Open System Services System Calls Reference Manual (G06.25+, H06.03+)

System Functions (s and S) sigaction(2)
Files: signal(4).
STANDARDS CONFORMANCE
The POSIX standards leave some features to the implementing vendor to define. The following
features are affected in the HP implementation:
• The ordering of members within the sigaction structure might not match the ordering
used in signal.h header files in other environments or on other systems.
• The values returned in the fields of the structure pointed to by the o_action parameter
when sigaction() is called and the previous action for the specified signal was esta-
blished by the signal() function are unspecified in the POSIX.1 standard. These values
should therefore not be depended upon other than to pass the address returned in
o_action as the action parameter to another sigaction() function; the result is as if the
signal() function were repeated.
• The action is ignored when the action is set to the SIG_DFL value for a signal that can-
not be caught or ignored.
The following are HP extensions to the XPG4 Version 2 specification:
• HP has defined several new signals, including SIGABEND. See the signal(4) reference
page for a complete list.
• The [ENOTOSS] error value is an HP extension.
• The spthread.h header file is an HP extension and an HP exception to the IEEE Std
1003.1c-1995, POSIX System Application Program Interface.
HP does not define members of the sigaction structure following sa_flags.
HP does not define the SA_SIGINFO symbolic constant.
HP does not support the Realtime Signals Extension. The errno value [ENOTSUP] is not
returned.
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