diff --git a/Misc/NEWS b/Misc/NEWS
index c8a26767224..d0d00e9da8d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -45,6 +45,8 @@ Core and builtins
 Extension Modules
 -----------------
 
+- Patch #1493701: performance enhancements for struct module.
+
 - Patch #1490224: time.altzone is now set correctly on Cygwin.
 
 - Patch #1435422: zlib's compress and decompress objects now have a
diff --git a/Modules/Setup.dist b/Modules/Setup.dist
index 49c8425f47f..1b2502d35ac 100644
--- a/Modules/Setup.dist
+++ b/Modules/Setup.dist
@@ -167,7 +167,7 @@ GLHACK=-Dclear=__GLclear
 #array arraymodule.c	# array objects
 #cmath cmathmodule.c # -lm # complex math library functions
 #math mathmodule.c # -lm # math library functions, e.g. sin()
-#struct structmodule.c	# binary structure packing/unpacking
+#_struct _struct.c	# binary structure packing/unpacking
 #time timemodule.c # -lm # time operations and variables
 #operator operator.c	# operator.add() and similar goodies
 #_weakref _weakref.c	# basic weak reference support
diff --git a/Modules/structmodule.c b/Modules/structmodule.c
index 4713c0cf76b..e69de29bb2d 100644
--- a/Modules/structmodule.c
+++ b/Modules/structmodule.c
@@ -1,1293 +0,0 @@
-/* struct module -- pack values into and (out of) strings */
-
-/* New version supporting byte order, alignment and size options,
-   character strings, and unsigned numbers */
-
-#include "Python.h"
-#include <ctype.h>
-
-PyDoc_STRVAR(struct__doc__,
-"Functions to convert between Python values and C structs.\n\
-Python strings are used to hold the data representing the C struct\n\
-and also as format strings to describe the layout of data in the C struct.\n\
-\n\
-The optional first format char indicates byte order, size and alignment:\n\
- @: native order, size & alignment (default)\n\
- =: native order, std. size & alignment\n\
- <: little-endian, std. size & alignment\n\
- >: big-endian, std. size & alignment\n\
- !: same as >\n\
-\n\
-The remaining chars indicate types of args and must match exactly;\n\
-these can be preceded by a decimal repeat count:\n\
- x: pad byte (no data); c:char; b:signed byte; B:unsigned byte;\n\
- h:short; H:unsigned short; i:int; I:unsigned int;\n\
- l:long; L:unsigned long; f:float; d:double.\n\
-Special cases (preceding decimal count indicates length):\n\
- s:string (array of char); p: pascal string (with count byte).\n\
-Special case (only available in native format):\n\
- P:an integer type that is wide enough to hold a pointer.\n\
-Special case (not in native mode unless 'long long' in platform C):\n\
- q:long long; Q:unsigned long long\n\
-Whitespace between formats is ignored.\n\
-\n\
-The variable struct.error is an exception raised on errors.");
-
-
-/* Exception */
-
-static PyObject *StructError;
-
-
-/* Define various structs to figure out the alignments of types */
-
-
-typedef struct { char c; short x; } st_short;
-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;
-typedef struct { char c; void *x; } st_void_p;
-
-#define SHORT_ALIGN (sizeof(st_short) - sizeof(short))
-#define INT_ALIGN (sizeof(st_int) - sizeof(int))
-#define LONG_ALIGN (sizeof(st_long) - sizeof(long))
-#define FLOAT_ALIGN (sizeof(st_float) - sizeof(float))
-#define DOUBLE_ALIGN (sizeof(st_double) - sizeof(double))
-#define VOID_P_ALIGN (sizeof(st_void_p) - sizeof(void *))
-
-/* We can't support q and Q in native mode unless the compiler does;
-   in std mode, they're 8 bytes on all platforms. */
-#ifdef HAVE_LONG_LONG
-typedef struct { char c; PY_LONG_LONG x; } s_long_long;
-#define LONG_LONG_ALIGN (sizeof(s_long_long) - sizeof(PY_LONG_LONG))
-#endif
-
-#define STRINGIFY(x)    #x
-
-#ifdef __powerc
