PyCFunction)(void(*)(void))dec_mpd_qshift, METH_VARARGS|METH_KEYWORDS, doc_shift },
 
   /* Miscellaneous */
   { "from_float", dec_from_float, METH_O|METH_CLASS, doc_from_float },
@@ -5303,7 +5303,7 @@ static PyMethodDef context_methods [] =
   { "subtract", ctx_mpd_qsub, METH_VARARGS, doc_ctx_subtract },
 
   /* Binary or ternary arithmetic functions */
-  { "power", (PyCFunction)ctx_mpd_qpow, METH_VARARGS|METH_KEYWORDS, doc_ctx_power },
+  { "power", (PyCFunction)(void(*)(void))ctx_mpd_qpow, METH_VARARGS|METH_KEYWORDS, doc_ctx_power },
 
   /* Ternary arithmetic functions */
   { "fma", ctx_mpd_qfma, METH_VARARGS, doc_ctx_fma },
@@ -5421,7 +5421,7 @@ static PyMethodDef _decimal_methods [] =
 {
   { "getcontext", (PyCFunction)PyDec_GetCurrentContext, METH_NOARGS, doc_getcontext},
   { "setcontext", (PyCFunction)PyDec_SetCurrentContext, METH_O, doc_setcontext},
-  { "localcontext", (PyCFunction)ctxmanager_new, METH_VARARGS|METH_KEYWORDS, doc_localcontext},
+  { "localcontext", (PyCFunction)(void(*)(void))ctxmanager_new, METH_VARARGS|METH_KEYWORDS, doc_localcontext},
 #ifdef EXTRA_FUNCTIONALITY
   { "IEEEContext", (PyCFunction)ieee_context, METH_O, doc_ieee_context},
 #endif
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 2f1c4c0..62374d8 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -3968,7 +3968,7 @@ static PyTypeObject XMLParser_Type = {
 /* python module interface */
 
 static PyMethodDef _functions[] = {
-    {"SubElement", (PyCFunction) subelement, METH_VARARGS | METH_KEYWORDS},
+    {"SubElement", (PyCFunction)(void(*)(void)) subelement, METH_VARARGS | METH_KEYWORDS},
     {NULL, NULL}
 };
 
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 8701f6c..0fb4847 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1236,7 +1236,7 @@ PyDoc_STRVAR(module_doc,
 
 static PyMethodDef module_methods[] = {
     {"reduce",          functools_reduce,     METH_VARARGS, functools_reduce_doc},
-    {"cmp_to_key",      (PyCFunction)functools_cmp_to_key,
+    {"cmp_to_key",      (PyCFunction)(void(*)(void))functools_cmp_to_key,
      METH_VARARGS | METH_KEYWORDS, functools_cmp_to_key_doc},
     {NULL,              NULL}           /* sentinel */
 };
diff --git a/Modules/_hashopenssl.c b/Modules/_hashopenssl.c
index 42ea997..d7e613c 100644
--- a/Modules/_hashopenssl.c
+++ b/Modules/_hashopenssl.c
@@ -1011,7 +1011,7 @@ generate_hash_name_list(void)
 
 /* a PyMethodDef structure for the constructor */
 #define CONSTRUCTOR_METH_DEF(NAME)  \
-    {"openssl_" #NAME, (PyCFunction)EVP_new_ ## NAME, METH_FASTCALL, \
+    {"openssl_" #NAME, (PyCFunction)(void(*)(void))EVP_new_ ## NAME, METH_FASTCALL, \
         PyDoc_STR("Returns a " #NAME \
                   " hash object; optionally initialized with a string") \
     }
@@ -1034,9 +1034,9 @@ GEN_CONSTRUCTOR(sha512)
 /* List of functions exported by this module */
 
 static struct PyMethodDef EVP_functions[] = {
-    {"new", (PyCFunction)EVP_new, METH_VARARGS|METH_KEYWORDS, EVP_new__doc__},
+    {"new", (PyCFunction)(void(*)(void))EVP_new, METH_VARARGS|METH_KEYWORDS, EVP_new__doc__},
 #ifdef PY_PBKDF2_HMAC
-    {"pbkdf2_hmac", (PyCFunction)pbkdf2_hmac, METH_VARARGS|METH_KEYWORDS,
+    {"pbkdf2_hmac", (PyCFunction)(void(*)(void))pbkdf2_hmac, METH_VARARGS|METH_KEYWORDS,
      pbkdf2_hmac__doc__},
 #endif
     _HASHLIB_SCRYPT_METHODDEF
diff --git a/Modules/_lsprof.c b/Modules/_lsprof.c
index 233f62f..4508f5e 100644
--- a/Modules/_lsprof.c
+++ b/Modules/_lsprof.c
@@ -778,7 +778,7 @@ profiler_init(ProfilerObject *pObj, PyObject *args, PyObject *kw)
 static PyMethodDef profiler_methods[] = {
     {"getstats",    (PyCFunction)profiler_getstats,
                     METH_NOARGS,                        getstats_doc},
-    {"enable",          (PyCFunction)profiler_enable,
+    {"enable",          (PyCFunction)(void(*)(void))profiler_enable,
                     METH_VARARGS | METH_KEYWORDS,       enable_doc},
     {"disable",         (PyCFunction)profiler_disable,
                     METH_NOARGS,                        disable_doc},
diff --git a/Modules/_multiprocessing/semaphore.c b/Modules/_multiprocessing/semaphore.c
index b1d3a21..e15adfb 100644
--- a/Modules/_multiprocessing/semaphore.c
+++ b/Modules/_multiprocessing/semaphore.c
@@ -581,11 +581,11 @@ semlock_afterfork(SemLockObject *self, PyObject *Py_UNUSED(ignored))
  */
 
