diff --git a/sim_sock.c b/sim_sock.c
index 858a74b6..4235cea0 100644
--- a/sim_sock.c
+++ b/sim_sock.c
@@ -1045,7 +1045,7 @@ int keepalive = 1;
     defined (__APPLE__) || defined (__OpenBSD__) || \
     defined(__NetBSD__) || defined(__FreeBSD__) || \
     (defined(__hpux) && defined(_XOPEN_SOURCE_EXTENDED)) || \
-    defined (__HAIKU__)
+    defined (__HAIKU__) || defined(__CYGWIN__)
 socklen_t size;
 #elif defined (_WIN32) || defined (__EMX__) || \
      (defined (__ALPHA) && defined (__unix__)) || \
@@ -1111,7 +1111,7 @@ struct sockaddr_storage peername;
     defined (__APPLE__) || defined (__OpenBSD__) || \
     defined(__NetBSD__) || defined(__FreeBSD__) || \
     (defined(__hpux) && defined(_XOPEN_SOURCE_EXTENDED)) || \
-    defined (__HAIKU__)
+    defined (__HAIKU__) || defined(__CYGWIN__)
 socklen_t peernamesize = (socklen_t)sizeof(peername);
 #elif defined (_WIN32) || defined (__EMX__) || \
      (defined (__ALPHA) && defined (__unix__)) || \
@@ -1147,7 +1147,7 @@ static int _sim_getaddrname (struct sockaddr *addr, size_t addrsize, char *hostn
     defined (__APPLE__) || defined (__OpenBSD__) || \
     defined(__NetBSD__) || defined(__FreeBSD__) || \
     (defined(__hpux) && defined(_XOPEN_SOURCE_EXTENDED)) || \
-    defined (__HAIKU__)
+    defined (__HAIKU__) || defined(__CYGWIN__)
 socklen_t size = (socklen_t)addrsize;
 #elif defined (_WIN32) || defined (__EMX__) || \
      (defined (__ALPHA) && defined (__unix__)) || \
@@ -1181,7 +1181,7 @@ struct sockaddr_storage sockname, peername;
     defined (__APPLE__) || defined (__OpenBSD__) || \
     defined(__NetBSD__) || defined(__FreeBSD__) || \
     (defined(__hpux) && defined(_XOPEN_SOURCE_EXTENDED)) || \
-    defined (__HAIKU__)
+    defined (__HAIKU__) || defined(__CYGWIN__)
 socklen_t socknamesize = (socklen_t)sizeof(sockname);
 socklen_t peernamesize = (socklen_t)sizeof(peername);
 #elif defined (_WIN32) || defined (__EMX__) || \