diff --git a/src/font/freetype1.c b/src/font/freetype1.c
index 7e3e1ae0..2fbf20fc 100644
--- a/src/font/freetype1.c
+++ b/src/font/freetype1.c
@@ -294,7 +294,7 @@ static void start_str_output (LOGFONT* logfont, DEVFONT* devfont)
 /* call this function before getting the bitmap/pixmap of the char
  * to get the bbox of the char */
 static int get_glyph_bbox (LOGFONT* logfont, DEVFONT* devfont, 
-                const Glyph32 glyph_value, 
+                Glyph32 glyph_value, 
                 int* px, int* py, int* pwidth, int* pheight)
 {
     TT_UShort uni_char;
@@ -440,7 +440,7 @@ static int get_glyph_bbox (LOGFONT* logfont, DEVFONT* devfont,
 /* call this function to get the bitmap/pixmap of the char */ 
 static const void* 
 char_bitmap_pixmap (LOGFONT* logfont, DEVFONT* devfont, 
-                const Glyph32 glyph_value, SIZE* sz, int* pitch, BOOL is_grey) 
+                Glyph32 glyph_value, SIZE* sz, int* pitch, BOOL is_grey) 
 {
     TT_Raster_Map Raster;
     TT_Error error;
@@ -538,14 +538,14 @@ char_bitmap_pixmap (LOGFONT* logfont, DEVFONT* devfont,
 }
 
 static const void* get_glyph_monobitmap (LOGFONT* logfont, DEVFONT* devfont,
-            const Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
+            Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
 {
     if (scale) *scale = 1;
     return char_bitmap_pixmap (logfont, devfont, glyph_value, sz, pitch, FALSE);
 }
 
 static const void* get_glyph_greybitmap (LOGFONT* logfont, DEVFONT* devfont,
-            const Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
+            Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
 {
     if (scale) *scale = 1;
     return char_bitmap_pixmap (logfont, devfont, glyph_value, sz, pitch, TRUE);
@@ -554,7 +554,7 @@ static const void* get_glyph_greybitmap (LOGFONT* logfont, DEVFONT* devfont,
 /* call this function after getting the bitmap/pixmap of the char
  * to get the advance of the char */
 static int get_glyph_advance (LOGFONT* logfont, DEVFONT* devfont, 
-            const Glyph32 glyph_value, int* px, int* py)
+            Glyph32 glyph_value, int* px, int* py)
 {
     TT_Pos vec_x, vec_y;
     TTFINSTANCEINFO* ttf_inst_info = TTF_INST_INFO_P (devfont);
diff --git a/src/font/freetype2.c b/src/font/freetype2.c
index a05b5832..11f4cc38 100644
--- a/src/font/freetype2.c
+++ b/src/font/freetype2.c
@@ -324,7 +324,7 @@ load_or_search_glyph (FTINSTANCEINFO* ft_inst_info, FT_Face* face,
  * to get the bbox of the char */
 static int
 get_glyph_bbox (LOGFONT* logfont, DEVFONT* devfont,
-                const Glyph32 glyph_value,
+                Glyph32 glyph_value,
                 int* px, int* py, int* pwidth, int* pheight)
 {
 
@@ -479,7 +479,7 @@ press_bitmap (void* buffer, int width, int rows, int pitch)
 /* call this function to get the bitmap/pixmap of the char */
 static const void*
 char_bitmap_pixmap (LOGFONT* logfont, DEVFONT* devfont,
-        const Glyph32 glyph_value, SIZE* sz, int* pitch, BOOL is_grey)
+        Glyph32 glyph_value, SIZE* sz, int* pitch, BOOL is_grey)
 {
     FT_BitmapGlyph  glyph_bitmap;
     FT_Bitmap*      source;
@@ -616,14 +616,14 @@ char_bitmap_pixmap (LOGFONT* logfont, DEVFONT* devfont,
 
 static const void*
 get_glyph_monobitmap (LOGFONT* logfont, DEVFONT* devfont,
-        const Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
+        Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
 {
     if (scale) *scale = 1;
     return char_bitmap_pixmap (logfont, devfont, glyph_value, sz, pitch, FALSE);
 }
 static const void*
 get_glyph_greybitmap (LOGFONT* logfont, DEVFONT* devfont,
-            const Glyph32 glyph_value, SIZE* sz, int* pitch,
+            Glyph32 glyph_value, SIZE* sz, int* pitch,
             unsigned short* scale)
 {
     if (scale) *scale = 1;
@@ -648,7 +648,7 @@ start_str_output (LOGFONT* logfont, DEVFONT* devfont)
  * to get the advance of the char */
 static int
 get_glyph_advance (LOGFONT* logfont, DEVFONT* devfont,
-    const Glyph32 glyph_value, int* px, int* py)
+    Glyph32 glyph_value, int* px, int* py)
 {
 	FT_Fixed advance;
     FTINSTANCEINFO* ft_inst_info = FT_INST_INFO_P (devfont);
diff --git a/src/font/qpf.c b/src/font/qpf.c
index 7da0c09d..139f8afc 100644
--- a/src/font/qpf.c
+++ b/src/font/qpf.c
@@ -329,7 +329,7 @@ static int get_font_descent (LOGFONT* logfont, DEVFONT* devfont)
 }
 
