From 6b073cda9ed996cec5895eb2d9f0b0fd88e50312 Mon Sep 17 00:00:00 2001
From: Mischa POSLAWSKY <perl@shiar.org>
Date: Thu, 5 Sep 2019 00:50:04 +0200
Subject: [PATCH] disable markers without graph

Avoid error "Modification of non-creatable array value attempted"
trying to access unallocated positions.
---
 graph | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/graph b/graph
index b41f0c0..0d9db2e 100755
--- a/graph
+++ b/graph
@@ -39,7 +39,7 @@ my $size   = ($maxval - $minval) &&
 	($opt{width} - $lenval - $len) / ($maxval - $minval);  # bar multiplication
 
 my @barmark;
-if ($opt{markers} // 1) {
+if ($opt{markers} // 1 and $size > 0) {
 	sub orderpos { (($order[$_[0]] + $order[$_[0] + .5]) / 2 - $minval) * $size }
 	$barmark[ (sum(@order) / @order - $minval) * $size ] = '=';  # average
 	$barmark[ orderpos($#order / 2) ] = '+';  # mean
-- 
2.30.0