Using multi-step processing in message processing

A response module identifier and a response flag are included in a message structure. When a sending module needs to transfer a message to a receiving module for processing, the response module identifier of the message is used to store the sending module's handle, and the response flag is set to indicate that the sending module is going to wait for the message to be completely processed by a receiving module. The operating system routes the message to the receiving module, where the receiving module determines if the message needs to be processed by multi-step processing. If so, it divides the message into a plurality of messages, the response module identifier of each storing the receiving module's handle. All these messages are caught and transferred to the receiving module for processing themselves, and the response flag is reset after the last such message is processed. Once processing is complete, the receiving module transfers a response message to the sending module using the response module identifier of the original message.