diff --git a/Demo/embed/demo.c b/Demo/embed/demo.c
index 579ba07..26df355 100644
--- a/Demo/embed/demo.c
+++ b/Demo/embed/demo.c
@@ -2,11 +2,9 @@
 
 #include "Python.h"
 
-void initxyzzy(); /* Forward */
+void initxyzzy(void); /* Forward */
 
-main(argc, argv)
-	int argc;
-	char **argv;
+main(int argc, char **argv)
 {
 	/* Pass argv[0] to the Python interpreter */
 	Py_SetProgramName(argv[0]);
@@ -46,10 +44,9 @@
 
 /* A static module */
 
+/* 'self' is not used */
 static PyObject *
-xyzzy_foo(self, args)
-	PyObject *self; /* Not used */
-	PyObject *args;
+xyzzy_foo(PyObject *self, PyObjecT *args)
 {
 	if (!PyArg_ParseTuple(args, ""))
 		return NULL;
@@ -62,7 +59,7 @@
 };
 
 void
-initxyzzy()
+initxyzzy(void)
 {
 	PyImport_AddModule("xyzzy");
 	Py_InitModule("xyzzy", xyzzy_methods);
diff --git a/Demo/pysvr/pysvr.c b/Demo/pysvr/pysvr.c
index 995a7ca..d7d755c 100644
--- a/Demo/pysvr/pysvr.c
+++ b/Demo/pysvr/pysvr.c
@@ -34,7 +34,7 @@
 
 extern int optind;
 extern char *optarg;
-extern int getopt();
+extern int getopt(int, char **, char *);
 
 struct workorder {
 	int conn;
@@ -97,7 +97,7 @@
 static char usage_line[] = "usage: %s [port]\n";
 
 static void
-usage()
+usage(void)
 {
 	fprintf(stderr, usage_line, progname);
 	exit(2);
@@ -220,7 +220,7 @@
 static PyObject *the_builtins;
 
 static void
-init_python()
+init_python(void)
 {
 	if (gtstate)
 		return;
@@ -268,7 +268,7 @@
 }
 
 static void
-oprogname()
+oprogname(void)
 {
 	int save = errno;
 	fprintf(stderr, "%s: ", progname);
@@ -364,7 +364,7 @@
 }
 
 static void
-ps()
+ps(void)
 {
 	char buffer[100];
 	sprintf(buffer, "ps -l -p %d </dev/null | tail +2l\n", getpid());
diff --git a/Include/cStringIO.h b/Include/cStringIO.h
index fac5f05..8aff2e3 100644
--- a/Include/cStringIO.h
+++ b/Include/cStringIO.h
@@ -107,9 +107,7 @@
   ((O)->ob_type==PycStringIO->OutputType)
 
 static void *
-xxxPyCObject_Import(module_name, name)
-  char *module_name;
-  char *name;
+xxxPyCObject_Import(char *module_name, char *name)
 {
   PyObject *m, *c;
   void *r=NULL;
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 819fadd..4fafb8a 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -92,7 +92,7 @@
 } dictobject;
 
 PyObject *
-PyDict_New()
+PyDict_New(void)
 {
 	register dictobject *mp;
 	if (dummy == NULL) { /* Auto-initialize dummy */
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index c904710..359a987 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -554,7 +554,7 @@
     return -1;
 }
 
-const char *PyUnicode_GetDefaultEncoding()
+const char *PyUnicode_GetDefaultEncoding(void)
 {
     return unicode_default_encoding;
 }
@@ -4530,10 +4530,7 @@
 /* Helpers for PyUnicode_Format() */
 
 static PyObject *
-getnextarg(args, arglen, p_argidx)
-    PyObject *args;
-int arglen;
-int *p_argidx;
+getnextarg(PyObject *args, int arglen, int *p_argidx)
 {
     int argidx = *p_argidx;
     if (argidx < arglen) {
@@ -4555,26 +4552,13 @@
 #define F_ZERO	(1<<4)
 
 static
-#ifdef HAVE_STDARG_PROTOTYPES
 int usprintf(register Py_UNICODE *buffer, char *format, ...)
-#else
-int usprintf(va_alist) va_dcl
-#endif
 {
     register int i;
     int len;
     va_list va;
     char *charbuffer;
-#ifdef HAVE_STDARG_PROTOTYPES
     va_start(va, format);
-#else
-    Py_UNICODE *args;
-    char *format;
-	
-    va_start(va);
-    buffer = va_arg(va, Py_UNICODE *);
-    format = va_arg(va, char *);
-#endif
 
     /* First, format the string as char array, then expand to Py_UNICODE
        array. */
@@ -5121,7 +5105,7 @@
 
