diff --git a/include/mbedtls/ssl_cache.h b/include/mbedtls/ssl_cache.h
index 7009827..08f98b5 100644
--- a/include/mbedtls/ssl_cache.h
+++ b/include/mbedtls/ssl_cache.h
@@ -105,7 +105,8 @@
  *
  * \return                \c 0 on success.
  * \return                #MBEDTLS_ERR_SSL_CACHE_ENTRY_NOT_FOUND if there is
- *                        no cache entry with specified session ID found.
+ *                        no cache entry with specified session ID found, or
+ *                        any other negative error code for other failures.
  */
 int mbedtls_ssl_cache_get(void *data,
                           unsigned char const *session_id,