WG15 Defect Report Ref: 9945-1-amd1-07
Topic: sigaction


This is an approved interpretation of 9945-1-amd1-1993.

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Last update: 1997-05-20


								9945-1-amd1-93  #7

 _____________________________________________________________________________

	Topic:                sigaction
	Relevant Sections:    3.3.4.2. Page 72 lines 915-923

Defect Report:
-----------------------

	From: ajosey@xopen.org (Andrew Josey)
	Date: Thu Mar  7 15:18:23 GMT 1996

(This request raised on Behalf of the X/Open Base working group)

ISO/IEC 9945-1-amd1-1993 	Section 3.3.4.2. Page 72 lines 915-923
describes what happens if a signal is pending that
is dispatched at a time when a signal handler was in place 
expecting three arguments.

This section does not describe what happens to the second and
third arguments of a signal handler that catches a signal
that was dispatched when a signal handler expecting one argument
was installed. What is the conformant behaviour in this case?

Interpretation response
------------------------

The question as asked has some ambiguity and would have different answers based
up which question is meant

If a signal is generated during a time that SA_SIGINFO is set in sa_flags,
sigqueue can pass a si_value and the signal has an associated si_code.  If
sigaction is called with sa_flags clear, then the standard is clear that 'the
signal-catching function shall be invoked with only a single argument' (pg 72
line 917): the signo is delivered.

If a signal is generated during a time that SA_SIGINFO is cleared in sa_flags,
sigqueue still has a si_value and the associated si_code.  If sigaction is then
called before delivery with sa_flags set, then the standard is clear that 'The
application specified value shall be passed to the signal-catching function...'
(pg 72 line 922-923).   


Rationale
-------------
None.
Forwarded to Interpretations group: Mar 7 1996
Finalised: Apr 9 1996