 static PyMethodDef semlock_methods[] = {
-    {"acquire", (PyCFunction)semlock_acquire, METH_VARARGS | METH_KEYWORDS,
+    {"acquire", (PyCFunction)(void(*)(void))semlock_acquire, METH_VARARGS | METH_KEYWORDS,
      "acquire the semaphore/lock"},
     {"release", (PyCFunction)semlock_release, METH_NOARGS,
      "release the semaphore/lock"},
-    {"__enter__", (PyCFunction)semlock_acquire, METH_VARARGS | METH_KEYWORDS,
+    {"__enter__", (PyCFunction)(void(*)(void))semlock_acquire, METH_VARARGS | METH_KEYWORDS,
      "enter the semaphore/lock"},
     {"__exit__", (PyCFunction)semlock_release, METH_VARARGS,
      "exit the semaphore/lock"},
diff --git a/Modules/_sqlite/connection.c b/Modules/_sqlite/connection.c
index 89a8751..65e8df4 100644
--- a/Modules/_sqlite/connection.c
+++ b/Modules/_sqlite/connection.c
@@ -1764,7 +1764,7 @@ static PyGetSetDef connection_getset[] = {
 };
 
 static PyMethodDef connection_methods[] = {
-    {"cursor", (PyCFunction)pysqlite_connection_cursor, METH_VARARGS|METH_KEYWORDS,
+    {"cursor", (PyCFunction)(void(*)(void))pysqlite_connection_cursor, METH_VARARGS|METH_KEYWORDS,
         PyDoc_STR("Return a cursor for the connection.")},
     {"close", (PyCFunction)pysqlite_connection_close, METH_NOARGS,
         PyDoc_STR("Closes the connection.")},
@@ -1772,11 +1772,11 @@ static PyMethodDef connection_methods[] = {
         PyDoc_STR("Commit the current transaction.")},
     {"rollback", (PyCFunction)pysqlite_connection_rollback, METH_NOARGS,
         PyDoc_STR("Roll back the current transaction.")},
-    {"create_function", (PyCFunction)pysqlite_connection_create_function, METH_VARARGS|METH_KEYWORDS,
+    {"create_function", (PyCFunction)(void(*)(void))pysqlite_connection_create_function, METH_VARARGS|METH_KEYWORDS,
         PyDoc_STR("Creates a new function. Non-standard.")},
-    {"create_aggregate", (PyCFunction)pysqlite_connection_create_aggregate, METH_VARARGS|METH_KEYWORDS,
+    {"create_aggregate", (PyCFunction)(void(*)(void))pysqlite_connection_create_aggregate, METH_VARARGS|METH_KEYWORDS,
         PyDoc_STR("Creates a new aggregate. Non-standard.")},
-    {"set_authorizer", (PyCFunction)pysqlite_connection_set_authorizer, METH_VARARGS|METH_KEYWORDS,
+    {"set_authorizer", (PyCFunction)(void(*)(void))pysqlite_connection_set_authorizer, METH_VARARGS|METH_KEYWORDS,
         PyDoc_STR("Sets authorizer callback. Non-standard.")},
     #ifdef HAVE_LOAD_EXTENSION
     {"enable_load_extension", (PyCFunction)pysqlite_enable_load_extension, METH_VARARGS,
@@ -1784,9 +1784,9 @@ static PyMethodDef connection_methods[] = {
     {"load_extension", (PyCFunction)pysqlite_load_extension, METH_VARARGS,
         PyDoc_STR("Load SQLite extension module. Non-standard.")},
     #endif
-    {"set_progress_handler", (PyCFunction)pysqlite_connection_set_progress_handler, METH_VARARGS|METH_KEYWORDS,
+    {"set_progress_handler", (PyCFunction)(void(*)(void))pysqlite_connection_set_progress_handler, METH_VARARGS|METH_KEYWORDS,
         PyDoc_STR("Sets progress handler callback. Non-standard.")},
-    {"set_trace_callback", (PyCFunction)pysqlite_connection_set_trace_callback, METH_VARARGS|METH_KEYWORDS,
+    {"set_trace_callback", (PyCFunction)(void(*)(void))pysqlite_connection_set_trace_callback, METH_VARARGS|METH_KEYWORDS,
         PyDoc_STR("Sets a trace callback called for each SQL statement (passed as unicode). Non-standard.")},
     {"execute", (PyCFunction)pysqlite_connection_execute, METH_VARARGS,
         PyDoc_STR("Executes a SQL statement. Non-standard.")},
@@ -1801,7 +1801,7 @@ static PyMethodDef connection_methods[] = {
     {"iterdump", (PyCFunction)pysqlite_connection_iterdump, METH_NOARGS,
         PyDoc_STR("Returns iterator to the dump of the database in an SQL text format. Non-standard.")},
     #ifdef HAVE_BACKUP_API
-    {"backup", (PyCFunction)pysqlite_connection_backup, METH_VARARGS | METH_KEYWORDS,
+    {"backup", (PyCFunction)(void(*)(void))pysqlite_connection_backup, METH_VARARGS | METH_KEYWORDS,
         PyDoc_STR("Makes a backup of the database. Non-standard.")},
     #endif
     {"__enter__", (PyCFunction)pysqlite_connection_enter, METH_NOARGS,
diff --git a/Modules/_sqlite/cursor.c b/Modules/_sqlite/cursor.c
index c62ad5d..8a46e5c 100644
--- a/Modules/_sqlite/cursor.c
+++ b/Modules/_sqlite/cursor.c
@@ -908,7 +908,7 @@ static PyMethodDef cursor_methods[] = {
         PyDoc_STR("Executes a multiple SQL statements at once. Non-standard.")},
     {"fetchone", (PyCFunction)pysqlite_cursor_fetchone, METH_NOARGS,
         PyDoc_STR("Fetches one row from the resultset.")},
-    {"fetchmany", (PyCFunction)pysqlite_cursor_fetchmany, METH_VARARGS|METH_KEYWORDS,
+    {"fetchmany", (PyCFunction)(void(*)(void))pysqlite_cursor_fetchmany, METH_VARARGS|METH_KEYWORDS,
         PyDoc_STR("Fetches several rows from the resultset.")},
     {"fetchall", (PyCFunction)pysqlite_cursor_fetchall, METH_NOARGS,
         PyDoc_STR("Fetches all rows from the resultset.")},
diff --git a/Modules/_sqlite/module.c b/Modules/_sqlite/module.c
index db2b495..274ee13 100644
--- a/Modules/_sqlite/module.c
+++ b/Modules/_sqlite/module.c
@@ -245,12 +245,12 @@ static void converters_init(PyObject* dict)
 }
 
