From 571c601b66ee893483617d8a6b47b923c99361c5 Mon Sep 17 00:00:00 2001
From: Stephen Heumann <stephenheumann@gmail.com>
Date: Sun, 9 Jun 2019 19:12:51 -0500
Subject: [PATCH] strtoul: return 0 when given an empty string, as required by
 the C standards.

The issue was introduced in commit 6e9790667.

errno is now set to EINVAL in this case. (This is not required by the C standards, but is consistent with various other implementations.)

This fixes the cases in #23 related to strtol() and strtoul().
---
 stdlib.asm | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/stdlib.asm b/stdlib.asm
index 9d3b212..91f94ba 100644
--- a/stdlib.asm
+++ b/stdlib.asm
@@ -926,6 +926,9 @@ cn4      inc4  str                      next char
 
 cn5      lda   foundOne                 if no digits were found, flag the error
          bne   rt1
+         lda   #EINVAL
+         sta   >errno
+         bra   rt2
 ;
 ;  flag an error
 ;