-#pragma options align=reset
-#endif
-
-/* Helper to get a PyLongObject by hook or by crook.  Caller should decref. */
-
-static PyObject *
-get_pylong(PyObject *v)
-{
-	PyNumberMethods *m;
-
-	assert(v != NULL);
-	if (PyInt_Check(v))
-		return PyLong_FromLong(PyInt_AS_LONG(v));
-	if (PyLong_Check(v)) {
-		Py_INCREF(v);
-		return v;
-	}
-	m = v->ob_type->tp_as_number;
-	if (m != NULL && m->nb_long != NULL) {
-		v = m->nb_long(v);
-		if (v == NULL)
-			return NULL;
-		if (PyLong_Check(v))
-			return v;
-		Py_DECREF(v);
-	}
-	PyErr_SetString(StructError,
-			"cannot convert argument to long");
-	return NULL;
-}
-
-/* Helper routine to get a Python integer and raise the appropriate error
-   if it isn't one */
-
-static int
-get_long(PyObject *v, long *p)
-{
-	long x = PyInt_AsLong(v);
-	if (x == -1 && PyErr_Occurred()) {
-		if (PyErr_ExceptionMatches(PyExc_TypeError))
-			PyErr_SetString(StructError,
-					"required argument is not an integer");
-		return -1;
-	}
-	*p = x;
-	return 0;
-}
-
-
-/* Same, but handling unsigned long */
-
-static int
-get_ulong(PyObject *v, unsigned long *p)
-{
-	if (PyLong_Check(v)) {
-		unsigned long x = PyLong_AsUnsignedLong(v);
-		if (x == (unsigned long)(-1) && PyErr_Occurred())
-			return -1;
-		*p = x;
-		return 0;
-	}
-	else {
-		return get_long(v, (long *)p);
-	}
-}
-
-#ifdef HAVE_LONG_LONG
-
-/* Same, but handling native long long. */
-
-static int
-get_longlong(PyObject *v, PY_LONG_LONG *p)
-{
-	PY_LONG_LONG x;
-
-	v = get_pylong(v);
-	if (v == NULL)
-		return -1;
-	assert(PyLong_Check(v));
-	x = PyLong_AsLongLong(v);
-	Py_DECREF(v);
-	if (x == (PY_LONG_LONG)-1 && PyErr_Occurred())
-		return -1;
-	*p = x;
-	return 0;
-}
-
-/* Same, but handling native unsigned long long. */
-
-static int
-get_ulonglong(PyObject *v, unsigned PY_LONG_LONG *p)
-{
-	unsigned PY_LONG_LONG x;
-
-	v = get_pylong(v);
-	if (v == NULL)
-		return -1;
-	assert(PyLong_Check(v));
-	x = PyLong_AsUnsignedLongLong(v);
-	Py_DECREF(v);
-	if (x == (unsigned PY_LONG_LONG)-1 && PyErr_Occurred())
-		return -1;
-	*p = x;
-	return 0;
-}
-
-#endif
-
-/* Floating point helpers */
-
-static PyObject *
-unpack_float(const char *p,  /* start of 4-byte string */
-             int le)	     /* true for little-endian, false for big-endian */
-{
-	double x;
-
-	x = _PyFloat_Unpack4((unsigned char *)p, le);
-	if (x == -1.0 && PyErr_Occurred())
-		return NULL;
-	return PyFloat_FromDouble(x);
-}
-
-static PyObject *
-unpack_double(const char *p,  /* start of 8-byte string */
-              int le)         /* true for little-endian, false for big-endian */
-{
-	double x;
-
-	x = _PyFloat_Unpack8((unsigned char *)p, le);
-	if (x == -1.0 && PyErr_Occurred())
-		return NULL;
-	return PyFloat_FromDouble(x);
-}
-
-
-/* The translation function for each format character is table driven */
-
-typedef struct _formatdef {
-	char format;
-	int size;
-	int alignment;
-	PyObject* (*unpack)(const char *,
-			    const struct _formatdef *);
-	int (*pack)(char *, PyObject *,
-		    const struct _formatdef *);
-} formatdef;
-
-/* A large number of small routines follow, with names of the form
-
-	[bln][up]_TYPE
-
-   [bln] distiguishes among big-endian, little-endian and native.
-   [pu] distiguishes between pack (to struct) and unpack (from struct).
-   TYPE is one of char, byte, ubyte, etc.
-*/
-
-/* Native mode routines. ****************************************************/
-/* NOTE:
-   In all n[up]_<type> routines handling types larger than 1 byte, there is
-   *no* guarantee that the p pointer is properly aligned for each type,
-   therefore memcpy is called.  An intermediate variable is used to
-   compensate for big-endian architectures.
