diff --git a/dlls/advpack/tests/files.c b/dlls/advpack/tests/files.c
index 960e4e7ff74..57117188af0 100644
--- a/dlls/advpack/tests/files.c
+++ b/dlls/advpack/tests/files.c
@@ -35,7 +35,7 @@ static HRESULT (WINAPI *pAdvInstallFile)(HWND,LPCSTR,LPCSTR,LPCSTR,LPCSTR,DWORD,
 
 CHAR CURR_DIR[MAX_PATH];
 
-static void init_function_pointers()
+static void init_function_pointers(void)
 {
     hAdvPack = LoadLibraryA("advpack.dll");
 
@@ -59,7 +59,7 @@ static void createTestFile(const CHAR *name)
     CloseHandle(file);
 }
 
-static void create_test_files()
+static void create_test_files(void)
 {
     int len;
 
@@ -77,7 +77,7 @@ static void create_test_files()
     CreateDirectoryA("dest", NULL);
 }
 
-static void delete_test_files()
+static void delete_test_files(void)
 {
     DeleteFileA("a.txt");
     DeleteFileA("b.txt");
@@ -262,7 +262,7 @@ static void set_cab_parameters(PCCAB pCabParams)
     lstrcpyA(pCabParams->szCab, "extract.cab");
 }
 
-static void create_cab_file()
+static void create_cab_file(void)
 {
     CCAB cabParams;
     HFCI hfci;
@@ -289,7 +289,7 @@ static void create_cab_file()
     ok(res, "Failed to destroy the cabinet\n");
 }
 
-static void test_ExtractFiles()
+static void test_ExtractFiles(void)
 {
     HRESULT hr;
     char destFolder[MAX_PATH];
diff --git a/dlls/cabinet/tests/extract.c b/dlls/cabinet/tests/extract.c
index f9ea07ac857..86c55e70524 100644
--- a/dlls/cabinet/tests/extract.c
+++ b/dlls/cabinet/tests/extract.c
@@ -58,7 +58,7 @@ static HRESULT (WINAPI *pExtract)(EXTRACTDEST*, LPCSTR);
 
 CHAR CURR_DIR[MAX_PATH];
 
-static void init_function_pointers()
+static void init_function_pointers(void)
 {
     hCabinet = LoadLibraryA("cabinet.dll");
 
@@ -81,7 +81,7 @@ static void createTestFile(const CHAR *name)
     CloseHandle(file);
 }
 
-static void create_test_files()
+static void create_test_files(void)
 {
     int len;
 
@@ -99,7 +99,7 @@ static void create_test_files()
     CreateDirectoryA("dest", NULL);
 }
 
-static void delete_test_files()
+static void delete_test_files(void)
 {
     DeleteFileA("a.txt");
     DeleteFileA("b.txt");
@@ -283,7 +283,7 @@ static void set_cab_parameters(PCCAB pCabParams)
     lstrcpyA(pCabParams->szCab, "extract.cab");
 }
 
-static void create_cab_file()
+static void create_cab_file(void)
 {
     CCAB cabParams;
     HFCI hfci;
@@ -310,7 +310,7 @@ static void create_cab_file()
     ok(res, "Failed to destroy the cabinet\n");
 }
 
-static void test_Extract()
+static void test_Extract(void)
 {
     EXTRACTDEST extractDest;
     HRESULT res;
diff --git a/dlls/comctl32/tests/comboex.c b/dlls/comctl32/tests/comboex.c
index d724482b937..8a109a53427 100644
--- a/dlls/comctl32/tests/comboex.c
+++ b/dlls/comctl32/tests/comboex.c
@@ -68,7 +68,7 @@ static LONG getItem(HWND cbex, int idx, COMBOBOXEXITEM *cbItem) {
     return (LONG)SendMessage(cbex, CBEM_GETITEM, 0, (LPARAM)cbItem);
 }
 
-static void test_comboboxex() {
+static void test_comboboxex(void) {
     HWND myHwnd = 0;
     LONG res = -1;
     COMBOBOXEXITEM cbexItem;
diff --git a/dlls/gdi/region.c b/dlls/gdi/region.c
index 27d79147187..e07ea3aa5e8 100644
--- a/dlls/gdi/region.c
+++ b/dlls/gdi/region.c
@@ -439,8 +439,6 @@ typedef struct _ScanLineListBlock {
    } \
 }
 
