From 06cafadf4f3e9d85efd6f1b4b4e7c4387ce650cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dan=20=C4=8Cerm=C3=A1k?= <dan.cermak@cgc-instruments.com>
Date: Sun, 5 Nov 2017 23:31:31 +0100
Subject: [PATCH] Added assertion that call to vsnprintf succeeds

---
 src/image.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/image.cpp b/src/image.cpp
index 338720fc..701cc81d 100644
--- a/src/image.cpp
+++ b/src/image.cpp
@@ -1004,6 +1004,7 @@ namespace Exiv2 {
             va_start(args, format);                        // args start after format
             rc = vsnprintf(&buffer[0], buffer.size(), format, args);
             va_end(args);                                  // free the args
+            assert(rc >= 0);                               // rc < 0 => we have made an error in the format string
             if ( rc > 0 )
                 need = static_cast<size_t>(rc);
         } while ( buffer.size() <= need );