 static PyMethodDef module_methods[] = {
-    {"connect",  (PyCFunction)module_connect,
+    {"connect",  (PyCFunction)(void(*)(void))module_connect,
      METH_VARARGS | METH_KEYWORDS, module_connect_doc},
-    {"complete_statement",  (PyCFunction)module_complete,
+    {"complete_statement",  (PyCFunction)(void(*)(void))module_complete,
      METH_VARARGS | METH_KEYWORDS, module_complete_doc},
 #ifdef HAVE_SHARED_CACHE
-    {"enable_shared_cache",  (PyCFunction)module_enable_shared_cache,
+    {"enable_shared_cache",  (PyCFunction)(void(*)(void))module_enable_shared_cache,
      METH_VARARGS | METH_KEYWORDS, module_enable_shared_cache_doc},
 #endif
     {"register_adapter", (PyCFunction)module_register_adapter,
diff --git a/Modules/_struct.c b/Modules/_struct.c
index 0be52d9..6767330 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -2006,8 +2006,8 @@ s_sizeof(PyStructObject *self, void *unused)
 
 static struct PyMethodDef s_methods[] = {
     STRUCT_ITER_UNPACK_METHODDEF
-    {"pack",            (PyCFunction)s_pack, METH_FASTCALL, s_pack__doc__},
-    {"pack_into",       (PyCFunction)s_pack_into, METH_FASTCALL, s_pack_into__doc__},
+    {"pack",            (PyCFunction)(void(*)(void))s_pack, METH_FASTCALL, s_pack__doc__},
+    {"pack_into",       (PyCFunction)(void(*)(void))s_pack_into, METH_FASTCALL, s_pack_into__doc__},
     STRUCT_UNPACK_METHODDEF
     STRUCT_UNPACK_FROM_METHODDEF
     {"__sizeof__",      (PyCFunction)s_sizeof, METH_NOARGS, s_sizeof__doc__},
@@ -2264,8 +2264,8 @@ static struct PyMethodDef module_functions[] = {
     _CLEARCACHE_METHODDEF
     CALCSIZE_METHODDEF
     ITER_UNPACK_METHODDEF
-    {"pack",            (PyCFunction)pack, METH_FASTCALL,   pack_doc},
-    {"pack_into",       (PyCFunction)pack_into, METH_FASTCALL,   pack_into_doc},
+    {"pack",            (PyCFunction)(void(*)(void))pack, METH_FASTCALL,   pack_doc},
+    {"pack_into",       (PyCFunction)(void(*)(void))pack_into, METH_FASTCALL,   pack_into_doc},
     UNPACK_METHODDEF
     UNPACK_FROM_METHODDEF
     {NULL,       NULL}          /* sentinel */
diff --git a/Modules/_testbuffer.c b/Modules/_testbuffer.c
index b1b8ff3..4ff44f9 100644
--- a/Modules/_testbuffer.c
+++ b/Modules/_testbuffer.c
@@ -2635,7 +2635,7 @@ static PyMethodDef ndarray_methods [] =
 {
     { "tolist", ndarray_tolist, METH_NOARGS, NULL },
     { "tobytes", ndarray_tobytes, METH_NOARGS, NULL },
-    { "push", (PyCFunction)ndarray_push, METH_VARARGS|METH_KEYWORDS, NULL },
+    { "push", (PyCFunction)(void(*)(void))ndarray_push, METH_VARARGS|METH_KEYWORDS, NULL },
     { "pop", ndarray_pop, METH_NOARGS, NULL },
     { "add_suboffsets", ndarray_add_suboffsets, METH_NOARGS, NULL },
     { "memoryview_from_buffer", ndarray_memoryview_from_buffer, METH_NOARGS, NULL },
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 4715f39..4933ef3 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -4787,14 +4787,14 @@ static PyMethodDef TestMethods[] = {
     {"getbuffer_with_null_view", getbuffer_with_null_view, METH_O},
     {"test_buildvalue_N",       test_buildvalue_N,               METH_NOARGS},
     {"get_args", get_args, METH_VARARGS},
-    {"get_kwargs", (PyCFunction)get_kwargs, METH_VARARGS|METH_KEYWORDS},
+    {"get_kwargs", (PyCFunction)(void(*)(void))get_kwargs, METH_VARARGS|METH_KEYWORDS},
     {"getargs_tuple",           getargs_tuple,                   METH_VARARGS},
