From f8a609e7d568759280b5254ae638fac7fe4071db Mon Sep 17 00:00:00 2001
From: Vadim Penzin <vadim@penzin.net>
Date: Sun, 8 Jan 2017 07:26:00 +0200
Subject: [PATCH] Check whether dlerror(3) returns NULL.

---
 src/c/ffi/libraries.d | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/c/ffi/libraries.d b/src/c/ffi/libraries.d
index a39f20129..b95bcf9b2 100644
--- a/src/c/ffi/libraries.d
+++ b/src/c/ffi/libraries.d
@@ -147,7 +147,10 @@ set_library_error(cl_object block) {
   cl_object output;
   ecl_disable_interrupts();
 #ifdef HAVE_DLFCN_H
-  output = make_base_string_copy(dlerror());
+  {
+    const char * const error = dlerror ();
+    output = error == NULL ? ECL_NIL : make_base_string_copy(error);
+  }
 #endif
 #ifdef HAVE_MACH_O_DYLD_H
   {