-typedef void (*voidProcp)();
-
 /* Note the parameter order is different from the X11 equivalents */
 
 static void REGION_CopyRegion(WINEREGION *d, WINEREGION *s);
@@ -1563,9 +1561,9 @@ static void REGION_RegionOp(
 	    WINEREGION *newReg, /* Place to store result */
 	    WINEREGION *reg1,   /* First region in operation */
             WINEREGION *reg2,   /* 2nd region in operation */
-	    void (*overlapFunc)(),     /* Function to call for over-lapping bands */
-	    void (*nonOverlap1Func)(), /* Function to call for non-overlapping bands in region 1 */
-	    void (*nonOverlap2Func)()  /* Function to call for non-overlapping bands in region 2 */
+	    void (*overlapFunc)(WINEREGION*, RECT*, RECT*, RECT*, RECT*, INT, INT),     /* Function to call for over-lapping bands */
+	    void (*nonOverlap1Func)(WINEREGION*, RECT*, RECT*, INT, INT), /* Function to call for non-overlapping bands in region 1 */
+	    void (*nonOverlap2Func)(WINEREGION*, RECT*, RECT*, INT, INT)  /* Function to call for non-overlapping bands in region 2 */
 ) {
     RECT *r1;                         /* Pointer into first region */
     RECT *r2;                         /* Pointer into 2d region */
@@ -1909,8 +1907,7 @@ static void REGION_IntersectRegion(WINEREGION *newReg, WINEREGION *reg1,
 	(!EXTENTCHECK(&reg1->extents, &reg2->extents)))
 	newReg->numRects = 0;
     else
-	REGION_RegionOp (newReg, reg1, reg2,
-	 (voidProcp) REGION_IntersectO, (voidProcp) NULL, (voidProcp) NULL);
+	REGION_RegionOp (newReg, reg1, reg2, REGION_IntersectO, NULL, NULL);
 
     /*
      * Can't alter newReg's extents before we call miRegionOp because
@@ -2088,8 +2085,7 @@ static void REGION_UnionRegion(WINEREGION *newReg, WINEREGION *reg1,
 	return;
     }
 
-    REGION_RegionOp (newReg, reg1, reg2, (voidProcp) REGION_UnionO,
-		(voidProcp) REGION_UnionNonO, (voidProcp) REGION_UnionNonO);
+    REGION_RegionOp (newReg, reg1, reg2, REGION_UnionO, REGION_UnionNonO, REGION_UnionNonO);
 
     newReg->extents.left = min(reg1->extents.left, reg2->extents.left);
     newReg->extents.top = min(reg1->extents.top, reg2->extents.top);
@@ -2288,8 +2284,7 @@ static void REGION_SubtractRegion(WINEREGION *regD, WINEREGION *regM,
 	return;
     }
 
-    REGION_RegionOp (regD, regM, regS, (voidProcp) REGION_SubtractO,
-		(voidProcp) REGION_SubtractNonO1, (voidProcp) NULL);
+    REGION_RegionOp (regD, regM, regS, REGION_SubtractO, REGION_SubtractNonO1, NULL);
 
     /*
      * Can't alter newReg's extents before we call miRegionOp because
diff --git a/dlls/mshtml/nsembed.c b/dlls/mshtml/nsembed.c
index c17319a564c..34f4a464763 100644
--- a/dlls/mshtml/nsembed.c
+++ b/dlls/mshtml/nsembed.c
@@ -241,7 +241,7 @@ static void set_profile(void)
     nsIProfile_Release(profile);
 }
 
-static BOOL load_gecko()
+static BOOL load_gecko(void)
 {
     nsresult nsres;
     nsIObserver *pStartNotif;
diff --git a/dlls/msvcrt/tests/cpp.c b/dlls/msvcrt/tests/cpp.c
index 583fe47cf39..a0e73cebada 100644
--- a/dlls/msvcrt/tests/cpp.c
+++ b/dlls/msvcrt/tests/cpp.c
@@ -182,7 +182,7 @@ static void* do_call_func2(void *func, void *_this, void* arg)
 #define SETNOFAIL(x,y) x = (void*)GetProcAddress(hMsvcrt,y)
 #define SET(x,y) SETNOFAIL(x,y); ok(x != NULL, "Export '%s' not found\n", y)
 
