diff --git a/library/platform_util.c b/library/platform_util.c
index 694e23a..17913b4 100644
--- a/library/platform_util.c
+++ b/library/platform_util.c
@@ -141,7 +141,7 @@
         return 0;
     }
 
-    return -1;
+    return MBEDTLS_ERR_PLATFORM_ALLOC_FAILED;
 }
 
 int mbedtls_platform_memcmp( const void *buf1, const void *buf2, size_t num )