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

signal(4) OSS System Calls Reference Manual
STANDARDS CONFORMANCE
The HP implementation does not provide the following signals de
fined in the XPG4 Version 2
specification:
• SIGBUS, SIGPOLL, SIGPROF, SIGSYS, SIGTRAP, SIGVTALRM, SIGXCPU, and
SIGXFSZ.
The POSIX standards leave some features to the implementing vendor to define. The following
features are affected in the HP implementation:
• HP-specific signals are supported; see the extensions listed later.
• The _POSIX_JOB_CONTROL symbolic constant is always defined. Hence, the job
control signals are all supported: SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP,
SIGTTIN, and SIGTTOU.
• On generation of a blocked signal, it is unspecified whether the signal is discarded or
remains pending when the associated action is to ignore the signal.
• Only one instance of the same signal can remain pending for a process. Subsequent
occurrences of the same signal are discarded. However, this action is likely to change in
a future release, so users should not depend on it.
• The order in which pending signals are delivered to a process is unspecified and should
not be relied upon.
• Signals are generated for all operating system trap conditions normally detectable in the
Guardian environment.
• After ignoring a SIGFPE, SIGILL, SIGLIMIT, SIGMEMERR, SIGMEMMGR,
SIGNOMEM, SIGSEGV,orSIGSTK signal that was not generated by a kill() or
raise() function, a process terminates. Similarly, after returning from a signal-catching
function for one occurrence of such a signal, a process receives a SIGABEND signal and
terminates with a Guardian condition code of -11. A process deletion (-101) Guardian
system message is sent to the mom, ancestor, or job ancestor of the terminated process
and indicates abnormal termination.
• No SIGCHLD signal is generated if a process establishes a signal-catching function for
the SIGCHLD signal while the process has a terminated child process for which it has
not waited.
The following are HP extensions to the XPG4 Version 2 specification:
• The following signals are HP extensions: SIGABEND, SIGIO, SIGLIMIT, SIGME-
MERR, SIGMEMMGR, SIGNOMEM, SIGRECV, SIGSTK, SIGTIMEOUT,
SIGWINCH, and SIGUNCP.
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