This section discusses each and common variations where appropriate. System calls interrupt when a signal is delivered. In many cases the default action is to ignore the signal, causing the signal to be lost. In the worst case the default action is to terminate the process. Additionally any signal can interrupt a system call.
Few applications attempt to restart system calls that have been interrupted by a signal.
This results in even more unreliability. Wait for a signal to arrive. Take the default action for this signal. Ignore this signal. Signal handlers normally remain installed during and after signal delivery.