diff --git a/Lib/ctypes/__init__.py b/Lib/ctypes/__init__.pyindex d2e6a8bfc8..d941036719 100644--- a/Lib/ctypes/__init__.py+++ b/Lib/ctypes/__init__.py@@ -208,6 +208,7 @@ class c_longdouble(_SimpleCData): try:     class c_double_complex(_SimpleCData):         _type_ = "C"+    _check_size(c_double_complex) except AttributeError:     passdiff --git a/Modules/_struct.c b/Modules/_struct.cindex 6a68478dd4..caf4975413 100644--- a/Modules/_struct.c+++ b/Modules/_struct.c@@ -12,6 +12,9 @@ #include "pycore_long.h"          // _PyLong_AsByteArray() #include "pycore_moduleobject.h"  // _PyModule_GetState()+#ifdef Py_HAVE_C_COMPLEX+#  include "_complex.h"           // complex+#endif #include <stddef.h>               // offsetof()  /*[clinic input]@@ -80,6 +83,9 @@ typedef struct { char c; int x; } st_int; typedef struct { char c; long x; } st_long; typedef struct { char c; float x; } st_float; typedef struct { char c; double x; } st_double;+#ifdef Py_HAVE_C_COMPLEX+typedef struct { char c; double complex x; } st_double_complex;+#endif typedef struct { char c; void *x; } st_void_p; typedef struct { char c; size_t x; } st_size_t; typedef struct { char c; _Bool x; } st_bool;@@ -89,6 +95,9 @@ typedef struct { char c; _Bool x; } st_bool; #define LONG_ALIGN (sizeof(st_long) - sizeof(long)) #define FLOAT_ALIGN (sizeof(st_float) - sizeof(float)) #define DOUBLE_ALIGN (sizeof(st_double) - sizeof(double))+#ifdef Py_HAVE_C_COMPLEX+#define DOUBLE_COMPLEX_ALIGN (sizeof(st_double_complex) - sizeof(double complex))+#endif #define VOID_P_ALIGN (sizeof(st_void_p) - sizeof(void *)) #define SIZE_T_ALIGN (sizeof(st_size_t) - sizeof(size_t)) #define BOOL_ALIGN (sizeof(st_bool) - sizeof(_Bool))@@ -518,6 +527,17 @@ nu_double(_structmodulestate *state, const char *p, const formatdef *f)     return PyFloat_FromDouble(x); }+#ifdef Py_HAVE_C_COMPLEX+static PyObject *+nu_double_complex(_structmodulestate *state, const char *p, const formatdef *f)+{+    double complex x;++    memcpy(&x, p, sizeof(x));+    return PyComplex_FromDoubles(creal(x), cimag(x));+}+#endif+ static PyObject * nu_void_p(_structmodulestate *state, const char *p, const formatdef *f) {@@ -791,6 +811,24 @@ np_double(_structmodulestate *state, char *p, PyObject *v, const formatdef *f)     return 0; }+#ifdef Py_HAVE_C_COMPLEX+static int+np_double_complex(_structmodulestate *state, char *p, PyObject *v,+                  const formatdef *f)+{+    Py_complex c = PyComplex_AsCComplex(v);+    double complex x = CMPLX(c.real, c.imag);++    if (c.real == -1 && PyErr_Occurred()) {+        PyErr_SetString(state->StructError,+                        "required argument is not a complex");+        return -1;+    }+    memcpy(p, (char *)&x, sizeof(x));+    return 0;+}+#endif+ static int np_void_p(_structmodulestate *state, char *p, PyObject *v, const formatdef *f) {@@ -829,6 +867,9 @@ static const formatdef native_table[] = {     {'e',       sizeof(short),  SHORT_ALIGN,    nu_halffloat,   np_halffloat},     {'f',       sizeof(float),  FLOAT_ALIGN,    nu_float,       np_float},     {'d',       sizeof(double), DOUBLE_ALIGN,   nu_double,      np_double},+#ifdef Py_HAVE_C_COMPLEX+    {'C',       sizeof(double complex), DOUBLE_COMPLEX_ALIGN, nu_double_complex, np_double_complex},+#endif     {'P',       sizeof(void *), VOID_P_ALIGN,   nu_void_p,      np_void_p},     {0} };