--- xoscope-2.0/proscope.c
+++ xoscope-2.0/proscope.c
@@ -11,6 +11,7 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include "proscope.h"
 #include "oscope.h"
--- xoscope-2.0/oscope.c
+++ xoscope-2.0/oscope.c
@@ -408,7 +408,15 @@
    */
 
   displayed_samples = p->signal ? samples(p->signal->rate) : 0;
-  max_samples = p->signal ? max(samples(p->signal->rate), p->signal->num) : 0;
+  if ( p->signal ) {
+    if ( samples(p->signal->rate) > p->signal->num ) {
+      max_samples = samples(p->signal->rate);
+    } else {
+      max_samples = p->signal->num;
+    }
+  } else {
+    max_samples = 0;
+  }
 
   if (c >= 'A' && c <= 'Z') {
     if (p->signal) {