diff --git a/dos/pdcsetsc.c b/dos/pdcsetsc.c
index e09e5612..a27834b6 100644
--- a/dos/pdcsetsc.c
+++ b/dos/pdcsetsc.c
@@ -76,6 +76,7 @@ int PDC_curs_set(int visibility)
 
 void PDC_set_title(const char *title)
 {
+    INTENTIONALLY_UNUSED_PARAMETER(title);
     PDC_LOG(("PDC_set_title() - called: <%s>\n", title));
 }
 
diff --git a/dosvga/pdckbd.c b/dosvga/pdckbd.c
index b837f56e..9214a31d 100644
--- a/dosvga/pdckbd.c
+++ b/dosvga/pdckbd.c
@@ -80,6 +80,7 @@ static const unsigned short button_map[3] = {0, 2, 1};
 
 void PDC_set_keyboard_binary(bool on)
 {
+    INTENTIONALLY_UNUSED_PARAMETER(on);
     PDC_LOG(("PDC_set_keyboard_binary() - called\n"));
 
 #ifdef __DJGPP__
diff --git a/dosvga/pdcscrn.c b/dosvga/pdcscrn.c
index 139aa888..f5e4d851 100644
--- a/dosvga/pdcscrn.c
+++ b/dosvga/pdcscrn.c
@@ -1370,22 +1370,26 @@ static int _vgafont_open(void)
 
 static void _vgafont_close(bool bold)
 {
+    INTENTIONALLY_UNUSED_PARAMETER(bold);
     /* no operation */
 }
 
 static unsigned _vgafont_char_width(bool bold)
 {
+    INTENTIONALLY_UNUSED_PARAMETER(bold);
     return 8;
 }
 
 static unsigned _vgafont_char_height(bool bold)
 {
+    INTENTIONALLY_UNUSED_PARAMETER(bold);
     return 14;
 }
 
 static const unsigned char *_vgafont_glyph_data(bool bold, unsigned long pos)
 {
     unsigned pos437;
+    INTENTIONALLY_UNUSED_PARAMETER(bold);
 #ifdef PDC_WIDE
     pos437 = _unicode_to_cp437(pos);
 #else
@@ -1734,4 +1738,8 @@ and probably never will.         */
 void PDC_set_resize_limits( const int new_min_lines, const int new_max_lines,
                   const int new_min_cols, const int new_max_cols)
 {
+    INTENTIONALLY_UNUSED_PARAMETER(new_min_lines);
+    INTENTIONALLY_UNUSED_PARAMETER(new_max_lines);
+    INTENTIONALLY_UNUSED_PARAMETER(new_min_cols);
+    INTENTIONALLY_UNUSED_PARAMETER(new_max_cols);
 }
diff --git a/dosvga/pdcsetsc.c b/dosvga/pdcsetsc.c
index 12b3811e..dd11b394 100644
--- a/dosvga/pdcsetsc.c
+++ b/dosvga/pdcsetsc.c
@@ -73,6 +73,7 @@ int PDC_curs_set(int visibility)
 
 void PDC_set_title(const char *title)
 {
+    INTENTIONALLY_UNUSED_PARAMETER(title);
     PDC_LOG(("PDC_set_title() - called: <%s>\n", title));
 }