 /* Initialize the Unicode implementation */
 
-void _PyUnicode_Init()
+void _PyUnicode_Init(void)
 {
     /* Doublecheck the configuration... */
     if (sizeof(Py_UNICODE) != 2)
@@ -5138,7 +5122,7 @@
 /* Finalize the Unicode implementation */
 
 void
-_PyUnicode_Fini()
+_PyUnicode_Fini(void)
 {
     PyUnicodeObject *u = unicode_freelist;
 
diff --git a/PC/config.c b/PC/config.c
index d9d9187..d71b669 100644
--- a/PC/config.c
+++ b/PC/config.c
@@ -15,48 +15,48 @@
 
 #include "Python.h"
 
-extern void initarray();
+extern void initarray(void);
 #ifndef MS_WIN64
-extern void initaudioop();
-extern void initbinascii();
+extern void initaudioop(void);
+extern void initbinascii(void);
 #endif
-extern void initcmath();
-extern void initerrno();
+extern void initcmath(void);
+extern void initerrno(void);
 #ifdef WITH_CYCLE_GC
-extern void initgc();
+extern void initgc(void);
 #endif
 #ifndef MS_WIN64
-extern void initimageop();
+extern void initimageop(void);
 #endif
-extern void initmath();
-extern void initmd5();
-extern void initnew();
-extern void initnt();
-extern void initoperator();
-extern void initregex();
+extern void initmath(void);
+extern void initmd5(void);
+extern void initnew(void);
+extern void initnt(void);
+extern void initoperator(void);
+extern void initregex(void);
 #ifndef MS_WIN64
-extern void initrgbimg();
+extern void initrgbimg(void);
 #endif
-extern void initrotor();
-extern void initsignal();
-extern void initsha();
-extern void initstrop();
-extern void initstruct();
-extern void inittime();
-extern void initthread();
-extern void initcStringIO();
-extern void initcPickle();
-extern void initpcre();
+extern void initrotor(void);
+extern void initsignal(void);
+extern void initsha(void);
+extern void initstrop(void);
+extern void initstruct(void);
+extern void inittime(void);
+extern void initthread(void);
+extern void initcStringIO(void);
+extern void initcPickle(void);
+extern void initpcre(void);
 #ifdef WIN32
-extern void initmsvcrt();
-extern void init_locale();
+extern void initmsvcrt(void);
+extern void init_locale(void);
 #endif
-extern void init_codecs();
+extern void init_codecs(void);
 
 /* -- ADDMODULE MARKER 1 -- */
 
-extern void PyMarshal_Init();
-extern void initimp();
+extern void PyMarshal_Init(void);
+extern void initimp(void);
 
 struct _inittab _PyImport_Inittab[] = {
 
diff --git a/PC/example_nt/example.c b/PC/example_nt/example.c
index dd8964b..63682f1 100644
--- a/PC/example_nt/example.c
+++ b/PC/example_nt/example.c
@@ -1,8 +1,7 @@
 #include "Python.h"
 
 static PyObject *
-ex_foo(self, args)
-	PyObject *self, *args;
+ex_foo(PyObject *self, PyObject *args)
 {
 	printf("Hello, world\n");
 	Py_INCREF(Py_None);
@@ -15,7 +14,7 @@
 };
 
 void
-initexample()
+initexample(void)
 {
 	Py_InitModule("example", example_methods);
 }
diff --git a/PC/frozen_dllmain.c b/PC/frozen_dllmain.c
index 6ca4cd4..0873d8f 100644
--- a/PC/frozen_dllmain.c
+++ b/PC/frozen_dllmain.c
@@ -60,7 +60,7 @@
   Called by a frozen .EXE only, so that built-in extension
   modules are initialized correctly
 */
-void PyWinFreeze_ExeInit()
+void PyWinFreeze_ExeInit(void)
 {
 	char **modName;
 	for (modName = possibleModules;*modName;*modName++) {
@@ -73,7 +73,7 @@
   Called by a frozen .EXE only, so that built-in extension
   modules are cleaned up 
 */
-void PyWinFreeze_ExeTerm()
+void PyWinFreeze_ExeTerm(void)
 {
 	// Must go backwards
 	char **modName;
diff --git a/PC/getpathp.c b/PC/getpathp.c
index ea388f2..e4ff136 100644
--- a/PC/getpathp.c
+++ b/PC/getpathp.c
@@ -98,8 +98,7 @@
 
 
 static int
-is_sep(ch)	/* determine if "ch" is a separator character */
-	char ch;
+is_sep(char ch)	/* determine if "ch" is a separator character */
 {
 #ifdef ALTSEP
 	return ch == SEP || ch == ALTSEP;
@@ -110,8 +109,7 @@
 
