diff --git a/engine/cdll_int.h b/engine/cdll_int.h
index a1e5254c..e407cced 100644
--- a/engine/cdll_int.h
+++ b/engine/cdll_int.h
@@ -213,14 +213,14 @@ typedef struct cl_enginefuncs_s
 	int	(*pfnRandomLong)( int lLow, int lHigh );
 	void	(*pfnHookEvent)( const char *name, void ( *pfnEvent )( struct event_args_s *args ));
 
-	int	(*Con_IsVisible) ();
+	int	(*Con_IsVisible) ( void );
 	const char *(*pfnGetGameDirectory)( void );
 	struct cvar_s *(*pfnGetCvarPointer)( const char *szName );
 	const char *(*Key_LookupBinding)( const char *pBinding );
 	const char *(*pfnGetLevelName)( void );
 	void	(*pfnGetScreenFade)( struct screenfade_s *fade );
 	void	(*pfnSetScreenFade)( struct screenfade_s *fade );
-	void*	(*VGui_GetPanel)( );
+	void*	(*VGui_GetPanel)( void );
 	void	(*VGui_ViewportPaintBackground)( int extents[4] );
 
 	byte*	(*COM_LoadFile)( const char *path, int usehunk, int *pLength );
diff --git a/engine/client/cl_efx.c b/engine/client/cl_efx.c
index f67187e7..c3ff8505 100644
--- a/engine/client/cl_efx.c
+++ b/engine/client/cl_efx.c
@@ -2061,7 +2061,7 @@ void CL_ReadPointFile_f( void )
 	else Con_Printf( "map %s has no leaks!\n", clgame.mapname );
 }
 
-void CL_FreeDeadBeams()
+void CL_FreeDeadBeams( void )
 {
 	BEAM *pBeam, *pNext, *pPrev = NULL;
 	// draw temporary entity beams
diff --git a/engine/client/cl_mobile.c b/engine/client/cl_mobile.c
index 00dc1145..b6fd5cff 100644
--- a/engine/client/cl_mobile.c
+++ b/engine/client/cl_mobile.c
@@ -44,7 +44,7 @@ static void pfnVibrate( float life, char flags )
 	Platform_Vibrate( life * vibration_length->value, flags );
 }
 
-static void Vibrate_f()
+static void Vibrate_f( void )
 {
 	if( Cmd_Argc() != 2 )
 	{
diff --git a/engine/client/ref_common.c b/engine/client/ref_common.c
index e919d4ec..269b98f5 100644
--- a/engine/client/ref_common.c
+++ b/engine/client/ref_common.c
@@ -536,7 +536,7 @@ static qboolean R_LoadRenderer( const char *refopt )
 	return true;
 }
 
-static void SetWidthAndHeightFromCommandLine()
+static void SetWidthAndHeightFromCommandLine( void )
 {
 	int width, height;
 
@@ -552,7 +552,7 @@ static void SetWidthAndHeightFromCommandLine()
 	R_SaveVideoMode( width, height );
 }
 
-static void SetFullscreenModeFromCommandLine( )
+static void SetFullscreenModeFromCommandLine( void )
 {
 #ifndef __ANDROID__
 	if ( Sys_CheckParm("-fullscreen") )
diff --git a/engine/client/vgui/vgui_draw.c b/engine/client/vgui/vgui_draw.c
index 4efd295f..c8e25a56 100644
--- a/engine/client/vgui/vgui_draw.c
+++ b/engine/client/vgui/vgui_draw.c
@@ -533,19 +533,19 @@ void VGui_MouseMove( int x, int y )
 		vgui.MouseMove( x / xscale, y / yscale );
 }
 
-void VGui_Paint()
+void VGui_Paint( void )
 {
 	if(vgui.initialized)
 		vgui.Paint();
 }
 
-void VGui_RunFrame()
+void VGui_RunFrame( void )
 {
 	//stub
 }
 
 
-void *GAME_EXPORT VGui_GetPanel()
+void *GAME_EXPORT VGui_GetPanel( void )
 {
 	if( vgui.initialized )
 		return vgui.GetPanel();
diff --git a/engine/client/vgui/vgui_draw.h b/engine/client/vgui/vgui_draw.h
index 58661939..bf9c4396 100644
--- a/engine/client/vgui/vgui_draw.h
+++ b/engine/client/vgui/vgui_draw.h
@@ -27,12 +27,12 @@ extern "C" {
 //
 void VGui_Startup( const char *clientlib, int width, int height );
 void VGui_Shutdown( void );
-void VGui_Paint();
-void VGui_RunFrame();
+void VGui_Paint( void );
+void VGui_RunFrame( void );
 void VGui_KeyEvent( int key, int down );
 void VGui_MouseMove( int x, int y );
 qboolean VGui_IsActive( void );
-void *VGui_GetPanel();
+void *VGui_GetPanel( void );
 #ifdef __cplusplus
 }
 #endif
diff --git a/engine/client/vid_common.c b/engine/client/vid_common.c
index 416e6dba..a2a315a7 100644
--- a/engine/client/vid_common.c
+++ b/engine/client/vid_common.c
@@ -161,7 +161,7 @@ static void VID_Mode_f( void )
 	R_ChangeDisplaySettings( w, h, Cvar_VariableInteger( "fullscreen" ) );
 }
 
