diff --git a/src/modbus-data.c b/src/modbus-data.c
index bbcbab870..f889e2d17 100644
--- a/src/modbus-data.c
+++ b/src/modbus-data.c
@@ -47,6 +47,7 @@
 # define bswap_16 _byteswap_ushort
 #endif
 
+#if !defined(__CYGWIN__)
 #if !defined(bswap_16)
 #   warning "Fallback on C functions for bswap_16"
 static inline uint16_t bswap_16(uint16_t x)
@@ -54,6 +55,7 @@ static inline uint16_t bswap_16(uint16_t x)
     return (x >> 8) | (x << 8);
 }
 #endif
+#endif
 
 #if !defined(bswap_32)
 #   warning "Fallback on C functions for bswap_32"