diff --git a/Lib/ctypes/__init__.py b/Lib/ctypes/__init__.py
index 1500896..897f51a 100644
--- a/Lib/ctypes/__init__.py
+++ b/Lib/ctypes/__init__.py
@@ -185,7 +185,7 @@
 _check_size(c_double)
 
 class c_longdouble(_SimpleCData):
-    _type_ = "D"
+    _type_ = "g"
 if sizeof(c_longdouble) == sizeof(c_double):
     c_longdouble = c_double
 
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index 24d3c2f..6dcba80 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -1113,7 +1113,7 @@
 
 */
 
-static char *SIMPLE_TYPE_CHARS = "cbBhHiIlLdfuzZqQPXOvtD";
+static char *SIMPLE_TYPE_CHARS = "cbBhHiIlLdfuzZqQPXOvtg";
 
 static PyObject *
 c_wchar_p_from_param(PyObject *type, PyObject *value)
diff --git a/Modules/_ctypes/cfield.c b/Modules/_ctypes/cfield.c
index 8857e44..03aacbd 100644
--- a/Modules/_ctypes/cfield.c
+++ b/Modules/_ctypes/cfield.c
@@ -995,7 +995,7 @@
 
 
 static PyObject *
-D_set(void *ptr, PyObject *value, Py_ssize_t size)
+g_set(void *ptr, PyObject *value, Py_ssize_t size)
 {
 	long double x;
 
@@ -1011,7 +1011,7 @@
 }
 
 static PyObject *
-D_get(void *ptr, Py_ssize_t size)
+g_get(void *ptr, Py_ssize_t size)
 {
 	long double val;
 	memcpy(&val, ptr, sizeof(long double));
@@ -1612,7 +1612,7 @@
 	{ 'B', B_set, B_get, &ffi_type_uchar},
 	{ 'c', c_set, c_get, &ffi_type_schar},
 	{ 'd', d_set, d_get, &ffi_type_double, d_set_sw, d_get_sw},
-	{ 'D', D_set, D_get, &ffi_type_longdouble},
+	{ 'g', g_set, g_get, &ffi_type_longdouble},
 	{ 'f', f_set, f_get, &ffi_type_float, f_set_sw, f_get_sw},
 	{ 'h', h_set, h_get, &ffi_type_sshort, h_set_sw, h_get_sw},
 	{ 'H', H_set, H_get, &ffi_type_ushort, H_set_sw, H_get_sw},