-void VID_Init()
+void VID_Init( void )
 {
 	// system screen width and height (don't suppose for change from console at all)
 	Cvar_Get( "width", "0", FCVAR_RENDERINFO|FCVAR_VIDRESTART, "screen width" );
diff --git a/engine/common/identification.c b/engine/common/identification.c
index 0ee61750..7ca71598 100644
--- a/engine/common/identification.c
+++ b/engine/common/identification.c
@@ -564,7 +564,7 @@ uint ID_CheckRawId( bloomfilter_t filter )
 #define SYSTEM_XOR_MASK 0x10331c2dce4c91db
 #define GAME_XOR_MASK 0x7ffc48fbac1711f1
 
-void ID_Check()
+void ID_Check( void )
 {
 	uint weight = BloomFilter_Weight( id );
 	uint mincount = weight >> 2;
@@ -588,7 +588,7 @@ void ID_Check()
 #endif
 }
 
-const char *ID_GetMD5()
+const char *ID_GetMD5( void )
 {
 	if( id_customid[0] )
 		return id_customid;
diff --git a/engine/common/lib_common.c b/engine/common/lib_common.c
index 7c30f37e..8a361794 100644
--- a/engine/common/lib_common.c
+++ b/engine/common/lib_common.c
@@ -20,12 +20,12 @@ GNU General Public License for more details.
 
 static char s_szLastError[1024] = "";
 
-const char *COM_GetLibraryError()
+const char *COM_GetLibraryError( void )
 {
 	return s_szLastError;
 }
 
-void COM_ResetLibraryError()
+void COM_ResetLibraryError( void )
 {
 	s_szLastError[0] = 0;
 }
diff --git a/engine/common/miniz.h b/engine/common/miniz.h
index 4ad18920..fd8c02fd 100644
--- a/engine/common/miniz.h
+++ b/engine/common/miniz.h
@@ -3091,7 +3091,7 @@ void *tdefl_write_image_to_png_file_in_memory(const void *pImage, int w, int h,
 /* Allocate the tdefl_compressor and tinfl_decompressor structures in C so that */
 /* non-C language bindings to tdefL_ and tinfl_ API don't need to worry about */
 /* structure size and allocation mechanism. */
-tdefl_compressor *tdefl_compressor_alloc()
+tdefl_compressor *tdefl_compressor_alloc( void )
 {
     return (tdefl_compressor *)MZ_MALLOC(sizeof(tdefl_compressor));
 }
@@ -3832,7 +3832,7 @@ int tinfl_decompress_mem_to_callback(const void *pIn_buf, size_t *pIn_buf_size,
 }
 
 #ifndef MINIZ_NO_MALLOC
-tinfl_decompressor *tinfl_decompressor_alloc()
+tinfl_decompressor *tinfl_decompressor_alloc( void )
 {
     tinfl_decompressor *pDecomp = (tinfl_decompressor *)MZ_MALLOC(sizeof(tinfl_decompressor));
     if (pDecomp)
diff --git a/engine/common/system.c b/engine/common/system.c
index c4d501c1..1b1a3bd8 100644
--- a/engine/common/system.c
+++ b/engine/common/system.c
@@ -49,7 +49,7 @@ double GAME_EXPORT Sys_DoubleTime( void )
 
 #if defined __linux__ || ( defined _WIN32 && !defined XASH_64BIT )
 	#undef DEBUG_BREAK
-	qboolean Sys_DebuggerPresent(); // see sys_linux.c
+	qboolean Sys_DebuggerPresent( void ); // see sys_linux.c
 	#ifdef _MSC_VER
 		#define DEBUG_BREAK \
 			if( Sys_DebuggerPresent() ) \
diff --git a/engine/platform/platform.h b/engine/platform/platform.h
index c5c15b12..33e9b186 100644
--- a/engine/platform/platform.h
+++ b/engine/platform/platform.h
@@ -100,15 +100,15 @@ qboolean  R_Init_Video( const int type );
 void      R_Free_Video( void );
 qboolean  VID_SetMode( void );
 rserr_t   R_ChangeDisplaySettings( int width, int height, qboolean fullscreen );
-int       R_MaxVideoModes();
+int       R_MaxVideoModes( void );
 vidmode_t*R_GetVideoMode( int num );
 void*     GL_GetProcAddress( const char *name ); // RenderAPI requirement
 void      GL_UpdateSwapInterval( void );
 int GL_SetAttribute( int attr, int val );
 int GL_GetAttribute( int attr, int *val );
-void GL_SwapBuffers();
-void *SW_LockBuffer();
-void SW_UnlockBuffer();
+void GL_SwapBuffers( void );
+void *SW_LockBuffer( void );
+void SW_UnlockBuffer( void );
 qboolean SW_CreateBuffer( int width, int height, uint *stride, uint *bpp, uint *r, uint *g, uint *b );
 
