diff --git a/unix/xserver/hw/vnc/vncExtInit.h b/unix/xserver/hw/vnc/vncExtInit.h
index 0b4abfd..c363f19 100644
--- a/unix/xserver/hw/vnc/vncExtInit.h
+++ b/unix/xserver/hw/vnc/vncExtInit.h
@@ -49,7 +49,7 @@ struct dlp_mimetype_t {
   char mime[32];
 };
 
-unsigned dlp_num_mimetypes();
+unsigned dlp_num_mimetypes(void);
 const char *dlp_get_mimetype(const unsigned i);
 
 extern int vncInetdSock;
@@ -68,7 +68,7 @@ int vncGetSendPrimary(void);
 void vncUpdateDesktopName(void);
 
 void vncAnnounceClipboard(int available);
-void vncClearBinaryClipboardData();
+void vncClearBinaryClipboardData(void);
 void vncSendBinaryClipboardData(const char* mime, const unsigned char *data,
                                 const unsigned len);
 void vncGetBinaryClipboardData(const char *mime, const unsigned char **ptr,
diff --git a/unix/xserver/hw/vnc/xvnc.c b/unix/xserver/hw/vnc/xvnc.c
index 5dac75c..d2c2b63 100644
--- a/unix/xserver/hw/vnc/xvnc.c
+++ b/unix/xserver/hw/vnc/xvnc.c
@@ -1475,7 +1475,7 @@ int vncRandRCreateScreenOutputs(int scrIdx, int extraOutputs)
 
 /* Creating and modifying modes, used by XserverDesktop and init here */
 
-int vncRandRCanCreateModes()
+int vncRandRCanCreateModes(void)
 {
     return 1;
 }