-static void InitFunctionPtrs()
+static void InitFunctionPtrs(void)
 {
   hMsvcrt = LoadLibraryA("msvcrt.dll");
   ok(hMsvcrt != 0, "LoadLibraryA failed\n");
diff --git a/dlls/msvcrt/tests/dir.c b/dlls/msvcrt/tests/dir.c
index b7d1aa2d2de..3c8ba21c5a4 100644
--- a/dlls/msvcrt/tests/dir.c
+++ b/dlls/msvcrt/tests/dir.c
@@ -31,7 +31,7 @@
 #include <process.h>
 #include <errno.h>
 
-void test_fullpath()
+void test_fullpath(void)
 {
     char full[MAX_PATH];
     char tmppath[MAX_PATH];
diff --git a/dlls/msvcrt/tests/string.c b/dlls/msvcrt/tests/string.c
index 72575a25abb..7fda59e12d7 100644
--- a/dlls/msvcrt/tests/string.c
+++ b/dlls/msvcrt/tests/string.c
@@ -75,7 +75,7 @@ static void test_swab( void ) {
     ok(memcmp(to,expected3,testsize) == 0, "Testing small size %d returned '%*.*s'\n", testsize, testsize, testsize, to);
 }
 
-void test_ismbblead()
+void test_ismbblead(void)
 {
     unsigned int s = '\354';
 
diff --git a/dlls/msvcrtd/debug.c b/dlls/msvcrtd/debug.c
index 90995ad6d29..6f70367a09e 100644
--- a/dlls/msvcrtd/debug.c
+++ b/dlls/msvcrtd/debug.c
@@ -132,7 +132,7 @@ int _CrtDbgReport(int reportType, const char *filename, int linenumber,
 /*********************************************************************
  *		_CrtDumpMemoryLeaks (MSVCRTD.@)
  */
-int _CrtDumpMemoryLeaks()
+int _CrtDumpMemoryLeaks(void)
 {
     return 0;
 }
@@ -140,7 +140,7 @@ int _CrtDumpMemoryLeaks()
 /*********************************************************************
  *		_CrtCheckMemory (MSVCRTD.@)
  */
-int _CrtCheckMemory()
+int _CrtCheckMemory(void)
 {
     /* Note: maybe we could call here our heap validating functions ? */
     return TRUE;
diff --git a/dlls/ntdll/loader.c b/dlls/ntdll/loader.c
index 5996523b3ca..c2e2f36a161 100644
--- a/dlls/ntdll/loader.c
+++ b/dlls/ntdll/loader.c
@@ -2157,7 +2157,7 @@ void __wine_process_init( int argc, char *argv[] )
     WINE_MODREF *wm;
     NTSTATUS status;
     ANSI_STRING func_name;
-    void (* DECLSPEC_NORETURN init_func)();
+    void (* DECLSPEC_NORETURN init_func)(void);
     extern mode_t FILE_umask;
 
     thread_init();
diff --git a/dlls/ntdll/tests/time.c b/dlls/ntdll/tests/time.c
index 5e1070ddc1b..f5c586d5e15 100644
--- a/dlls/ntdll/tests/time.c
+++ b/dlls/ntdll/tests/time.c
@@ -43,7 +43,7 @@ static inline int IsLeapYear(int Year)
 /* start time of the tests */
 TIME_FIELDS tftest = {1889,12,31,23,59,59,0,0};
 
-static void test_pRtlTimeToTimeFields()
+static void test_pRtlTimeToTimeFields(void)
 {
     LARGE_INTEGER litime , liresult;
     TIME_FIELDS tfresult;
diff --git a/dlls/odbc32/proxyodbc.c b/dlls/odbc32/proxyodbc.c
index d6cb221e383..ca6114c66fd 100644
--- a/dlls/odbc32/proxyodbc.c
+++ b/dlls/odbc32/proxyodbc.c
@@ -156,7 +156,7 @@ static PROXYHANDLE gProxyHandle;
         } \
 }
 
