Final answer:
If a server crashes during a client's blocking read operation, the client will typically receive an error or EOF, indicating the loss of connection due to the server failure. Robust error-handling on the client side is crucial to handle such situations.
Step-by-step explanation:
When a server crashes while a client is blocking in the read() operation after writing some data, the outcome depends on various factors, including the networking protocols in use and the server's configuration. In general, if the server application crashes and if the underlying operating system supports robust socket handling, it should close all open sockets associated with it. Consequently, the client's blocked read() call will typically return with an error indicating that the connection has been lost or reset.
For TCP connections, this may result in the client receiving an EOF (End-of-File) marker or a socket error indicating that the connection has been forcibly closed. However, without a proper error-handling mechanism on the client side, this situation could potentially lead to the client application hanging or failing. Therefore, it's crucial for developers to implement robust error-handling routines to deal with such network anomalies, ensuring that client applications can adequately respond to a sudden server failure.