 static const void* get_glyph_monobitmap (LOGFONT* logfont, DEVFONT* devfont,
-            const Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
+            Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
 {
     unsigned int uc16;
     QPF_GLYPH* glyph;
diff --git a/src/font/rawbitmap.c b/src/font/rawbitmap.c
index 1394df0a..f351d08a 100644
--- a/src/font/rawbitmap.c
+++ b/src/font/rawbitmap.c
@@ -208,7 +208,7 @@ static int get_font_descent (LOGFONT* logfont, DEVFONT* devfont)
 }
 
 static const void* get_glyph_monobitmap (LOGFONT* logfont, DEVFONT* devfont,
-            const Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
+            Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
 {
     int bitmap_size;
     Glyph32 glyph_tmp = glyph_value;
diff --git a/src/font/scripteasy.c b/src/font/scripteasy.c
index 7989f1ab..35637a18 100644
--- a/src/font/scripteasy.c
+++ b/src/font/scripteasy.c
@@ -466,7 +466,7 @@ static const void* get_glyph_greybitmap (LOGFONT* logfont, DEVFONT* devfont,
 }
 
 static const void* get_glyph_monobitmap (LOGFONT* logfont, DEVFONT* devfont,
-            const Glyph32 glyph_value, int* pitch, unsigned short* scale)
+            Glyph32 glyph_value, int* pitch, unsigned short* scale)
 {
     seunichar16 wc;
     SeLogFont   selogfont;
diff --git a/src/font/upf.c b/src/font/upf.c
index 9ab83409..ceb711a1 100644
--- a/src/font/upf.c
+++ b/src/font/upf.c
@@ -279,7 +279,7 @@ print_bitmap(char* bits, int width, int height, int pitch)
 #endif
 
 static const void* get_glyph_monobitmap (LOGFONT* logfont, DEVFONT* devfont,
-        const Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
+        Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
 {
     unsigned int uc16;
     UPFGLYPH* glyph;
diff --git a/src/font/varbitmap.c b/src/font/varbitmap.c
index b2440e11..3d814da7 100644
--- a/src/font/varbitmap.c
+++ b/src/font/varbitmap.c
@@ -237,10 +237,9 @@ static int get_glyph_advance (LOGFONT* logfont, DEVFONT* devfont,
 }
 
 static const void* get_glyph_monobitmap (LOGFONT* logfont, DEVFONT* devfont,
-            const Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
+            Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale)
 {
     int offset;
-    Glyph32 eff_value = glyph_value;
     Glyph32 first_value;
     Glyph32 last_value;
     VBFINFO* vbf_info = VARFONT_INFO_P (devfont);
@@ -249,13 +248,13 @@ static const void* get_glyph_monobitmap (LOGFONT* logfont, DEVFONT* devfont,
     last_value = vbf_info->last_glyph;
 
     if (glyph_value < first_value || glyph_value > last_value)
-        eff_value = vbf_info->def_glyph;
+        glyph_value = vbf_info->def_glyph;
 