-SQLRETURN SQLDummyFunc()
+SQLRETURN SQLDummyFunc(void)
 {
     TRACE("SQLDummyFunc:\n");
     return SQL_SUCCESS;
diff --git a/dlls/quartz/tests/memallocator.c b/dlls/quartz/tests/memallocator.c
index 4acb133bf56..e231f5f1e89 100644
--- a/dlls/quartz/tests/memallocator.c
+++ b/dlls/quartz/tests/memallocator.c
@@ -27,7 +27,7 @@
 #include "dshow.h"
 #include "control.h"
 
-static void CommitDecommitTest()
+static void CommitDecommitTest(void)
 {
     IMemAllocator* pMemAllocator;
     HRESULT hr;
diff --git a/dlls/shdocvw/tests/shortcut.c b/dlls/shdocvw/tests/shortcut.c
index 073d62d3ae8..c12e0bd4425 100644
--- a/dlls/shdocvw/tests/shortcut.c
+++ b/dlls/shdocvw/tests/shortcut.c
@@ -157,7 +157,7 @@ static void unregister_keys(HKEY hRootKey, const struct registry_key *keys, unsi
     }
 }
     
-static void test_ShortcutFolder() {
+static void test_ShortcutFolder(void) {
     LPSHELLFOLDER pDesktopFolder, pWineTestFolder;
     IPersistFolder3 *pWineTestPersistFolder;
     LPITEMIDLIST pidlWineTestFolder, pidlCurFolder;
diff --git a/dlls/shlwapi/ordinal.c b/dlls/shlwapi/ordinal.c
index 36d7173f1fd..06eee927ff0 100644
--- a/dlls/shlwapi/ordinal.c
+++ b/dlls/shlwapi/ordinal.c
@@ -1972,7 +1972,7 @@ HMENU WINAPI SHGetMenuFromID(HMENU hMenu, UINT uID)
  * RETURNS
  *  The color depth of the primary display.
  */
-DWORD WINAPI SHGetCurColorRes()
+DWORD WINAPI SHGetCurColorRes(void)
 {
     HDC hdc;
     DWORD ret;
@@ -2813,7 +2813,7 @@ BOOL WINAPI GUIDFromStringW(LPCWSTR idstr, CLSID *id)
  *  either set to TRUE, or removed depending on whether the browser is deemed
  *  to be integrated.
  */
-DWORD WINAPI WhichPlatform()
+DWORD WINAPI WhichPlatform(void)
 {
   static LPCSTR szIntegratedBrowser = "IntegratedBrowser";
   static DWORD dwState = 0;
@@ -3396,7 +3396,7 @@ HICON WINAPI ExtractIconWrapW(HINSTANCE hInstance, LPCWSTR lpszExeFileName,
 /*************************************************************************
  *      @	[SHLWAPI.376]
  */
-LANGID WINAPI MLGetUILanguage()
+LANGID WINAPI MLGetUILanguage(void)
 {
     FIXME("() stub\n");
     /* FIXME: This should be a forward in the .spec file to the win2k function
diff --git a/dlls/shlwapi/stopwatch.c b/dlls/shlwapi/stopwatch.c
index 4e092a45050..70aa5725707 100644
--- a/dlls/shlwapi/stopwatch.c
+++ b/dlls/shlwapi/stopwatch.c
@@ -55,7 +55,7 @@ WINE_DEFAULT_DEBUG_CHANNEL(shell);
  * NOTES
  *  If this function returns 0, no further StopWatch functions should be called.
  */
-DWORD WINAPI StopWatchMode()
+DWORD WINAPI StopWatchMode(void)
 {
   FIXME("() stub!\n");
   return 0;
@@ -72,7 +72,7 @@ DWORD WINAPI StopWatchMode()
  * RETURNS
  *  Nothing.
  */
-void WINAPI StopWatchFlush()
+void WINAPI StopWatchFlush(void)
 {
   FIXME("() stub!\n");
 }
@@ -188,7 +188,7 @@ void WINAPI StopWatch_MarkJavaStop(LPCWSTR lpszEvent, HWND hWnd, DWORD dwReserve
  * RETURNS
  *  The low 32 bits of the current performance counter reading.
  */
-DWORD WINAPI GetPerfTime()
+DWORD WINAPI GetPerfTime(void)
 {
   static LONG64 iCounterFreq = 0;
   LARGE_INTEGER iCounter;
diff --git a/dlls/user/tests/menu.c b/dlls/user/tests/menu.c
index adc5e6572ca..0ae0d2b4aaf 100644
--- a/dlls/user/tests/menu.c
+++ b/dlls/user/tests/menu.c
@@ -487,7 +487,7 @@ if( !stop) {\
 #define ER 0
 
