diff -r 6342cbbd1922 -r e19825a1430a test/mpool_tests.c
--- a/test/mpool_tests.c	Wed Oct 18 12:03:44 2017 +0200
+++ b/test/mpool_tests.c	Wed Oct 18 14:23:57 2017 +0200
@@ -123,7 +123,10 @@
     ucx_mempool_destroy(pool);
 }
 
-UCX_EXTERN void test_setdestr(void* elem) {
+#ifdef __cplusplus
+extern "C"
+#endif
+void test_setdestr(void* elem) {
     intptr_t *cb = (intptr_t*) ((intptr_t*) elem)[1];
     *cb = 42;
 }