diff --git a/include/compiz.h b/include/compiz.h
index d50996f..b7e0e32 100644
--- a/include/compiz.h
+++ b/include/compiz.h
@@ -26,7 +26,7 @@
 #ifndef _COMPIZ_H
 #define _COMPIZ_H
 
-#define ABIVERSION 20070507
+#define ABIVERSION 20070524
 
 #include <stdio.h>
 #include <sys/time.h>
@@ -309,6 +309,15 @@ typedef enum {
     CompActionStateAutoGrab    = 1 << 11
 } CompActionState;
 
+typedef enum {
+    CompLogLevelFatal = 0,
+    CompLogLevelError,
+    CompLogLevelWarn,
+    CompLogLevelInfo,
+    CompLogLevelDebug
+
+} CompLogLevel;
+
 typedef struct _CompKeyBinding {
     int		 keycode;
     unsigned int modifiers;
@@ -728,6 +737,12 @@ typedef void (*MatchExpHandlerChangedProc) (CompDisplay *display);
 typedef void (*MatchPropertyChangedProc) (CompDisplay *display,
 					  CompWindow  *window);
 
+typedef void (*LogMessageProc) (CompDisplay  *d,
+				char         *componentName,
+				CompLogLevel level,
+				char         *format,
+				va_list      args);
+
 struct _CompDisplay {
     Display    *display;
     CompScreen *screens;
@@ -925,9 +940,12 @@ struct _CompDisplay {
     MatchExpHandlerChangedProc matchExpHandlerChanged;
     MatchPropertyChangedProc   matchPropertyChanged;
 
+    LogMessageProc logMessage;
+
     CompPrivate *privates;
 };
 
+
 extern CompDisplay *compDisplays;
 
 int
@@ -979,6 +997,12 @@ void
 fileWatchRemoved (CompDisplay   *display,
 		  CompFileWatch *fileWatch);
 
+void
+compLogMessage (CompDisplay *d, char *componentName, CompLogLevel level, char *format, ...);
+
+void
+logMessage (CompDisplay *d, char *componentName, CompLogLevel level, char *format, va_list args);
+
 int
 compCheckForError (Display *dpy);
 
diff --git a/src/display.c b/src/display.c
index 45ba4f0..616d8a3 100644
--- a/src/display.c
+++ b/src/display.c
@@ -2003,6 +2003,8 @@ addDisplay (char *name)
     d->matchExpHandlerChanged = matchExpHandlerChanged;
     d->matchPropertyChanged   = matchPropertyChanged;
 
+    d->logMessage = logMessage;
+
     d->supportedAtom	     = XInternAtom (dpy, "_NET_SUPPORTED", 0);
     d->supportingWmCheckAtom = XInternAtom (dpy, "_NET_SUPPORTING_WM_CHECK", 0);
 
diff --git a/src/main.c b/src/main.c
index 477e3d0..034196c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -120,6 +120,37 @@ usage (void)
 	    programName);
 }
 
+void
+compLogMessage (CompDisplay *d, char *componentName,
+		CompLogLevel level, char *format, ...)
+{
+    va_list args;
+
+    if (!d)
+	d = compDisplays;
+
+    va_start(args, format);
+
+    if (!d)
+	logMessage (d, componentName, level, format, args);
+    else
+	(*d->logMessage) (d, componentName, level, format, args);
+
+    va_end(args);
+}
+
+void
+logMessage (CompDisplay *d, char *componentName,
+	    CompLogLevel level, char *format, va_list args)
+{
+    char defaultMessage[1024];
+
+    snprintf (defaultMessage, 1024, "%s (%s): %s",
+	      programName, componentName, format);
+
+    vfprintf (stderr, defaultMessage, args);
+}
+
 static void
 signalHandler (int sig)
 {
@@ -227,6 +258,8 @@ main (int argc, char **argv)
     programArgc = argc;
     programArgv = argv;
 
+    compDisplays = NULL;
+
     signal (SIGHUP, signalHandler);
     signal (SIGCHLD, signalHandler);
     signal (SIGINT, signalHandler);
@@ -329,7 +362,8 @@ main (int argc, char **argv)
 	}
 	else if (*argv[i] == '-')
 	{
-	    fprintf (stderr, "%s: Unknown option '%s'\n", programName, argv[i]);
+	    compLogMessage (NULL, "core", CompLogLevelWarn,
+			    "Unknown option '%s'\n", argv[i]);
 	}
 	else
 	{