From 3da8c2850d6589b9fa387ab2a2c87355d1224b1e Mon Sep 17 00:00:00 2001
From: Sergey Poznyakoff <gray@gnu.org>
Date: Mon, 14 Jan 2019 13:59:39 +0200
Subject: [PATCH 49/58] Fix iconv usage.

Patch by Christian Weisgerber.

* src/utf8.c (utf8_convert): non-zero return from iconv means failure.
---
 src/utf8.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/utf8.c b/src/utf8.c
index 95a016d..91476aa 100644
--- a/src/utf8.c
+++ b/src/utf8.c
@@ -81,7 +81,18 @@ utf8_convert (bool to_utf, char const *input, char **output)
   outlen = inlen * MB_LEN_MAX + 1;
   ob = ret = xmalloc (outlen);
   ib = (char ICONV_CONST *) input;
-  if (iconv (cd, &ib, &inlen, &ob, &outlen) == -1)
+  /* According to POSIX, "if iconv() encounters a character in the input
+     buffer that is valid, but for which an identical character does not
+     exist in the target codeset, iconv() shall perform an
+     implementation-defined conversion on this character." It will "update
+     the variables pointed to by the arguments to reflect the extent of the
+     conversion and return the number of non-identical conversions performed".
+     On error, it returns -1. 
+     In other words, non-zero return always indicates failure, either because
+     the input was not fully converted, or because it was converted in a
+     non-reversible way.
+   */
+  if (iconv (cd, &ib, &inlen, &ob, &outlen) != 0)
     {
       free (ret);
       return false;
-- 
2.19.1

