diff --git a/clients/lcdproc/iface.c b/clients/lcdproc/iface.c
index 0f0e3d5..29c1813 100644
--- a/clients/lcdproc/iface.c
+++ b/clients/lcdproc/iface.c
@@ -49,7 +49,7 @@ static int transfer_screen = 0;  /* by default, transfer screen is not shown */
 
 /* reads and parses configuration file */
 static int
-iface_process_configfile()
+iface_process_configfile(void)
 {
 	const char *unit;
 
diff --git a/clients/lcdproc/machine.h b/clients/lcdproc/machine.h
index 40dc680..2ad7477 100644
--- a/clients/lcdproc/machine.h
+++ b/clients/lcdproc/machine.h
@@ -1,6 +1,12 @@
 /** \file machine.h
  * Common data types and function declarations
  * for OS specific sources in \c machine_{Darwin,Linux,SunOS,*BSD}.c.
+ *
+ * In order to port the lcdproc client to a new cwoperating system,
+ * a new file \c machine_XXX.c (where \c XXX = OS name) needs to be
+ * created, that provides functions to the function declarations below.
+ * The aleady existing \c machine_*.c files can be used as examples.
+ *
  */
 
 #ifndef _lcdproc_machine_h_
diff --git a/clients/lcdproc/main.c b/clients/lcdproc/main.c
index 0ae66fc..e8e55c9 100644
--- a/clients/lcdproc/main.c
+++ b/clients/lcdproc/main.c
@@ -60,7 +60,7 @@ static struct utsname unamebuf;
 
 static void HelpScreen(int exit_state);
 static void exit_program(int val);
-static void main_loop();
+static void main_loop(void);
 static int process_configfile(char *cfgfile);
 
 
@@ -115,25 +115,25 @@ char *configfile = NULL;
 char *displayname = NULL;
 
 
-const char *get_hostname()
+const char *get_hostname(void)
 {
 	return(unamebuf.nodename);
 }
 
 
-const char *get_sysname()
+const char *get_sysname(void)
 {
 	return(unamebuf.sysname);
 }
 
 
-const char *get_sysrelease()
+const char *get_sysrelease(void)
 {
 	return(unamebuf.release);
 }
 
 
-int set_mode(int shortname, char *longname, int state)
+static int set_mode(int shortname, char *longname, int state)
 {
 	int k;
 
@@ -158,7 +158,7 @@ int set_mode(int shortname, char *longname, int state)
 }
 
 
-void clear_modes()
+static void clear_modes(void)
 {
 	int k;
 
@@ -512,7 +512,7 @@ menus_init ()
 // Main program loop...
 //
 void
-main_loop()
+main_loop(void)
 {
 	int i = 0, j;
 	int connected = 0;
diff --git a/clients/lcdproc/main.h b/clients/lcdproc/main.h
index 9a58d12..24709f9 100644
--- a/clients/lcdproc/main.h
+++ b/clients/lcdproc/main.h
@@ -57,9 +57,9 @@ typedef struct mode
 #define LCD_MAX_WIDTH	80
 #define LCD_MAX_HEIGHT	80
 
-const char *get_hostname();
-const char *get_sysname();
-const char *get_sysrelease();
+const char *get_hostname(void);
+const char *get_sysname(void);
+const char *get_sysrelease(void);
 
 #ifndef min
 # define min(a,b) (((a) < (b)) ? (a) : (b))
diff --git a/clients/lcdproc/mode.c b/clients/lcdproc/mode.c
index 8b17420..759ca8f 100644
--- a/clients/lcdproc/mode.c
+++ b/clients/lcdproc/mode.c
@@ -27,7 +27,7 @@
 
 
 int
-mode_init()
+mode_init(void)
 {
 	machine_init();
 
@@ -35,7 +35,7 @@ mode_init()
 }
 
 void
-mode_close()
+mode_close(void)
 {
 	machine_close();
 }
diff --git a/clients/lcdproc/mode.h b/clients/lcdproc/mode.h
index b46e2f5..5387add 100644
--- a/clients/lcdproc/mode.h
+++ b/clients/lcdproc/mode.h
@@ -4,8 +4,8 @@
 #include "main.h"
 
 
-int mode_init();
-void mode_close();
+int mode_init(void);
+void mode_close(void);
 
 int update_screen(mode * m, int display);