-    {"getargs_keywords", (PyCFunction)getargs_keywords,
+    {"getargs_keywords", (PyCFunction)(void(*)(void))getargs_keywords,
       METH_VARARGS|METH_KEYWORDS},
-    {"getargs_keyword_only", (PyCFunction)getargs_keyword_only,
+    {"getargs_keyword_only", (PyCFunction)(void(*)(void))getargs_keyword_only,
       METH_VARARGS|METH_KEYWORDS},
     {"getargs_positional_only_and_keywords",
-      (PyCFunction)getargs_positional_only_and_keywords,
+      (PyCFunction)(void(*)(void))getargs_positional_only_and_keywords,
       METH_VARARGS|METH_KEYWORDS},
     {"getargs_b",               getargs_b,                       METH_VARARGS},
     {"getargs_B",               getargs_B,                       METH_VARARGS},
@@ -4863,7 +4863,7 @@ static PyMethodDef TestMethods[] = {
     {"set_exc_info",            test_set_exc_info,               METH_VARARGS},
     {"argparsing",              argparsing,                      METH_VARARGS},
     {"code_newempty",           code_newempty,                   METH_VARARGS},
-    {"make_exception_with_doc", (PyCFunction)make_exception_with_doc,
+    {"make_exception_with_doc", (PyCFunction)(void(*)(void))make_exception_with_doc,
      METH_VARARGS | METH_KEYWORDS},
     {"make_memoryview_from_NULL_pointer", make_memoryview_from_NULL_pointer,
      METH_NOARGS},
@@ -4960,7 +4960,7 @@ static PyMethodDef TestMethods[] = {
     {"get_mapping_items", get_mapping_items, METH_O},
     {"test_pythread_tss_key_state", test_pythread_tss_key_state, METH_VARARGS},
     {"hamt", new_hamt, METH_NOARGS},
-    {"bad_get", (PyCFunction)bad_get, METH_FASTCALL},
+    {"bad_get", (PyCFunction)(void(*)(void))bad_get, METH_FASTCALL},
     {"EncodeLocaleEx", encode_locale_ex, METH_VARARGS},
     {"DecodeLocaleEx", decode_locale_ex, METH_VARARGS},
     {"get_global_config", get_global_config, METH_NOARGS},
@@ -5388,7 +5388,7 @@ generic_alias_mro_entries(PyGenericAliasObject *self, PyObject *bases)
 }
 
 static PyMethodDef generic_alias_methods[] = {
-    {"__mro_entries__", (PyCFunction) generic_alias_mro_entries, METH_O, NULL},
+    {"__mro_entries__", (PyCFunction)(void(*)(void))generic_alias_mro_entries, METH_O, NULL},
     {NULL}  /* sentinel */
 };
 
diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index a4ddb87..d075ef7 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -204,9 +204,9 @@ lock_repr(lockobject *self)
 }
 
 static PyMethodDef lock_methods[] = {
-    {"acquire_lock", (PyCFunction)lock_PyThread_acquire_lock,
+    {"acquire_lock", (PyCFunction)(void(*)(void))lock_PyThread_acquire_lock,
      METH_VARARGS | METH_KEYWORDS, acquire_doc},
-    {"acquire",      (PyCFunction)lock_PyThread_acquire_lock,
+    {"acquire",      (PyCFunction)(void(*)(void))lock_PyThread_acquire_lock,
      METH_VARARGS | METH_KEYWORDS, acquire_doc},
     {"release_lock", (PyCFunction)lock_PyThread_release_lock,
      METH_NOARGS, release_doc},
@@ -216,7 +216,7 @@ static PyMethodDef lock_methods[] = {
      METH_NOARGS, locked_doc},
     {"locked",       (PyCFunction)lock_locked_lock,
      METH_NOARGS, locked_doc},
-    {"__enter__",    (PyCFunction)lock_PyThread_acquire_lock,
+    {"__enter__",    (PyCFunction)(void(*)(void))lock_PyThread_acquire_lock,
      METH_VARARGS | METH_KEYWORDS, acquire_doc},
     {"__exit__",    (PyCFunction)lock_PyThread_release_lock,
      METH_VARARGS, release_doc},
@@ -466,7 +466,7 @@ rlock_repr(rlockobject *self)
 
