- source_basename = base_name (source);
- dest_basename = base_name (dest);
- source_baselen = base_len (source_basename);
- dest_baselen = base_len (dest_basename);
- if (source_baselen == dest_baselen
- && memcmp (source_basename, dest_basename, dest_baselen) == 0)
+ char const *source_basename = base_name (source);
+ char const *dest_basename = base_name (dest);
+ size_t source_baselen = base_len (source_basename);
+ size_t dest_baselen = base_len (dest_basename);
+ bool identical_basenames =
+ (source_baselen == dest_baselen
+ && memcmp (source_basename, dest_basename, dest_baselen) == 0);
+ bool compare_dirs = identical_basenames;
+ bool same = false;
+
+#if ! _POSIX_NO_TRUNC && HAVE_PATHCONF && defined _PC_NAME_MAX
+ /* This implementation silently truncates pathname components. If
+ the base names might be truncated, check whether the truncated
+ base names are the same, while checking the directories. */
+ size_t slen_max = HAVE_LONG_FILE_NAMES ? 255 : _POSIX_NAME_MAX;
+ size_t min_baselen = MIN (source_baselen, dest_baselen);
+ if (slen_max <= min_baselen
+ && memcmp (source_basename, dest_basename, slen_max) == 0)
+ compare_dirs = true;
+#endif
+
+ if (compare_dirs)