--- a/dwm.c	Mon Mar 24 13:49:19 2008 +0000
+++ b/dwm.c	Mon Mar 24 14:23:28 2008 +0000
@@ -178,6 +178,7 @@
 void setclientstate(Client *c, long state);
 void setgeom(const char *arg);
 void setlayout(const char *arg);
+void setmfact(const char *arg);
 void setup(void);
 void spawn(const char *arg);
 void tag(const char *arg);
@@ -1463,6 +1464,26 @@
 }
 
 void
+setmfact(const char *arg) {
+	double delta;
+
+	if(!arg)
+		return;
+	delta = strtod(arg, NULL);
+	if(arg[0] == '-' || arg[0] == '+') {
+		if(mfact + delta < 0.1 || mfact + delta > 0.9)
+			return;
+		mfact += delta;
+	}
+	else {
+		if(delta < 0.1 || delta > 0.9)
+			return;
+		mfact = delta;
+	}
+	arrange();
+}
+
+void
 setup(void) {
 	unsigned int i, w;
 	XSetWindowAttributes wa;