Informs the stream head that the user wishes the kernel to issue the SIGPOLL signal when a particular event occurs on the stream.
The I_SETSIG operation informs the stream head that the user wishes the kernel to issue the SIGPOLL signal (see the signal and sigset subroutines) when a particular event has occurred on the stream associated with the fildes parameter. The I_SETSIG operation supports an asynchronous processing capability in STREAMS. The value of the arg parameter is a bit mask that specifies the events for which the user should be signaled. It is the bitwise-OR of any combination of the following constants:
A user process may choose to be signaled only by priority messages by setting the arg bit mask to the value S_HIRPI.
Processes that wish to receive SIGPOLL signals must explicitly register to receive them using I_SETSIG. If several processes register to receive this signal for the same event on the same stream, each process will be signaled when the event occurs.
If the value of the arg parameter is 0, the calling process is unregistered and does not receive further SIGPOLL signals.
If unsuccessful, the errno global variable is set to one of the following values:
This operation is part of STREAMS Kernel Extensions.
The poll subroutine, signal subroutine.
The streamio operations.
The I_GETSIG streamio operation.
Understanding STREAMS Monitoring in AIX Version 4.3 Communications Programming Concepts.