diff --git a/src/modbus-tcp.c b/src/modbus-tcp.c
index b084532..081ceee 100644
--- a/src/modbus-tcp.c
+++ b/src/modbus-tcp.c
@@ -30,6 +30,7 @@
 # include <ws2tcpip.h>
 # define SHUT_RDWR 2
 # define close closesocket
+# define strdup _strdup
 #else
 # include <sys/socket.h>
 # include <sys/ioctl.h>