-   Normally both the intermediate variable and the memcpy call will be
-   skipped by C optimisation in little-endian architectures (gcc >= 2.91
-   does this). */
-
-static PyObject *
-nu_char(const char *p, const formatdef *f)
-{
-	return PyString_FromStringAndSize(p, 1);
-}
-
-static PyObject *
-nu_byte(const char *p, const formatdef *f)
-{
-	return PyInt_FromLong((long) *(signed char *)p);
-}
-
-static PyObject *
-nu_ubyte(const char *p, const formatdef *f)
-{
-	return PyInt_FromLong((long) *(unsigned char *)p);
-}
-
-static PyObject *
-nu_short(const char *p, const formatdef *f)
-{
-	short x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyInt_FromLong((long)x);
-}
-
-static PyObject *
-nu_ushort(const char *p, const formatdef *f)
-{
-	unsigned short x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyInt_FromLong((long)x);
-}
-
-static PyObject *
-nu_int(const char *p, const formatdef *f)
-{
-	int x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyInt_FromLong((long)x);
-}
-
-static PyObject *
-nu_uint(const char *p, const formatdef *f)
-{
-	unsigned int x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyLong_FromUnsignedLong((unsigned long)x);
-}
-
-static PyObject *
-nu_long(const char *p, const formatdef *f)
-{
-	long x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyInt_FromLong(x);
-}
-
-static PyObject *
-nu_ulong(const char *p, const formatdef *f)
-{
-	unsigned long x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyLong_FromUnsignedLong(x);
-}
-
-/* Native mode doesn't support q or Q unless the platform C supports
-   long long (or, on Windows, __int64). */
-
-#ifdef HAVE_LONG_LONG
-
-static PyObject *
-nu_longlong(const char *p, const formatdef *f)
-{
-	PY_LONG_LONG x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyLong_FromLongLong(x);
-}
-
-static PyObject *
-nu_ulonglong(const char *p, const formatdef *f)
-{
-	unsigned PY_LONG_LONG x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyLong_FromUnsignedLongLong(x);
-}
-
-#endif
-
-static PyObject *
-nu_float(const char *p, const formatdef *f)
-{
-	float x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyFloat_FromDouble((double)x);
-}
-
-static PyObject *
-nu_double(const char *p, const formatdef *f)
-{
-	double x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyFloat_FromDouble(x);
-}
-
-static PyObject *
-nu_void_p(const char *p, const formatdef *f)
-{
-	void *x;
-	memcpy((char *)&x, p, sizeof x);
-	return PyLong_FromVoidPtr(x);
-}
-
-static int
-np_byte(char *p, PyObject *v, const formatdef *f)
-{
-	long x;
-	if (get_long(v, &x) < 0)
-		return -1;
-	if (x < -128 || x > 127){
-		PyErr_SetString(StructError,
-				"byte format requires -128<=number<=127");
-		return -1;
-	}
-	*p = (char)x;
-	return 0;
-}
-
-static int
-np_ubyte(char *p, PyObject *v, const formatdef *f)
-{
-	long x;
-	if (get_long(v, &x) < 0)
-		return -1;
-	if (x < 0 || x > 255){
-		PyErr_SetString(StructError,
-				"ubyte format requires 0<=number<=255");
-		return -1;
-	}
-	*p = (char)x;
-	return 0;
-}
-
-static int
-np_char(char *p, PyObject *v, const formatdef *f)
-{
-	if (!PyString_Check(v) || PyString_Size(v) != 1) {
-		PyErr_SetString(StructError,
-				"char format require string of length 1");
-		return -1;
-	}
-	*p = *PyString_AsString(v);
-	return 0;
-}
-
-static int
-np_short(char *p, PyObject *v, const formatdef *f)
-{
-	long x;
-	short y;
-	if (get_long(v, &x) < 0)
-		return -1;
-	if (x < SHRT_MIN || x > SHRT_MAX){
-		PyErr_SetString(StructError,
-				"short format requires " STRINGIFY(SHRT_MIN)
-				"<=number<=" STRINGIFY(SHRT_MAX));
-		return -1;
-	}
-	y = (short)x;
-	memcpy(p, (char *)&y, sizeof y);
-	return 0;
-}
-
-static int
-np_ushort(char *p, PyObject *v, const formatdef *f)
-{
-	long x;
-	unsigned short y;
-	if (get_long(v, &x) < 0)
-		return -1;
-	if (x < 0 || x > USHRT_MAX){
-		PyErr_SetString(StructError,