     if (vbf_info->bits_offset == NULL)
         offset = (((size_t)vbf_info->max_width + 7) >> 3) * vbf_info->height 
-                    * (eff_value - first_value);
+                    * (glyph_value - first_value);
     else {
-        offset = vbf_info->bits_offset [eff_value - vbf_info->first_glyph];
+        offset = vbf_info->bits_offset [glyph_value - vbf_info->first_glyph];
 #if MGUI_BYTEORDER == MGUI_BIG_ENDIAN
         if (vbf_info->font_size)
             offset = ArchSwap16 (offset);
diff --git a/src/ial/dummy.c b/src/ial/dummy.c
index 32cf891d..175c2170 100644
--- a/src/ial/dummy.c
+++ b/src/ial/dummy.c
@@ -1,39 +1,39 @@
 /*
- *   This file is part of MiniGUI, a mature cross-platform windowing 
+ *   This file is part of MiniGUI, a mature cross-platform windowing
  *   and Graphics User Interface (GUI) support system for embedded systems
  *   and smart IoT devices.
- * 
+ *
  *   Copyright (C) 2002~2018, Beijing FMSoft Technologies Co., Ltd.
  *   Copyright (C) 1998~2002, WEI Yongming
- * 
+ *
  *   This program is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
  *   the Free Software Foundation, either version 3 of the License, or
  *   (at your option) any later version.
- * 
+ *
  *   This program is distributed in the hope that it will be useful,
  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *   GNU General Public License for more details.
- * 
+ *
  *   You should have received a copy of the GNU General Public License
  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
- * 
+ *
  *   Or,
- * 
+ *
  *   As this program is a library, any link to this program must follow
  *   GNU General Public License version 3 (GPLv3). If you cannot accept
  *   GPLv3, you need to be licensed from FMSoft.
- * 
+ *
  *   If you have got a commercial license of this program, please use it
  *   under the terms and conditions of the commercial license.
- * 
+ *
  *   For more information about the commercial license, please refer to
  *   <http://www.minigui.com/en/about/licensing-policy/>.
  */
 /*
 ** dummy.c: The dummy IAL engine.
-** 
+**
 ** Created by Wei Yongming, 2001/09/13
 */
 
@@ -53,9 +53,9 @@ static int mouse_x, mouse_y, mouse_button;
 
 typedef struct tagPOS
 {
-	short x;
-	short y;
-	short b;
+    short x;
+    short y;
+    short b;
 } POS;
 
 /************************  Low Level Input Operations **********************/
@@ -64,28 +64,28 @@ typedef struct tagPOS
  */
 static int mouse_update(void)
 {
-	return 1;
+    return 1;
 }
 
 static void mouse_getxy (int* x, int* y)
 {
-	*x = mouse_x;
+    *x = mouse_x;
     *y = mouse_y;
 }
 
 static int mouse_getbutton(void)
 {
-	return mouse_button;
+    return mouse_button;
 }
 
 static int keyboard_update(void)
 {
-	return 0;
+    return 0;
 }
 
 static const char * keyboard_get_state (void)
 {
-	return NULL;
+    return NULL;
 }
 
 static int wait_event (int which, int maxfd, fd_set *in, fd_set *out, fd_set *except,
@@ -93,23 +93,25 @@ static int wait_event (int which, int maxfd, fd_set *in, fd_set *out, fd_set *ex
 {
 #ifdef _MGRM_THREADS
     __mg_os_time_delay (300);
+    timeout->tv_sec = 0;
+    timeout->tv_usec = 0;
 #else
-	fd_set rfds;
-	int	e;
+    fd_set rfds;
+    int    e;
 
     if (!in) {
         in = &rfds;
         mg_fd_zero (in);
     }
 
-	e = mg_select (maxfd + 1, in, out, except, timeout) ;
+    e = mg_select (maxfd + 1, in, out, except, timeout) ;
 
     if (e < 0) {
-		return -1;
-	}
+        return -1;
+    }
 #endif
 
-	return 0;
+    return 0;
 }
 
 BOOL InitDummyInput (INPUT* input, const char* mdev, const char* mtype)
@@ -125,9 +127,9 @@ BOOL InitDummyInput (INPUT* input, const char* mdev, const char* mtype)
     input->set_leds = NULL;
 
     input->wait_event = wait_event;
-	mouse_x = 0;
-	mouse_y = 0;
-	mouse_button= 0;
+    mouse_x = 0;
+    mouse_y = 0;
+    mouse_button= 0;
     return TRUE;
 }
 
diff --git a/src/include/devfont.h b/src/include/devfont.h
index 44cd8ba8..8bc94b3a 100644
--- a/src/include/devfont.h
+++ b/src/include/devfont.h
@@ -225,11 +225,11 @@ struct _FONTOPS
 
     /** The method to get mono-bitmap function. */
     const void* (*get_glyph_monobitmap) (LOGFONT* logfont, DEVFONT* devfont, 
-            const Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale);
+            Glyph32 glyph_value, SIZE* sz, int* pitch, unsigned short* scale);
 
     /** The method to get grey bitmap, pitch and scale function */
     const void* (*get_glyph_greybitmap) (LOGFONT* logfont, DEVFONT* devfont, 
-            const Glyph32 galph_value, SIZE* sz, int* pitch, unsigned short* scale);
+            Glyph32 galph_value, SIZE* sz, int* pitch, unsigned short* scale);
 
     /** The method to get the pre-rendered bitmap of one glyph. */
     int (*get_glyph_prbitmap) (LOGFONT* logfont, DEVFONT* devfont,