1 files changed, 6 insertions, 4 deletions
diff --git a/src/thirdparty/unrar/strfn.cpp b/src/thirdparty/unrar/strfn.cpp
index c2888a09c..f83482fb2 100644
--- a/src/thirdparty/unrar/strfn.cpp
+++ b/src/thirdparty/unrar/strfn.cpp
@@ -265,8 +265,9 @@ wchar* wcsncpyz(wchar *dest, const wchar *src, size_t maxlen)
 char* strncatz(char* dest, const char* src, size_t maxlen)
 {
   size_t Length = strlen(dest);
-  if (Length + 1 < maxlen)
-    strncat(dest, src, maxlen - Length - 1);
+  int avail=int(maxlen - Length - 1);
+  if (avail > 0)
+    strncat(dest, src, avail);
   return dest;
 }
 
@@ -277,8 +278,9 @@ char* strncatz(char* dest, const char* src, size_t maxlen)
 wchar* wcsncatz(wchar* dest, const wchar* src, size_t maxlen)
 {
   size_t Length = wcslen(dest);
-  if (Length + 1 < maxlen)
-    wcsncat(dest, src, maxlen - Length - 1);
+  int avail=int(maxlen - Length - 1);
+  if (avail > 0)
+    wcsncat(dest, src, avail);
   return dest;
 }