-				"short format requires 0<=number<=" STRINGIFY(USHRT_MAX));
-		return -1;
-	}
-	y = (unsigned short)x;
-	memcpy(p, (char *)&y, sizeof y);
-	return 0;
-}
-
-static int
-np_int(char *p, PyObject *v, const formatdef *f)
-{
-	long x;
-	int y;
-	if (get_long(v, &x) < 0)
-		return -1;
-	y = (int)x;
-	memcpy(p, (char *)&y, sizeof y);
-	return 0;
-}
-
-static int
-np_uint(char *p, PyObject *v, const formatdef *f)
-{
-	unsigned long x;
-	unsigned int y;
-	if (get_ulong(v, &x) < 0)
-		return -1;
-	y = (unsigned int)x;
-	memcpy(p, (char *)&y, sizeof y);
-	return 0;
-}
-
-static int
-np_long(char *p, PyObject *v, const formatdef *f)
-{
-	long x;
-	if (get_long(v, &x) < 0)
-		return -1;
-	memcpy(p, (char *)&x, sizeof x);
-	return 0;
-}
-
-static int
-np_ulong(char *p, PyObject *v, const formatdef *f)
-{
-	unsigned long x;
-	if (get_ulong(v, &x) < 0)
-		return -1;
-	memcpy(p, (char *)&x, sizeof x);
-	return 0;
-}
-
-#ifdef HAVE_LONG_LONG
-
-static int
-np_longlong(char *p, PyObject *v, const formatdef *f)
-{
-	PY_LONG_LONG x;
-	if (get_longlong(v, &x) < 0)
-		return -1;
-	memcpy(p, (char *)&x, sizeof x);
-	return 0;
-}
-
-static int
-np_ulonglong(char *p, PyObject *v, const formatdef *f)
-{
-	unsigned PY_LONG_LONG x;
-	if (get_ulonglong(v, &x) < 0)
-		return -1;
-	memcpy(p, (char *)&x, sizeof x);
-	return 0;
-}
-#endif
-
-static int
-np_float(char *p, PyObject *v, const formatdef *f)
-{
-	float x = (float)PyFloat_AsDouble(v);
-	if (x == -1 && PyErr_Occurred()) {
-		PyErr_SetString(StructError,
-				"required argument is not a float");
-		return -1;
-	}
-	memcpy(p, (char *)&x, sizeof x);
-	return 0;
-}
-
-static int
-np_double(char *p, PyObject *v, const formatdef *f)
-{
-	double x = PyFloat_AsDouble(v);
-	if (x == -1 && PyErr_Occurred()) {
-		PyErr_SetString(StructError,
-				"required argument is not a float");
-		return -1;
-	}
-	memcpy(p, (char *)&x, sizeof(double));
-	return 0;
-}
-
-static int
-np_void_p(char *p, PyObject *v, const formatdef *f)
-{
-	void *x;
-
-	v = get_pylong(v);
-	if (v == NULL)
-		return -1;
-	assert(PyLong_Check(v));
-	x = PyLong_AsVoidPtr(v);
-	Py_DECREF(v);
-	if (x == NULL && PyErr_Occurred())
-		return -1;
-	memcpy(p, (char *)&x, sizeof x);
-	return 0;
-}
-
-static formatdef native_table[] = {
-	{'x',	sizeof(char),	0,		NULL},
-	{'b',	sizeof(char),	0,		nu_byte,	np_byte},
-	{'B',	sizeof(char),	0,		nu_ubyte,	np_ubyte},
-	{'c',	sizeof(char),	0,		nu_char,	np_char},
-	{'s',	sizeof(char),	0,		NULL},
-	{'p',	sizeof(char),	0,		NULL},
-	{'h',	sizeof(short),	SHORT_ALIGN,	nu_short,	np_short},
-	{'H',	sizeof(short),	SHORT_ALIGN,	nu_ushort,	np_ushort},
-	{'i',	sizeof(int),	INT_ALIGN,	nu_int,		np_int},
-	{'I',	sizeof(int),	INT_ALIGN,	nu_uint,	np_uint},
-	{'l',	sizeof(long),	LONG_ALIGN,	nu_long,	np_long},
-	{'L',	sizeof(long),	LONG_ALIGN,	nu_ulong,	np_ulong},
-	{'f',	sizeof(float),	FLOAT_ALIGN,	nu_float,	np_float},
-	{'d',	sizeof(double),	DOUBLE_ALIGN,	nu_double,	np_double},
-	{'P',	sizeof(void *),	VOID_P_ALIGN,	nu_void_p,	np_void_p},
-#ifdef HAVE_LONG_LONG
-	{'q',	sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_longlong, np_longlong},
-	{'Q',	sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_ulonglong,np_ulonglong},
-#endif
-	{0}
-};
-
-/* Big-endian routines. *****************************************************/
-
-static PyObject *
-bu_int(const char *p, const formatdef *f)
-{
-	long x = 0;
-	int i = f->size;
-	do {
-		x = (x<<8) | (*p++ & 0xFF);
-	} while (--i > 0);
-	/* Extend the sign bit. */
-	if (SIZEOF_LONG > f->size)
-		x |= -(x & (1L << (8*f->size - 1)));
-	return PyInt_FromLong(x);
-}
-
-static PyObject *
-bu_uint(const char *p, const formatdef *f)
-{
-	unsigned long x = 0;
-	int i = f->size;
-	do {
-		x = (x<<8) | (*p++ & 0xFF);
-	} while (--i > 0);
-	if (f->size >= 4)
-		return PyLong_FromUnsignedLong(x);
-	else
-		return PyInt_FromLong((long)x);
-}
-
-static PyObject *
