diff --git a/libc/include/isc/heap.h b/libc/include/isc/heap.h
new file mode 100644
index 0000000..ea5a6e9
--- /dev/null
+++ b/libc/include/isc/heap.h
@@ -0,0 +1,49 @@
+/*	$NetBSD: heap.h,v 1.1.1.1 2004/05/20 19:49:41 christos Exp $	*/
+
+/*
+ * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (c) 1997,1999 by Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and 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 ISC DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
+ */
+
+typedef int (*heap_higher_priority_func)(void *, void *);
+typedef void (*heap_index_func)(void *, int);
+typedef void (*heap_for_each_func)(void *, void *);
+
+typedef struct heap_context {
+	int array_size;
+	int array_size_increment;
+	int heap_size;
+	void **heap;
+	heap_higher_priority_func higher_priority;
+	heap_index_func index;
+} *heap_context;
+
+#define heap_new	__heap_new
+#define heap_free	__heap_free
+#define heap_insert	__heap_insert
+#define heap_delete	__heap_delete
+#define heap_increased	__heap_increased
+#define heap_decreased	__heap_decreased
+#define heap_element	__heap_element
+#define heap_for_each	__heap_for_each
+
+heap_context	heap_new(heap_higher_priority_func, heap_index_func, int);
+int		heap_free(heap_context);
+int		heap_insert(heap_context, void *);
+int		heap_delete(heap_context, int);
+int		heap_increased(heap_context, int);
+int		heap_decreased(heap_context, int);
+void *		heap_element(heap_context, int);
+int		heap_for_each(heap_context, heap_for_each_func, void *);