 
-static void test_menu_iteminfo(  )
+static void test_menu_iteminfo( void )
 {
   int S=sizeof( MENUITEMINFOA);
   int ansi = TRUE;
diff --git a/dlls/user/tests/text.c b/dlls/user/tests/text.c
index 8d079ae7c42..874b6e0ef1e 100644
--- a/dlls/user/tests/text.c
+++ b/dlls/user/tests/text.c
@@ -182,7 +182,7 @@ static void strfmt( char *str, char *strout)
 } \
 
 
-static void test_TabbedText()
+static void test_TabbedText(void)
 {
     HWND hwnd;
     HDC hdc;
diff --git a/dlls/wininet/tests/http.c b/dlls/wininet/tests/http.c
index d037847d46d..1abececbe8e 100644
--- a/dlls/wininet/tests/http.c
+++ b/dlls/wininet/tests/http.c
@@ -838,7 +838,7 @@ static void fill_url_components(LPURL_COMPONENTS lpUrlComponents)
 	lpUrlComponents->dwExtraInfoLength = strlen(lpUrlComponents->lpszExtraInfo);
 }
 
-static void InternetCreateUrlA_test()
+static void InternetCreateUrlA_test(void)
 {
 	URL_COMPONENTS urlComp;
 	LPSTR szUrl;
diff --git a/include/msvcrt/crtdbg.h b/include/msvcrt/crtdbg.h
index f520bf4d559..bb0f40c6631 100644
--- a/include/msvcrt/crtdbg.h
+++ b/include/msvcrt/crtdbg.h
@@ -81,10 +81,10 @@ extern int _crtAssertBusy;
 extern int _crtBreakAlloc;
 extern int _crtDbgFlag;
 
-int   _CrtCheckMemory();
+int   _CrtCheckMemory(void);
 int   _CrtDbgReport(int reportType, const char *filename, int linenumber,
                     const char *moduleName, const char *format, ...);
-int   _CrtDumpMemoryLeaks();
+int   _CrtDumpMemoryLeaks(void);
 int   _CrtSetBreakAlloc(int new);
 int   _CrtSetDbgFlag(int new);
 void *_CrtSetDumpClient(void *dumpClient);
diff --git a/loader/kthread.c b/loader/kthread.c
index e27eb2ee829..eb612a7f754 100644
--- a/loader/kthread.c
+++ b/loader/kthread.c
@@ -564,7 +564,7 @@ strong_alias(__pthread_kill_other_threads_np, pthread_kill_other_threads_np);
 
 static pthread_mutex_t atfork_mutex = PTHREAD_MUTEX_INITIALIZER;
 
-typedef void (*atfork_handler)();
+typedef void (*atfork_handler)(void);
 static atfork_handler atfork_prepare[MAX_ATFORK];
 static atfork_handler atfork_parent[MAX_ATFORK];
 static atfork_handler atfork_child[MAX_ATFORK];
diff --git a/loader/preloader.c b/loader/preloader.c
index 6f07692a41b..1ca6d831009 100644
--- a/loader/preloader.c
+++ b/loader/preloader.c
@@ -153,7 +153,7 @@ struct wld_link_map {
  * build the preloader with "-nostartfiles -nodefaultlibs", we have to
  * provide our own (empty) version, otherwise linker fails.
  */
-void __bb_init_func() { return; }
+void __bb_init_func(void) { return; }
 
 /* similar to the above but for -fstack-protector */
 void *__stack_chk_guard = 0;
diff --git a/programs/notepad/main.c b/programs/notepad/main.c
index 4d7e39c684f..0b10c57ca29 100644
--- a/programs/notepad/main.c
+++ b/programs/notepad/main.c
@@ -53,7 +53,7 @@ VOID SetFileName(LPCWSTR szFileName)
  *
  *  Initialize font for the edit window
  */
-static VOID NOTEPAD_InitFont()
+static VOID NOTEPAD_InitFont(void)
 {
     LOGFONT *lf = &Globals.lfFont;
     static const WCHAR systemW[] = { 'S','y','s','t','e','m',0 };