-bu_longlong(const char *p, const formatdef *f)
-{
-	return _PyLong_FromByteArray((const unsigned char *)p,
-				      8,
-				      0, /* little-endian */
-				      1  /* signed */);
-}
-
-static PyObject *
-bu_ulonglong(const char *p, const formatdef *f)
-{
-	return _PyLong_FromByteArray((const unsigned char *)p,
-				      8,
-				      0, /* little-endian */
-				      0  /* signed */);
-}
-
-static PyObject *
-bu_float(const char *p, const formatdef *f)
-{
-	return unpack_float(p, 0);
-}
-
-static PyObject *
-bu_double(const char *p, const formatdef *f)
-{
-	return unpack_double(p, 0);
-}
-
-static int
-bp_int(char *p, PyObject *v, const formatdef *f)
-{
-	long x;
-	int i;
-	if (get_long(v, &x) < 0)
-		return -1;
-	i = f->size;
-	do {
-		p[--i] = (char)x;
-		x >>= 8;
-	} while (i > 0);
-	return 0;
-}
-
-static int
-bp_uint(char *p, PyObject *v, const formatdef *f)
-{
-	unsigned long x;
-	int i;
-	if (get_ulong(v, &x) < 0)
-		return -1;
-	i = f->size;
-	do {
-		p[--i] = (char)x;
-		x >>= 8;
-	} while (i > 0);
-	return 0;
-}
-
-static int
-bp_longlong(char *p, PyObject *v, const formatdef *f)
-{
-	int res;
-	v = get_pylong(v);
-	if (v == NULL)
-		return -1;
-	res = _PyLong_AsByteArray((PyLongObject *)v,
-			   	  (unsigned char *)p,
-				  8,
-				  0, /* little_endian */
-				  1  /* signed */);
-	Py_DECREF(v);
-	return res;
-}
-
-static int
-bp_ulonglong(char *p, PyObject *v, const formatdef *f)
-{
-	int res;
-	v = get_pylong(v);
-	if (v == NULL)
-		return -1;
-	res = _PyLong_AsByteArray((PyLongObject *)v,
-			   	  (unsigned char *)p,
-				  8,
-				  0, /* little_endian */
-				  0  /* signed */);
-	Py_DECREF(v);
-	return res;
-}
-
-static int
-bp_float(char *p, PyObject *v, const formatdef *f)
-{
-	double x = PyFloat_AsDouble(v);
-	if (x == -1 && PyErr_Occurred()) {
-		PyErr_SetString(StructError,
-				"required argument is not a float");
-		return -1;
-	}
-	return _PyFloat_Pack4(x, (unsigned char *)p, 0);
-}
-
-static int
-bp_double(char *p, PyObject *v, const formatdef *f)
-{
-	double x = PyFloat_AsDouble(v);
-	if (x == -1 && PyErr_Occurred()) {
-		PyErr_SetString(StructError,
-				"required argument is not a float");
-		return -1;
-	}
-	return _PyFloat_Pack8(x, (unsigned char *)p, 0);
-}
-
-static formatdef bigendian_table[] = {
-	{'x',	1,		0,		NULL},
-	{'b',	1,		0,		bu_int,		bp_int},
-	{'B',	1,		0,		bu_uint,	bp_int},
-	{'c',	1,		0,		nu_char,	np_char},
-	{'s',	1,		0,		NULL},
-	{'p',	1,		0,		NULL},
-	{'h',	2,		0,		bu_int,		bp_int},
-	{'H',	2,		0,		bu_uint,	bp_uint},
-	{'i',	4,		0,		bu_int,		bp_int},
-	{'I',	4,		0,		bu_uint,	bp_uint},
-	{'l',	4,		0,		bu_int,		bp_int},
-	{'L',	4,		0,		bu_uint,	bp_uint},
-	{'q',	8,		0,		bu_longlong,	bp_longlong},
-	{'Q',	8,		0,		bu_ulonglong,	bp_ulonglong},
-	{'f',	4,		0,		bu_float,	bp_float},
-	{'d',	8,		0,		bu_double,	bp_double},
-	{0}
-};
-
-/* Little-endian routines. *****************************************************/
-
-static PyObject *
-lu_int(const char *p, const formatdef *f)
-{
-	long x = 0;
-	int i = f->size;
-	do {
-		x = (x<<8) | (p[--i] & 0xFF);
-	} while (i > 0);
-	/* Extend the sign bit. */
-	if (SIZEOF_LONG > f->size)
-		x |= -(x & (1L << (8*f->size - 1)));
-	return PyInt_FromLong(x);
-}
-
-static PyObject *
-lu_uint(const char *p, const formatdef *f)
-{
-	unsigned long x = 0;
-	int i = f->size;
-	do {
-		x = (x<<8) | (p[--i] & 0xFF);
-	} while (i > 0);
-	if (f->size >= 4)
-		return PyLong_FromUnsignedLong(x);
-	else
-		return PyInt_FromLong((long)x);
-}
-
-static PyObject *
-lu_longlong(const char *p, const formatdef *f)
-{
-	return _PyLong_FromByteArray((const unsigned char *)p,
-				      8,
-				      1, /* little-endian */
-				      1  /* signed */);
-}
-
-static PyObject *
-lu_ulonglong(const char *p, const formatdef *f)
-{
-	return _PyLong_FromByteArray((const unsigned char *)p,
-				      8,
-				      1, /* little-endian */
-				      0  /* signed */);
-}
