diff --git a/gnu/lib/libdialog/checklist.c b/gnu/lib/libdialog/checklist.c
index 0e8e419e2fa..bc6bcba21e0 100644
--- a/gnu/lib/libdialog/checklist.c
+++ b/gnu/lib/libdialog/checklist.c
@@ -214,7 +214,7 @@ draw:
 		}
 		delwin(save);
 	    }
-	    else {
+	    else if (result) {
 		*result = '\0';
 		for (i = 0; i < item_no; i++) {
 		    if (status[i]) {
diff --git a/gnu/lib/libdialog/menubox.c b/gnu/lib/libdialog/menubox.c
index cc582110fbd..ef945af0ae6 100644
--- a/gnu/lib/libdialog/menubox.c
+++ b/gnu/lib/libdialog/menubox.c
@@ -203,7 +203,7 @@ draw:
 		}
 		delwin(save);
 	    }
-	    else
+	    else if (result)
 		strcpy(result, items[(scroll + choice) * 2]);
 	    delwin(menu);
 	    delwin(dialog);
diff --git a/gnu/lib/libdialog/radiolist.c b/gnu/lib/libdialog/radiolist.c
index d368944790c..88fee25fd1c 100644
--- a/gnu/lib/libdialog/radiolist.c
+++ b/gnu/lib/libdialog/radiolist.c
@@ -222,7 +222,7 @@ draw:
 		}
 		delwin(save);
 	    }
-	    else {
+	    else if (result) {
 		*result = '\0';
 		for (i = 0; i < item_no; i++) {
 		    if (status[i]) {