 
 static PyMethodDef rlock_methods[] = {
-    {"acquire",      (PyCFunction)rlock_acquire,
+    {"acquire",      (PyCFunction)(void(*)(void))rlock_acquire,
      METH_VARARGS | METH_KEYWORDS, rlock_acquire_doc},
     {"release",      (PyCFunction)rlock_release,
      METH_NOARGS, rlock_release_doc},
@@ -476,7 +476,7 @@ static PyMethodDef rlock_methods[] = {
      METH_VARARGS, rlock_acquire_restore_doc},
     {"_release_save", (PyCFunction)rlock_release_save,
      METH_NOARGS, rlock_release_save_doc},
-    {"__enter__",    (PyCFunction)rlock_acquire,
+    {"__enter__",    (PyCFunction)(void(*)(void))rlock_acquire,
      METH_VARARGS | METH_KEYWORDS, rlock_acquire_doc},
     {"__exit__",    (PyCFunction)rlock_release,
      METH_VARARGS, rlock_release_doc},
diff --git a/Modules/_xxsubinterpretersmodule.c b/Modules/_xxsubinterpretersmodule.c
index 33509ef..235df70 100644
--- a/Modules/_xxsubinterpretersmodule.c
+++ b/Modules/_xxsubinterpretersmodule.c
@@ -2768,7 +2768,7 @@ channel__channel_id(PyObject *self, PyObject *args, PyObject *kwds)
 static PyMethodDef module_functions[] = {
     {"create",                    (PyCFunction)interp_create,
      METH_VARARGS, create_doc},
-    {"destroy",                   (PyCFunction)interp_destroy,
+    {"destroy",                   (PyCFunction)(void(*)(void))interp_destroy,
      METH_VARARGS | METH_KEYWORDS, destroy_doc},
     {"list_all",                  interp_list_all,
      METH_NOARGS, list_all_doc},
@@ -2776,29 +2776,29 @@ static PyMethodDef module_functions[] = {
      METH_NOARGS, get_current_doc},
     {"get_main",                  interp_get_main,
      METH_NOARGS, get_main_doc},
-    {"is_running",                (PyCFunction)interp_is_running,
+    {"is_running",                (PyCFunction)(void(*)(void))interp_is_running,
      METH_VARARGS | METH_KEYWORDS, is_running_doc},
-    {"run_string",                (PyCFunction)interp_run_string,
+    {"run_string",                (PyCFunction)(void(*)(void))interp_run_string,
      METH_VARARGS | METH_KEYWORDS, run_string_doc},
 
-    {"is_shareable",              (PyCFunction)object_is_shareable,
+    {"is_shareable",              (PyCFunction)(void(*)(void))object_is_shareable,
      METH_VARARGS | METH_KEYWORDS, is_shareable_doc},
 
     {"channel_create",            channel_create,
      METH_NOARGS, channel_create_doc},
-    {"channel_destroy",           (PyCFunction)channel_destroy,
+    {"channel_destroy",           (PyCFunction)(void(*)(void))channel_destroy,
      METH_VARARGS | METH_KEYWORDS, channel_destroy_doc},
     {"channel_list_all",          channel_list_all,
      METH_NOARGS, channel_list_all_doc},
-    {"channel_send",              (PyCFunction)channel_send,
+    {"channel_send",              (PyCFunction)(void(*)(void))channel_send,
      METH_VARARGS | METH_KEYWORDS, channel_send_doc},
-    {"channel_recv",              (PyCFunction)channel_recv,
+    {"channel_recv",              (PyCFunction)(void(*)(void))channel_recv,
      METH_VARARGS | METH_KEYWORDS, channel_recv_doc},
-    {"channel_close",             (PyCFunction)channel_close,
+    {"channel_close",             (PyCFunction)(void(*)(void))channel_close,
      METH_VARARGS | METH_KEYWORDS, channel_close_doc},
-    {"channel_release",           (PyCFunction)channel_release,
+    {"channel_release",           (PyCFunction)(void(*)(void))channel_release,
      METH_VARARGS | METH_KEYWORDS, channel_release_doc},
-    {"_channel_id",               (PyCFunction)channel__channel_id,
+    {"_channel_id",               (PyCFunction)(void(*)(void))channel__channel_id,
      METH_VARARGS | METH_KEYWORDS, NULL},
 