-
-static PyObject *
-lu_float(const char *p, const formatdef *f)
-{
-	return unpack_float(p, 1);
-}
-
-static PyObject *
-lu_double(const char *p, const formatdef *f)
-{
-	return unpack_double(p, 1);
-}
-
-static int
-lp_int(char *p, PyObject *v, const formatdef *f)
-{
-	long x;
-	int i;
-	if (get_long(v, &x) < 0)
-		return -1;
-	i = f->size;
-	do {
-		*p++ = (char)x;
-		x >>= 8;
-	} while (--i > 0);
-	return 0;
-}
-
-static int
-lp_uint(char *p, PyObject *v, const formatdef *f)
-{
-	unsigned long x;
-	int i;
-	if (get_ulong(v, &x) < 0)
-		return -1;
-	i = f->size;
-	do {
-		*p++ = (char)x;
-		x >>= 8;
-	} while (--i > 0);
-	return 0;
-}
-
-static int
-lp_longlong(char *p, PyObject *v, const formatdef *f)
-{
-	int res;
-	v = get_pylong(v);
-	if (v == NULL)
-		return -1;
-	res = _PyLong_AsByteArray((PyLongObject*)v,
-			   	  (unsigned char *)p,
-				  8,
-				  1, /* little_endian */
-				  1  /* signed */);
-	Py_DECREF(v);
-	return res;
-}
-
-static int
-lp_ulonglong(char *p, PyObject *v, const formatdef *f)
-{
-	int res;
-	v = get_pylong(v);
-	if (v == NULL)
-		return -1;
-	res = _PyLong_AsByteArray((PyLongObject*)v,
-			   	  (unsigned char *)p,
-				  8,
-				  1, /* little_endian */
-				  0  /* signed */);
-	Py_DECREF(v);
-	return res;
-}
-
-static int
-lp_float(char *p, PyObject *v, const formatdef *f)
-{
-	double x = PyFloat_AsDouble(v);
-	if (x == -1 && PyErr_Occurred()) {
-		PyErr_SetString(StructError,
-				"required argument is not a float");
-		return -1;
-	}
-	return _PyFloat_Pack4(x, (unsigned char *)p, 1);
-}
-
-static int
-lp_double(char *p, PyObject *v, const formatdef *f)
-{
-	double x = PyFloat_AsDouble(v);
-	if (x == -1 && PyErr_Occurred()) {
-		PyErr_SetString(StructError,
-				"required argument is not a float");
-		return -1;
-	}
-	return _PyFloat_Pack8(x, (unsigned char *)p, 1);
-}
-
-static formatdef lilendian_table[] = {
-	{'x',	1,		0,		NULL},
-	{'b',	1,		0,		lu_int,		lp_int},
-	{'B',	1,		0,		lu_uint,	lp_int},
-	{'c',	1,		0,		nu_char,	np_char},
-	{'s',	1,		0,		NULL},
-	{'p',	1,		0,		NULL},
-	{'h',	2,		0,		lu_int,		lp_int},
-	{'H',	2,		0,		lu_uint,	lp_uint},
-	{'i',	4,		0,		lu_int,		lp_int},
-	{'I',	4,		0,		lu_uint,	lp_uint},
-	{'l',	4,		0,		lu_int,		lp_int},
-	{'L',	4,		0,		lu_uint,	lp_uint},
-	{'q',	8,		0,		lu_longlong,	lp_longlong},
-	{'Q',	8,		0,		lu_ulonglong,	lp_ulonglong},
-	{'f',	4,		0,		lu_float,	lp_float},
-	{'d',	8,		0,		lu_double,	lp_double},
-	{0}
-};
-
-
-static const formatdef *
-whichtable(char **pfmt)
-{
-	const char *fmt = (*pfmt)++; /* May be backed out of later */
-	switch (*fmt) {
-	case '<':
-		return lilendian_table;
-	case '>':
-	case '!': /* Network byte order is big-endian */
-		return bigendian_table;
-	case '=': { /* Host byte order -- different from native in aligment! */
-		int n = 1;
-		char *p = (char *) &n;
-		if (*p == 1)
-			return lilendian_table;
-		else
-			return bigendian_table;
-	}
-	default:
-		--*pfmt; /* Back out of pointer increment */
-		/* Fall through */
-	case '@':
-		return native_table;
-	}
-}
-
-
-/* Get the table entry for a format code */
-
-static const formatdef *
-getentry(int c, const formatdef *f)
-{
-	for (; f->format != '\0'; f++) {
-		if (f->format == c) {
-			return f;
-		}
-	}
-	PyErr_SetString(StructError, "bad char in struct format");
-	return NULL;
-}
-
-
-/* Align a size according to a format code */
-
-static int
-align(int size, int c, const formatdef *e)
-{
-	if (e->format == c) {
-		if (e->alignment) {
-			size = ((size + e->alignment - 1)
-				/ e->alignment)
-				* e->alignment;
-		}
-	}
-	return size;
-}
-
-
-/* calculate the size of a format string */
-
-static int
-calcsize(const char *fmt, const formatdef *f)
-{
-	const formatdef *e;
-	const char *s;
-	char c;
-	int size,  num, itemsize, x;
-
-	s = fmt;
-	size = 0;
-	while ((c = *s++) != '\0') {
-		if (isspace(Py_CHARMASK(c)))
-			continue;
