From a5c415d15a5ca6d35c290bc2430dcb5e812cf2ce Mon Sep 17 00:00:00 2001
From: Ryan Culpepper <ryanc@racket-lang.org>
Date: Wed, 21 Nov 2012 00:01:35 -0500
Subject: [PATCH] change allocator wrapper to ignore #f results

Supports foreign functions that either allocate or return NULL
(translated to #f).
---
 collects/ffi/unsafe/alloc.rkt | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/collects/ffi/unsafe/alloc.rkt b/collects/ffi/unsafe/alloc.rkt
index 5b03678069..107e910b62 100644
--- a/collects/ffi/unsafe/alloc.rkt
+++ b/collects/ffi/unsafe/alloc.rkt
@@ -23,8 +23,9 @@
          start-atomic
          (lambda ()
            (let ([v (apply proc args)])
-             (hash-set! allocated v (list d))
-             (register-finalizer v deallocate)
+             (when v
+               (hash-set! allocated v (list d))
+               (register-finalizer v deallocate))
              v))
          end-atomic))
    proc))