Improve document for chk_buf_read_ptr
@@ -414,7 +414,9 @@ static inline int mbedtls_ssl_chk_buf_ptr( const uint8_t *cur,
* greater or equal than a needed length. If it is not the case, it
* returns #MBEDTLS_ERR_SSL_DECODE_ERROR error and pends a
* #MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR alert message.
- * It is used to guaranteed remaining length.
+ *
+ * This is a function-like macro. It is guaranteed to evaluate each
+ * argument exactly once.
*
* \param cur Pointer to the current position in the buffer.
* \param end Pointer to one past the end of the buffer.