-		if ('0' <= c && c <= '9') {
-			num = c - '0';
-			while ('0' <= (c = *s++) && c <= '9') {
-				x = num*10 + (c - '0');
-				if (x/10 != num) {
-					PyErr_SetString(
-						StructError,
-						"overflow in item count");
-					return -1;
-				}
-				num = x;
-			}
-			if (c == '\0')
-				break;
-		}
-		else
-			num = 1;
-
-		e = getentry(c, f);
-		if (e == NULL)
-			return -1;
-		itemsize = e->size;
-		size = align(size, c, e);
-		x = num * itemsize;
-		size += x;
-		if (x/itemsize != num || size < 0) {
-			PyErr_SetString(StructError,
-					"total struct size too long");
-			return -1;
-		}
-	}
-
-	return size;
-}
-
-
-PyDoc_STRVAR(calcsize__doc__,
-"calcsize(fmt) -> int\n\
-Return size of C struct described by format string fmt.\n\
-See struct.__doc__ for more on format strings.");
-
-static PyObject *
-struct_calcsize(PyObject *self, PyObject *args)
-{
-	char *fmt;
-	const formatdef *f;
-	int size;
-
-	if (!PyArg_ParseTuple(args, "s:calcsize", &fmt))
-		return NULL;
-	f = whichtable(&fmt);
-	size = calcsize(fmt, f);
-	if (size < 0)
-		return NULL;
-	return PyInt_FromLong((long)size);
-}
-
-
-PyDoc_STRVAR(pack__doc__,
-"pack(fmt, v1, v2, ...) -> string\n\
-Return string containing values v1, v2, ... packed according to fmt.\n\
-See struct.__doc__ for more on format strings.");
-
-static PyObject *
-struct_pack(PyObject *self, PyObject *args)
-{
-	const formatdef *f, *e;
-	PyObject *format, *result, *v;
-	char *fmt;
-	int size, num;
-	Py_ssize_t i, n;
-	char *s, *res, *restart, *nres;
-	char c;
-
-	if (args == NULL || !PyTuple_Check(args) ||
-	    (n = PyTuple_Size(args)) < 1)
-	{
-		PyErr_SetString(PyExc_TypeError,
-			"struct.pack requires at least one argument");
-		return NULL;
-	}
-	format = PyTuple_GetItem(args, 0);
-	fmt = PyString_AsString(format);
-	if (!fmt)
-		return NULL;
-	f = whichtable(&fmt);
-	size = calcsize(fmt, f);
-	if (size < 0)
-		return NULL;
-	result = PyString_FromStringAndSize((char *)NULL, size);
-	if (result == NULL)
-		return NULL;
-
-	s = fmt;
-	i = 1;
-	res = restart = PyString_AsString(result);
-
-	while ((c = *s++) != '\0') {
-		if (isspace(Py_CHARMASK(c)))
-			continue;
-		if ('0' <= c && c <= '9') {
-			num = c - '0';
-			while ('0' <= (c = *s++) && c <= '9')
-			       num = num*10 + (c - '0');
-			if (c == '\0')
-				break;
-		}
-		else
-			num = 1;
-
-		e = getentry(c, f);
-		if (e == NULL)
-			goto fail;
-		nres = restart + align((int)(res-restart), c, e);
-		/* Fill padd bytes with zeros */
-		while (res < nres)
-			*res++ = '\0';
-		if (num == 0 && c != 's')
-			continue;
-		do {
-			if (c == 'x') {
-				/* doesn't consume arguments */
-				memset(res, '\0', num);
-				res += num;
-				break;
-			}
-			if (i >= n) {
-				PyErr_SetString(StructError,
-					"insufficient arguments to pack");
-				goto fail;
-				}
-			v = PyTuple_GetItem(args, i++);
-			if (v == NULL)
-				goto fail;
-			if (c == 's') {
-				/* num is string size, not repeat count */
-				Py_ssize_t n;
-				if (!PyString_Check(v)) {
-					PyErr_SetString(StructError,
-					  "argument for 's' must be a string");
-					goto fail;
-				}
-				n = PyString_Size(v);
-				if (n > num)
-					n = num;
-				if (n > 0)
-					memcpy(res, PyString_AsString(v), n);
-				if (n < num)
-					memset(res+n, '\0', num-n);
-				res += num;
-				break;
-			}
-			else if (c == 'p') {
-				/* num is string size + 1,
-				   to fit in the count byte */
-				Py_ssize_t n;
-				num--; /* now num is max string size */
-				if (!PyString_Check(v)) {
-					PyErr_SetString(StructError,
-					  "argument for 'p' must be a string");
-					goto fail;
-				}
-				n = PyString_Size(v);
-				if (n > num)
-					n = num;
-				if (n > 0)
-					memcpy(res+1, PyString_AsString(v), n);
-				if (n < num)
-					/* no real need, just to be nice */
-					memset(res+1+n, '\0', num-n);
-				if (n > 255)
-					n = 255;
-				/* store the length byte */
