Open System Services System Calls Reference Manual (G06.28+, H06.05+)

System Functions (f - i) getsockopt(2)
STANDARDS CONFORMANCE
The HP implementation does not:
Implement the SO_LINGER option for AF_UNIX sockets.
Return the errno value [ENOSR].
The following are HP extensions to the XPG4 specication:
The errno value [ECONNRESET] can be returned when the transport provider process
is unavailable.
The SO_REUSEPORT option is supported.
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