     {NULL,                        NULL}           /* sentinel */
diff --git a/Modules/atexitmodule.c b/Modules/atexitmodule.c
index afa1cfa..1d6d6e5 100644
--- a/Modules/atexitmodule.c
+++ b/Modules/atexitmodule.c
@@ -291,7 +291,7 @@ atexit_unregister(PyObject *self, PyObject *func)
 }
 
 static PyMethodDef atexit_methods[] = {
-    {"register", (PyCFunction) atexit_register, METH_VARARGS|METH_KEYWORDS,
+    {"register", (PyCFunction)(void(*)(void)) atexit_register, METH_VARARGS|METH_KEYWORDS,
         atexit_register__doc__},
     {"_clear", (PyCFunction) atexit_clear, METH_NOARGS,
         atexit_clear__doc__},
diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c
index 17bf3fa..30fe186 100644
--- a/Modules/faulthandler.c
+++ b/Modules/faulthandler.c
@@ -1175,7 +1175,7 @@ PyDoc_STRVAR(module_doc,
 
 static PyMethodDef module_methods[] = {
     {"enable",
-     (PyCFunction)faulthandler_py_enable, METH_VARARGS|METH_KEYWORDS,
+     (PyCFunction)(void(*)(void))faulthandler_py_enable, METH_VARARGS|METH_KEYWORDS,
      PyDoc_STR("enable(file=sys.stderr, all_threads=True): "
                "enable the fault handler")},
     {"disable", faulthandler_disable_py, METH_NOARGS,
@@ -1183,13 +1183,13 @@ static PyMethodDef module_methods[] = {
     {"is_enabled", faulthandler_is_enabled, METH_NOARGS,
      PyDoc_STR("is_enabled()->bool: check if the handler is enabled")},
     {"dump_traceback",
-     (PyCFunction)faulthandler_dump_traceback_py, METH_VARARGS|METH_KEYWORDS,
+     (PyCFunction)(void(*)(void))faulthandler_dump_traceback_py, METH_VARARGS|METH_KEYWORDS,
      PyDoc_STR("dump_traceback(file=sys.stderr, all_threads=True): "
                "dump the traceback of the current thread, or of all threads "
                "if all_threads is True, into file")},
 #ifdef FAULTHANDLER_LATER
     {"dump_traceback_later",
-     (PyCFunction)faulthandler_dump_traceback_later, METH_VARARGS|METH_KEYWORDS,
+     (PyCFunction)(void(*)(void))faulthandler_dump_traceback_later, METH_VARARGS|METH_KEYWORDS,
      PyDoc_STR("dump_traceback_later(timeout, repeat=False, file=sys.stderrn, exit=False):\n"
                "dump the traceback of all threads in timeout seconds,\n"
                "or each timeout seconds if repeat is True. If exit is True, "
@@ -1202,13 +1202,13 @@ static PyMethodDef module_methods[] = {
 
 #ifdef FAULTHANDLER_USER
     {"register",
-     (PyCFunction)faulthandler_register_py, METH_VARARGS|METH_KEYWORDS,
+     (PyCFunction)(void(*)(void))faulthandler_register_py, METH_VARARGS|METH_KEYWORDS,
      PyDoc_STR("register(signum, file=sys.stderr, all_threads=True, chain=False): "
                "register a handler for the signal 'signum': dump the "
                "traceback of the current thread, or of all threads if "
                "all_threads is True, into file")},
     {"unregister",
-     faulthandler_unregister_py, METH_VARARGS|METH_KEYWORDS,
+     (PyCFunction)(void(*)(void))faulthandler_unregister_py, METH_VARARGS|METH_KEYWORDS,
      PyDoc_STR("unregister(signum): unregister the handler of the signal "
                 "'signum' registered by register()")},
 #endif
diff --git a/Modules/nismodule.c b/Modules/nismodule.c
index 1a538dc..bc6796c 100644
--- a/Modules/nismodule.c
+++ b/Modules/nismodule.c
@@ -423,13 +423,13 @@ nis_maps (PyObject *self, PyObject *args, PyObject *kwdict)
 }
 
 static PyMethodDef nis_methods[] = {
-    {"match",                   (PyCFunction)nis_match,
+    {"match",                   (PyCFunction)(void(*)(void))nis_match,
                                     METH_VARARGS | METH_KEYWORDS,
                                     match__doc__},
-    {"cat",                     (PyCFunction)nis_cat,
+    {"cat",                     (PyCFunction)(void(*)(void))nis_cat,
                                     METH_VARARGS | METH_KEYWORDS,
                                     cat__doc__},
-    {"maps",                    (PyCFunction)nis_maps,
+    {"maps",                    (PyCFunction)(void(*)(void))nis_maps,
                                     METH_VARARGS | METH_KEYWORDS,
                                     maps__doc__},
     {"get_default_domain",      nis_get_default_domain,
diff --git a/Modules/parsermodule.c b/Modules/parsermodule.c
index c8fb3d2..8f88657 100644
--- a/Modules/parsermodule.c
+++ b/Modules/parsermodule.c
@@ -206,15 +206,15 @@ static PyObject* parser_st2tuple(PyST_Object *, PyObject *, PyObject *);
 #define PUBLIC_METHOD_TYPE (METH_VARARGS|METH_KEYWORDS)
 
