Problems with signal handler

[Ronald S H Khoo]

allbery at ncoast.ORG (Brandon S. Allbery KB8JRR) writes:

> free list.)  (Actually, most modern Unixes allow signals to be "held", so that
> critical operations like this can complete before the signal trap executes.
> However, this is non-portable:  SVR3.2 does it differently from BSD4.3 does it
> differently from SunOS 4.x does it differently from ... you get the idea.  And
> you can't do it at all under Xenix or V7.

To pick a nit, SCO Xenix V.2.3 has sighold()/sigrelse().  Question:
where do these come from ? BSD 4.1 ?

Actually, what I'd really like to know is, is there an abstract interface to
"held" signals that maps reasonably well on top of all the seemingly
endless different kinds of signal interfaces ?  Or is it really the case
that all we can really use in half-portable code is just plain signal() ?

-- 
Ronald Khoo <ronald at robobar.co.uk> +44 81 991 1142 (O) +44 71 229 7741 (H)