 
 static void
-reduce(dir)
-	char *dir;
+reduce(char *dir)
 {
 	size_t i = strlen(dir);
 	while (i > 0 && !is_sep(dir[i]))
@@ -121,8 +119,7 @@
 	
 
 static int
-exists(filename)
-	char *filename;
+exists(char *filename)
 {
 	struct stat buf;
 	return stat(filename, &buf) == 0;
@@ -130,8 +127,7 @@
 
 
 static int
-ismodule(filename)	/* Is module -- check for .pyc/.pyo too */
-	char *filename;
+ismodule(char *filename)	/* Is module -- check for .pyc/.pyo too */
 {
 	if (exists(filename))
 		return 1;
@@ -147,9 +143,7 @@
 
 
 static void
-join(buffer, stuff)
-	char *buffer;
-	char *stuff;
+join(char *buffer, char *stuff)
 {
 	size_t n, k;
 	if (is_sep(stuff[0]))
@@ -168,8 +162,7 @@
 
 
 static int
-gotlandmark(landmark)
-	char *landmark;
+gotlandmark(char *landmark)
 {
 	int n, ok;
 
@@ -182,9 +175,7 @@
 
 
 static int
-search_for_prefix(argv0_path, landmark)
-	char *argv0_path;
-	char *landmark;
+search_for_prefix(char *argv0_path, char *landmark)
 {
 	/* Search from argv0_path, until landmark is found */
 	strcpy(prefix, argv0_path);
@@ -343,7 +334,7 @@
 #endif /* MS_WIN32 */
 
 static void
-get_progpath()
+get_progpath(void)
 {
 	extern char *Py_GetProgramName();
 	char *path = getenv("PATH");
@@ -403,7 +394,7 @@
 }
 
 static void
-calculate_path()
+calculate_path(void)
 {
 	char argv0_path[MAXPATHLEN+1];
 	char *buf;
@@ -565,7 +556,7 @@
 /* External interface */
 
 char *
-Py_GetPath()
+Py_GetPath(void)
 {
 	if (!module_search_path)
 		calculate_path();
@@ -573,7 +564,7 @@
 }
 
 char *
-Py_GetPrefix()
+Py_GetPrefix(void)
 {
 	if (!module_search_path)
 		calculate_path();
@@ -581,13 +572,13 @@
 }
 
 char *
-Py_GetExecPrefix()
+Py_GetExecPrefix(void)
 {
 	return Py_GetPrefix();
 }
 
 char *
-Py_GetProgramFullPath()
+Py_GetProgramFullPath(void)
 {
 	if (!module_search_path)
 		calculate_path();
diff --git a/PC/os2vacpp/config.c b/PC/os2vacpp/config.c
index 3b8f854..3d54e53 100644
--- a/PC/os2vacpp/config.c
+++ b/PC/os2vacpp/config.c
@@ -15,41 +15,41 @@
 
 #include "Python.h"
 
-extern void initarray();
-extern void initaudioop();
-extern void initbinascii();
-extern void initcmath();
-extern void initerrno();
-extern void initimageop();
-extern void initmath();
-extern void initmd5();
-extern void initnew();
-extern void initnt();
-extern void initos2();
-extern void initoperator();
-extern void initposix();
-extern void initregex();
-extern void initrgbimg();
-extern void initrotor();
-extern void initsignal();
-extern void initselect();
-extern void init_socket();
-extern void initsoundex();
-extern void initstrop();
-extern void initstruct();
-extern void inittime();
-extern void initthread();
-extern void initcStringIO();
-extern void initcPickle();
-extern void initpcre();
+extern void initarray(void);
+extern void initaudioop(void);
+extern void initbinascii(void);
+extern void initcmath(void);
+extern void initerrno(void);
+extern void initimageop(void);
+extern void initmath(void);
+extern void initmd5(void);
+extern void initnew(void);
+extern void initnt(void);
+extern void initos2(void);
+extern void initoperator(void);
+extern void initposix(void);
+extern void initregex(void);
+extern void initrgbimg(void);
+extern void initrotor(void);
+extern void initsignal(void);
+extern void initselect(void);
+extern void init_socket(void);
+extern void initsoundex(void);
+extern void initstrop(void);
+extern void initstruct(void);
+extern void inittime(void);
+extern void initthread(void);
+extern void initcStringIO(void);
+extern void initcPickle(void);
+extern void initpcre(void);
 #ifdef WIN32
-extern void initmsvcrt();
+extern void initmsvcrt(void);
 #endif
 