 static PyMethodDef parser_methods[] = {
-    {"compile",         (PyCFunction)parser_compilest,  PUBLIC_METHOD_TYPE,
+    {"compile",         (PyCFunction)(void(*)(void))parser_compilest,  PUBLIC_METHOD_TYPE,
         PyDoc_STR("Compile this ST object into a code object.")},
-    {"isexpr",          (PyCFunction)parser_isexpr,     PUBLIC_METHOD_TYPE,
+    {"isexpr",          (PyCFunction)(void(*)(void))parser_isexpr,     PUBLIC_METHOD_TYPE,
         PyDoc_STR("Determines if this ST object was created from an expression.")},
-    {"issuite",         (PyCFunction)parser_issuite,    PUBLIC_METHOD_TYPE,
+    {"issuite",         (PyCFunction)(void(*)(void))parser_issuite,    PUBLIC_METHOD_TYPE,
         PyDoc_STR("Determines if this ST object was created from a suite.")},
-    {"tolist",          (PyCFunction)parser_st2list,    PUBLIC_METHOD_TYPE,
+    {"tolist",          (PyCFunction)(void(*)(void))parser_st2list,    PUBLIC_METHOD_TYPE,
         PyDoc_STR("Creates a list-tree representation of this ST.")},
-    {"totuple",         (PyCFunction)parser_st2tuple,   PUBLIC_METHOD_TYPE,
+    {"totuple",         (PyCFunction)(void(*)(void))parser_st2tuple,   PUBLIC_METHOD_TYPE,
         PyDoc_STR("Creates a tuple-tree representation of this ST.")},
     {"__sizeof__",      (PyCFunction)parser_sizeof,     METH_NOARGS,
         PyDoc_STR("Returns size in memory, in bytes.")},
@@ -1087,23 +1087,23 @@ parser__pickler(PyObject *self, PyObject *args)
  *  inheritance.
  */
 static PyMethodDef parser_functions[] =  {
-    {"compilest",      (PyCFunction)parser_compilest,  PUBLIC_METHOD_TYPE,
+    {"compilest",      (PyCFunction)(void(*)(void))parser_compilest,  PUBLIC_METHOD_TYPE,
         PyDoc_STR("Compiles an ST object into a code object.")},
-    {"expr",            (PyCFunction)parser_expr,      PUBLIC_METHOD_TYPE,
+    {"expr",            (PyCFunction)(void(*)(void))parser_expr,      PUBLIC_METHOD_TYPE,
         PyDoc_STR("Creates an ST object from an expression.")},
-    {"isexpr",          (PyCFunction)parser_isexpr,    PUBLIC_METHOD_TYPE,
+    {"isexpr",          (PyCFunction)(void(*)(void))parser_isexpr,    PUBLIC_METHOD_TYPE,
         PyDoc_STR("Determines if an ST object was created from an expression.")},
-    {"issuite",         (PyCFunction)parser_issuite,   PUBLIC_METHOD_TYPE,
+    {"issuite",         (PyCFunction)(void(*)(void))parser_issuite,   PUBLIC_METHOD_TYPE,
         PyDoc_STR("Determines if an ST object was created from a suite.")},
-    {"suite",           (PyCFunction)parser_suite,     PUBLIC_METHOD_TYPE,
+    {"suite",           (PyCFunction)(void(*)(void))parser_suite,     PUBLIC_METHOD_TYPE,
         PyDoc_STR("Creates an ST object from a suite.")},
-    {"sequence2st",     (PyCFunction)parser_tuple2st,  PUBLIC_METHOD_TYPE,
+    {"sequence2st",     (PyCFunction)(void(*)(void))parser_tuple2st,  PUBLIC_METHOD_TYPE,
         PyDoc_STR("Creates an ST object from a tree representation.")},
-    {"st2tuple",        (PyCFunction)parser_st2tuple,  PUBLIC_METHOD_TYPE,
+    {"st2tuple",        (PyCFunction)(void(*)(void))parser_st2tuple,  PUBLIC_METHOD_TYPE,
         PyDoc_STR("Creates a tuple-tree representation of an ST.")},
-    {"st2list",         (PyCFunction)parser_st2list,   PUBLIC_METHOD_TYPE,
+    {"st2list",         (PyCFunction)(void(*)(void))parser_st2list,   PUBLIC_METHOD_TYPE,
         PyDoc_STR("Creates a list-tree representation of an ST.")},
-    {"tuple2st",        (PyCFunction)parser_tuple2st,  PUBLIC_METHOD_TYPE,
+    {"tuple2st",        (PyCFunction)(void(*)(void))parser_tuple2st,  PUBLIC_METHOD_TYPE,
         PyDoc_STR("Creates an ST object from a tree representation.")},
 
