diff --git a/include/frnetlib/NetworkEncoding.h b/include/frnetlib/NetworkEncoding.h
index 9e55160..99d44c0 100644
--- a/include/frnetlib/NetworkEncoding.h
+++ b/include/frnetlib/NetworkEncoding.h
@@ -49,8 +49,8 @@
 
 #if defined(__GNUC__)
 #  if __BYTE_ORDER == __LITTLE_ENDIAN
-#   define htonll(x) __bswap_64 (x)
-#   define ntohll(x) __bswap_64 (x)
+#   define htonll(x) __builtin_bswap64 (x)
+#   define ntohll(x) __builtin_bswap64 (x)
 #  else
 #   define htonll(x) (x)
 #   define ntohll(x) (x)