diff --git a/include/mruby.h b/include/mruby.h
index 33a15de0ef..29d13c553f 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -239,9 +239,10 @@ mrb_sym mrb_intern(mrb_state *mrb,const char *cstr)
   return mrb_intern_cstr(mrb, cstr);
 }
 
-void *mrb_malloc(mrb_state*, size_t);
-void *mrb_calloc(mrb_state*, size_t, size_t);
-void *mrb_realloc(mrb_state*, void*, size_t);
+void *mrb_malloc(mrb_state*, size_t);         /* raise RuntimeError if no mem */
+void *mrb_calloc(mrb_state*, size_t, size_t); /* ditto */
+void *mrb_realloc(mrb_state*, void*, size_t); /* ditto */
+void *mrb_malloc_simple(mrb_state*, size_t);  /* return NULL if no memory available */
 struct RBasic *mrb_obj_alloc(mrb_state*, enum mrb_vtype, struct RClass*);
 void mrb_free(mrb_state*, void*);
 
diff --git a/src/gc.c b/src/gc.c
index 3e33c052c6..7eee61dc1e 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -182,6 +182,19 @@ mrb_malloc(mrb_state *mrb, size_t len)
   return mrb_realloc(mrb, 0, len);
 }
 
+void*
+mrb_malloc_simple(mrb_state *mrb, size_t len)
+{
+  void *p2;
+
+  p2 = (mrb->allocf)(mrb, 0, len, mrb->ud);
+  if (!p2 && len > 0 && mrb->heaps) {
+    mrb_garbage_collect(mrb);
+    p2 = (mrb->allocf)(mrb, 0, len, mrb->ud);
+  }
+  return p2;
+}
+
 void*
 mrb_calloc(mrb_state *mrb, size_t nelem, size_t len)
 {