-				*res++ = Py_SAFE_DOWNCAST(n, Py_ssize_t, unsigned char);
-				res += num;
-				break;
-			}
-			else {
-				if (e->pack(res, v, e) < 0)
-					goto fail;
-				res += e->size;
-			}
-		} while (--num > 0);
-	}
-
-	if (i < n) {
-		PyErr_SetString(StructError,
-				"too many arguments for pack format");
-		goto fail;
-	}
-
-	return result;
-
- fail:
-	Py_DECREF(result);
-	return NULL;
-}
-
-
-PyDoc_STRVAR(unpack__doc__,
-"unpack(fmt, string) -> (v1, v2, ...)\n\
-Unpack the string, containing packed C structure data, according\n\
-to fmt.  Requires len(string)==calcsize(fmt).\n\
-See struct.__doc__ for more on format strings.");
-
-static PyObject *
-struct_unpack(PyObject *self, PyObject *args)
-{
-	const formatdef *f, *e;
-	char *str, *start, *fmt, *s;
-	char c;
-	int len, size, num;
-	PyObject *res, *v;
-
-	if (!PyArg_ParseTuple(args, "ss#:unpack", &fmt, &start, &len))
-		return NULL;
-	f = whichtable(&fmt);
-	size = calcsize(fmt, f);
-	if (size < 0)
-		return NULL;
-	if (size != len) {
-		PyErr_SetString(StructError,
-				"unpack str size does not match format");
-		return NULL;
-	}
-	res = PyList_New(0);
-	if (res == NULL)
-		return NULL;
-	str = start;
-	s = fmt;
-	while ((c = *s++) != '\0') {
-		if (isspace(Py_CHARMASK(c)))
-			continue;
-		if ('0' <= c && c <= '9') {
-			num = c - '0';
-			while ('0' <= (c = *s++) && c <= '9')
-			       num = num*10 + (c - '0');
-			if (c == '\0')
-				break;
-		}
-		else
-			num = 1;
-
-		e = getentry(c, f);
-		if (e == NULL)
-			goto fail;
-		str = start + align((int)(str-start), c, e);
-		if (num == 0 && c != 's')
-			continue;
-
-		do {
-			if (c == 'x') {
-				str += num;
-				break;
-			}
-			if (c == 's') {
-				/* num is string size, not repeat count */
-				v = PyString_FromStringAndSize(str, num);
-				if (v == NULL)
-					goto fail;
-				str += num;
-				num = 0;
-			}
-			else if (c == 'p') {
-				/* num is string buffer size,
-				   not repeat count */
-				int n = *(unsigned char*)str;
-				/* first byte (unsigned) is string size */
-				if (n >= num)
-					n = num-1;
-				v = PyString_FromStringAndSize(str+1, n);
-				if (v == NULL)
-					goto fail;
-				str += num;
-				num = 0;
-			}
-			else {
-				v = e->unpack(str, e);
-				if (v == NULL)
-					goto fail;
-				str += e->size;
-			}
-			if (v == NULL || PyList_Append(res, v) < 0)
-				goto fail;
-			Py_DECREF(v);
-		} while (--num > 0);
-	}
-
-	v = PyList_AsTuple(res);
-	Py_DECREF(res);
-	return v;
-
- fail:
-	Py_DECREF(res);
-	return NULL;
-}
-
-
-/* List of functions */
-
-static PyMethodDef struct_methods[] = {
-	{"calcsize",	struct_calcsize,	METH_VARARGS, calcsize__doc__},
-	{"pack",	struct_pack,		METH_VARARGS, pack__doc__},
-	{"unpack",	struct_unpack,		METH_VARARGS, unpack__doc__},
-	{NULL,		NULL}		/* sentinel */
-};
-
-
-/* Module initialization */
-
-PyMODINIT_FUNC
-initstruct(void)
-{
-	PyObject *m;
-
-	/* Create the module and add the functions */
-	m = Py_InitModule4("struct", struct_methods, struct__doc__,
-			   (PyObject*)NULL, PYTHON_API_VERSION);
-	if (m == NULL)
-		return;
-
-	/* Add some symbolic constants to the module */
-	if (StructError == NULL) {
-		StructError = PyErr_NewException("struct.error", NULL, NULL);
-		if (StructError == NULL)
-			return;
-	}
-	Py_INCREF(StructError);
-	PyModule_AddObject(m, "error", StructError);
-}
diff --git a/setup.py b/setup.py
index a0996dcad8c..8567fc70efd 100644
--- a/setup.py
+++ b/setup.py
@@ -1444,7 +1444,7 @@ def main():
                       'install_lib':PyBuildInstallLib},
           # The struct module is defined here, because build_ext won't be
           # called unless there's at least one extension module defined.
-          ext_modules=[Extension('struct', ['structmodule.c'])],
+          ext_modules=[Extension('_struct', ['_struct.c'])],
 
           # Scripts to install
           scripts = ['Tools/scripts/pydoc', 'Tools/scripts/idle',