From 70ba7a6e623a87723e61eb2899d3d92800336022 Mon Sep 17 00:00:00 2001
From: Connor Lane Smith <cls@lubutu.com>
Date: Fri, 10 Jun 2011 04:36:40 +0100
Subject: [PATCH] cksum: error check

---
 cksum.1 | 3 +--
 cksum.c | 5 +++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/cksum.1 b/cksum.1
index b7ce80b..432557f 100644
--- a/cksum.1
+++ b/cksum.1
@@ -6,5 +6,4 @@ cksum \- print file checksums
 .RI [ file ...]
 .SH DESCRIPTION
 .B cksum
-calculates and prints a cyclic redundancy check (CRC) for each input file, along
-with its size and name.
+calculates and prints a cyclic redundancy check (CRC) for each input file.
diff --git a/cksum.c b/cksum.c
index a274f6c..482ab25 100644
--- a/cksum.c
+++ b/cksum.c
@@ -88,9 +88,10 @@ cksum(FILE *fp, const char *s)
 		ck = (ck << 8) ^ crctab[(ck >> 24) ^ c];
 	for(i = n; i > 0; i >>= 8)
 		ck = (ck << 8) ^ crctab[(ck >> 24) ^ (i & 0377)];
-	ck = ~ck;
+	if(ferror(fp))
+		eprintf("%s: read error:", s ? s : "<stdin>");
 
-	printf("%lu %lu", ck, n);
+	printf("%lu %lu", ~ck, n);
 	if(s != NULL)
 		printf(" %s", s);
 	putchar('\n');