first pass

[PuTTY.git] / unix / uxsel.c

diff --git a/unix/uxsel.c b/unix/uxsel.c
index fa48507fced4a0590fa557a192d411c9c6888fca..ef25cdb574e2a6cf7fe4bb95112be1e05e52b947 100644 (file)
--- a/unix/uxsel.c
+++ b/unix/uxsel.c
@@ -64,6 +64,8 @@ void uxsel_set(int fd, int rwx, uxsel_callback_fn callback)
 {
     struct fd *newfd;
 
+    assert(fd >= 0);
+
     uxsel_del(fd);
 
     if (rwx) {