 /*
diff --git a/engine/platform/sdl/vid_sdl.c b/engine/platform/sdl/vid_sdl.c
index 99cf6f3a..cc97150c 100644
--- a/engine/platform/sdl/vid_sdl.c
+++ b/engine/platform/sdl/vid_sdl.c
@@ -143,7 +143,7 @@ qboolean SW_CreateBuffer( int width, int height, uint *stride, uint *bpp, uint *
 	return false;
 }
 
-void *SW_LockBuffer()
+void *SW_LockBuffer( void )
 {
 	if( sw.renderer )
 	{
@@ -181,7 +181,7 @@ void *SW_LockBuffer()
 	}
 }
 
-void SW_UnlockBuffer()
+void SW_UnlockBuffer( void )
 {
 	if( sw.renderer )
 	{
@@ -713,8 +713,7 @@ static void GL_SetupAttributes( void )
 	ref.dllFuncs.GL_SetupAttributes( glw_state.safe );
 }
 
-
-void GL_SwapBuffers()
+void GL_SwapBuffers( void )
 {
 	SDL_GL_SwapWindow( host.hWnd );
 }
diff --git a/engine/ref_api.h b/engine/ref_api.h
index 848cc5c8..9c4b546e 100644
--- a/engine/ref_api.h
+++ b/engine/ref_api.h
@@ -279,7 +279,7 @@ typedef struct ref_api_s
 	void	(*CL_CenterPrint)( const char *s, float y );
 	void (*Con_DrawStringLen)( const char *pText, int *length, int *height );
 	int (*Con_DrawString)( int x, int y, const char *string, rgba_t setColor );
-	void	(*CL_DrawCenterPrint)();
+	void	(*CL_DrawCenterPrint)( void );
 
 	// entity management
 	struct cl_entity_s *(*GetLocalPlayer)( void );
@@ -377,12 +377,12 @@ typedef struct ref_api_s
 	int   (*GL_SetAttribute)( int attr, int value );
 	int   (*GL_GetAttribute)( int attr, int *value );
 	void *(*GL_GetProcAddress)( const char *name );
-	void (*GL_SwapBuffers)();
+	void (*GL_SwapBuffers)( void );
 
 	// SW
 	qboolean (*SW_CreateBuffer)( int width, int height, uint *stride, uint *bpp, uint *r, uint *g, uint *b );
-	void *(*SW_LockBuffer)();
-	void (*SW_UnlockBuffer)();
+	void *(*SW_LockBuffer)( void );
+	void (*SW_UnlockBuffer)( void );
 
 	// gamma
 	void (*BuildGammaTable)( float lightgamma, float brightness );
diff --git a/ref_gl/gl_local.h b/ref_gl/gl_local.h
index 23166d0c..b9ca8679 100644
--- a/ref_gl/gl_local.h
+++ b/ref_gl/gl_local.h
@@ -430,8 +430,8 @@ void GL_RebuildLightmaps( void );
 void GL_InitRandomTable( void );
 void GL_BuildLightmaps( void );
 void GL_ResetFogColor( void );
-void R_GenerateVBO();
-void R_ClearVBO();
+void R_GenerateVBO( void );
+void R_ClearVBO( void );
 void R_AddDecalVBO( decal_t *pdecal, msurface_t *surf );
 
 //
diff --git a/ref_gl/gl_opengl.c b/ref_gl/gl_opengl.c
index f71bd281..19595bd2 100644
--- a/ref_gl/gl_opengl.c
+++ b/ref_gl/gl_opengl.c
@@ -587,7 +587,7 @@ void GL_InitExtensionsGLES( void )
 	}
 }
 #else
-void GL_InitExtensionsBigGL()
+void GL_InitExtensionsBigGL( void )
 {
 	// intialize wrapper type
 	glConfig.context = CONTEXT_TYPE_GL;
diff --git a/ref_gl/gl_rsurf.c b/ref_gl/gl_rsurf.c
index eaae297f..3e9d43df 100644
--- a/ref_gl/gl_rsurf.c
+++ b/ref_gl/gl_rsurf.c
@@ -653,7 +653,7 @@ static int LM_AllocBlock( int w, int h, int *x, int *y )
 	return true;
 }
 
-static void LM_UploadDynamicBlock()
+static void LM_UploadDynamicBlock( void )
 {
 	int	height = 0, i;
 
@@ -1781,7 +1781,7 @@ R_GenerateVBO
 Allocate memory for arrays, fill it with vertex attribs and upload to GPU
 ===================
 */
-void R_GenerateVBO()
+void R_GenerateVBO( void )
 {
 	int numtextures = WORLDMODEL->numtextures;
 	int numlightmaps = gl_lms.current_lightmap_texture;
@@ -2033,7 +2033,7 @@ R_ClearVBO
 free all vbo data
 =============
 */
-void R_ClearVBO()
+void R_ClearVBO( void )
 {
 	vboarray_t *vbo;