1 files changed, 2 insertions, 0 deletions
diff --git a/programmer.h b/programmer.h
index 303fbc4..51b9c40 100644
--- a/programmer.h
+++ b/programmer.h
@@ -636,8 +636,10 @@ void serprog_delay(int usecs);
 /* serial.c */
 #ifdef _WIN32
 typedef HANDLE fdtype;
+#define SER_INV_FD	INVALID_HANDLE_VALUE
 #else
 typedef int fdtype;
+#define SER_INV_FD	-1
 #endif
 
 void sp_flush_incoming(void);