Index: examples/gc_no_raii/pool-alloc/allocate-mmap.c
===================================================================
--- examples/gc_no_raii/pool-alloc/allocate-mmap.c	(revision 90152a4860529aff7214be01cd22abd37012cd19)
+++ examples/gc_no_raii/pool-alloc/allocate-mmap.c	(revision 90152a4860529aff7214be01cd22abd37012cd19)
@@ -0,0 +1,44 @@
+/*
+ * Allocation functions (mmap)
+ *
+ * Copyright (c) 2014, 2015 Gregor Richards
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+static void *allocPool(int mustSucceed)
+{
+    unsigned char *space, *aspace;
+    struct GGGGC_Pool *ret;
+
+    /* allocate enough space that we can align it later */
+    space = mmap(NULL, GGGGC_POOL_BYTES*2, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
+    if (space == NULL) {
+        if (mustSucceed) {
+            perror("mmap");
+            abort();
+        }
+        return NULL;
+    }
+
+    /* align it */
+    ret = GGGGC_POOL_OF(space + GGGGC_POOL_BYTES - 1);
+    aspace = (unsigned char *) ret;
+
+    /* free unused space */
+    if (aspace > space)
+        munmap(space, aspace - space);
+    munmap(aspace + GGGGC_POOL_BYTES, space + GGGGC_POOL_BYTES - aspace);
+
+    return ret;
+}