diff --git a/iguana/exchanges/LP_socket.c b/iguana/exchanges/LP_socket.c
index a9a5e6b2c..1e4e9ec2e 100644
--- a/iguana/exchanges/LP_socket.c
+++ b/iguana/exchanges/LP_socket.c
@@ -25,6 +25,7 @@
 #define WIN32_LEAN_AND_MEAN
 #include <WinSock2.h>
 #endif
+#include <fcntl.h>
 
 int32_t set_blocking_mode(int32_t sock,int32_t is_blocking) // from https://stackoverflow.com/questions/2149798/how-to-reset-a-socket-back-to-blocking-mode-after-i-set-it-to-nonblocking-mode?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa
 {