diff --git a/lib/roken/roken.h.in b/lib/roken/roken.h.in
index e36b25f45..219b08775 100644
--- a/lib/roken/roken.h.in
+++ b/lib/roken/roken.h.in
@@ -68,7 +68,8 @@ typedef SOCKET rk_socket_t;
 #define rk_IS_BAD_SOCKET(s) ((s) == INVALID_SOCKET)
 #define rk_IS_SOCKET_ERROR(rv) ((rv) == SOCKET_ERROR)
 #define rk_SOCK_ERRNO WSAGetLastError()
-#define rk_SOCK_IOCTL(s,c,a) ioctlsocket((s),(c),(a))
+
+ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL rk_SOCK_IOCTL(SOCKET s, long cmd, int * argp);
 
 #define ETIMEDOUT               WSAETIMEDOUT
 #define EWOULDBLOCK             WSAEWOULDBLOCK
diff --git a/lib/roken/socket.c b/lib/roken/socket.c
index bd800ac5a..ef594ffd0 100644
--- a/lib/roken/socket.c
+++ b/lib/roken/socket.c
@@ -316,6 +316,19 @@ socket_to_fd(rk_socket_t sock, int flags)
 #endif
 }
 
+#ifdef HAVE_WINSOCK
+ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
+rk_SOCK_IOCTL(SOCKET s, long cmd, int * argp) {
+    u_long ul = (argp)? *argp : 0;
+    int rv;
+
+    rv = ioctlsocket(s, cmd, &ul);
+    if (argp)
+	*argp = (int) ul;
+    return rv;
+}
+#endif
+
 #ifndef HEIMDAL_SMALLER
 #undef socket