     /* private stuff: support pickle module */
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 44d6009..d42e40f 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -13175,7 +13175,7 @@ static PyMethodDef posix_methods[] = {
     OS_PWRITE_METHODDEF
     OS_PWRITEV_METHODDEF
 #ifdef HAVE_SENDFILE
-    {"sendfile",        (PyCFunction)posix_sendfile, METH_VARARGS | METH_KEYWORDS,
+    {"sendfile",        (PyCFunction)(void(*)(void))posix_sendfile, METH_VARARGS | METH_KEYWORDS,
                             posix_sendfile__doc__},
 #endif
     OS_FSTAT_METHODDEF
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index 1915fd9..52ab4e9 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -1210,7 +1210,7 @@ static PyMethodDef signal_methods[] = {
     SIGNAL_SIGNAL_METHODDEF
     SIGNAL_STRSIGNAL_METHODDEF
     SIGNAL_GETSIGNAL_METHODDEF
-    {"set_wakeup_fd", (PyCFunction)signal_set_wakeup_fd, METH_VARARGS | METH_KEYWORDS, set_wakeup_fd_doc},
+    {"set_wakeup_fd", (PyCFunction)(void(*)(void))signal_set_wakeup_fd, METH_VARARGS | METH_KEYWORDS, set_wakeup_fd_doc},
     SIGNAL_SIGINTERRUPT_METHODDEF
     SIGNAL_PAUSE_METHODDEF
     SIGNAL_PTHREAD_KILL_METHODDEF
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index a47f031..04bfdaf 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -4810,11 +4810,11 @@ static PyMethodDef sock_methods[] = {
                       listen_doc},
     {"recv",              (PyCFunction)sock_recv, METH_VARARGS,
                       recv_doc},
-    {"recv_into",         (PyCFunction)sock_recv_into, METH_VARARGS | METH_KEYWORDS,
+    {"recv_into",         (PyCFunction)(void(*)(void))sock_recv_into, METH_VARARGS | METH_KEYWORDS,
                       recv_into_doc},
     {"recvfrom",          (PyCFunction)sock_recvfrom, METH_VARARGS,
                       recvfrom_doc},
-    {"recvfrom_into",  (PyCFunction)sock_recvfrom_into, METH_VARARGS | METH_KEYWORDS,
+    {"recvfrom_into",  (PyCFunction)(void(*)(void))sock_recvfrom_into, METH_VARARGS | METH_KEYWORDS,
                       recvfrom_into_doc},
     {"send",              (PyCFunction)sock_send, METH_VARARGS,
                       send_doc},
@@ -4843,7 +4843,7 @@ static PyMethodDef sock_methods[] = {
                       sendmsg_doc},
 #endif
 #ifdef HAVE_SOCKADDR_ALG
-    {"sendmsg_afalg",     (PyCFunction)sock_sendmsg_afalg, METH_VARARGS | METH_KEYWORDS,
+    {"sendmsg_afalg",     (PyCFunction)(void(*)(void))sock_sendmsg_afalg, METH_VARARGS | METH_KEYWORDS,
                       sendmsg_afalg_doc},
 #endif
     {NULL,                      NULL}           /* sentinel */
@@ -6741,7 +6741,7 @@ static PyMethodDef socket_methods[] = {
     {"inet_ntop",               socket_inet_ntop,
      METH_VARARGS, inet_ntop_doc},
 #endif
-    {"getaddrinfo",             (PyCFunction)socket_getaddrinfo,
+    {"getaddrinfo",             (PyCFunction)(void(*)(void))socket_getaddrinfo,
      METH_VARARGS | METH_KEYWORDS, getaddrinfo_doc},
     {"getnameinfo",             socket_getnameinfo,
      METH_VARARGS, getnameinfo_doc},
diff --git a/Modules/syslogmodule.c b/Modules/syslogmodule.c
index a5807dc..b2ea73b 100644
--- a/Modules/syslogmodule.c
+++ b/Modules/syslogmodule.c
@@ -238,7 +238,7 @@ syslog_log_upto(PyObject *self, PyObject *args)
 /* List of functions defined in the module */
 
 static PyMethodDef syslog_methods[] = {
-    {"openlog",         (PyCFunction) syslog_openlog,           METH_VARARGS | METH_KEYWORDS},
+    {"openlog",         (PyCFunction)(void(*)(void)) syslog_openlog,           METH_VARARGS | METH_KEYWORDS},
     {"closelog",        syslog_closelog,        METH_NOARGS},
     {"syslog",          syslog_syslog,          METH_VARARGS},
     {"setlogmask",      syslog_setlogmask,      METH_VARARGS},
diff --git a/Modules/xxsubtype.c b/Modules/xxsubtype.c
index 11242d7..d9cb4cd 100644
--- a/Modules/xxsubtype.c
+++ b/Modules/xxsubtype.c
@@ -70,10 +70,10 @@ static PyMethodDef spamlist_methods[] = {
         PyDoc_STR("setstate(state)")},
     /* These entries differ only in the flags; they are used by the tests
        in test.test_descr. */
-    {"classmeth", (PyCFunction)spamlist_specialmeth,
+    {"classmeth", (PyCFunction)(void(*)(void))spamlist_specialmeth,
         METH_VARARGS | METH_KEYWORDS | METH_CLASS,
         PyDoc_STR("classmeth(*args, **kw)")},
-    {"staticmeth", (PyCFunction)spamlist_specialmeth,
+    {"staticmeth", (PyCFunction)(void(*)(void))spamlist_specialmeth,
         METH_VARARGS | METH_KEYWORDS | METH_STATIC,
         PyDoc_STR("staticmeth(*args, **kw)")},
     {NULL,      NULL},