 /* -- ADDMODULE MARKER 1 -- */
 
-extern void PyMarshal_Init();
-extern void initimp();
+extern void PyMarshal_Init(void);
+extern void initimp(void);
 
 struct _inittab _PyImport_Inittab[] = {
 
diff --git a/PC/os2vacpp/getpathp.c b/PC/os2vacpp/getpathp.c
index f796851..1c78674 100644
--- a/PC/os2vacpp/getpathp.c
+++ b/PC/os2vacpp/getpathp.c
@@ -64,8 +64,7 @@
 
 
 static int
-is_sep(ch)	/* determine if "ch" is a separator character */
-	char ch;
+is_sep(char ch)	/* determine if "ch" is a separator character */
 {
 #ifdef ALTSEP
 	return ch == SEP || ch == ALTSEP;
@@ -76,8 +75,7 @@
 
 
 static void
-reduce(dir)
-	char *dir;
+reduce(char *dir)
 {
 	int i = strlen(dir);
 	while (i > 0 && !is_sep(dir[i]))
@@ -87,8 +85,7 @@
 	
 
 static int
-exists(filename)
-	char *filename;
+exists(char *filename)
 {
 	struct stat buf;
 	return stat(filename, &buf) == 0;
@@ -96,9 +93,7 @@
 
 
 static void
-join(buffer, stuff)
-	char *buffer;
-	char *stuff;
+join(char *buffer, char *stuff)
 {
 	int n, k;
 	if (is_sep(stuff[0]))
@@ -117,9 +112,7 @@
 
 
 static int
-search_for_prefix(argv0_path, landmark)
-	char *argv0_path;
-	char *landmark;
+search_for_prefix(char *argv0_path, char *landmark)
 {
 	int n;
 
@@ -247,7 +240,7 @@
 #endif /* MS_WIN32 */
 
 static void
-get_progpath()
+get_progpath(void)
 {
 	extern char *Py_GetProgramName();
 	char *path = getenv("PATH");
@@ -299,7 +292,7 @@
 }
 
 static void
-calculate_path()
+calculate_path(void)
 {
 	char argv0_path[MAXPATHLEN+1];
 	char *buf;
@@ -451,7 +444,7 @@
 /* External interface */
 
 char *
-Py_GetPath()
+Py_GetPath(void)
 {
 	if (!module_search_path)
 		calculate_path();
@@ -460,7 +453,7 @@
 }
 
 char *
-Py_GetPrefix()
+Py_GetPrefix(void)
 {
 	if (!module_search_path)
 		calculate_path();
@@ -469,7 +462,7 @@
 }
 
 char *
-Py_GetExecPrefix()
+Py_GetExecPrefix(void)
 {
 	if (!module_search_path)
 		calculate_path();
@@ -478,7 +471,7 @@
 }
 
 char *
-Py_GetProgramFullPath()
+Py_GetProgramFullPath(void)
 {
 	if (!module_search_path)
 		calculate_path();
diff --git a/PC/utils/makesrc.c b/PC/utils/makesrc.c
index 883b4d8..458bfab 100755
--- a/PC/utils/makesrc.c
+++ b/PC/utils/makesrc.c
@@ -7,7 +7,9 @@
 
 char *usage = "You must be in the \"pc\" directory.\n";
 char *list[] = {"..\\Include", "..\\Modules", "..\\Objects", "..\\Parser", "..\\Python", ".", 0};
-main()
+
+int
+main(int argc, char ** argv)
 {
   DIR *dpath;
   struct dirent *dir;
@@ -64,4 +66,4 @@
     closedir(dpath);
     }
   return 0;
-  }
+}
diff --git a/PC/winsound.c b/PC/winsound.c
index 63906c9..a9c14a6 100644
--- a/PC/winsound.c
+++ b/PC/winsound.c
@@ -140,7 +140,7 @@
 #define ADD_DEFINE(tok) add_define(dict,#tok,tok)
 
 DL_EXPORT(void)
-initwinsound()
+initwinsound(void)
 {
     PyObject *module=Py_InitModule3("winsound", sound_methods, sound_module_doc);
     PyObject *dict=PyModule_GetDict(module);
diff --git a/Tools/perfecthash/perfhash.c b/Tools/perfecthash/perfhash.c
index e7ba0c7..166b183 100644
--- a/Tools/perfecthash/perfhash.c
+++ b/Tools/perfecthash/perfhash.c
@@ -61,7 +61,7 @@
 #ifdef _MSC_VER
 _declspec(dllexport)
 #endif
-void initperfhash()
+void initperfhash(void)
 {
         PyObject *m;