[cpp-threads] infinite loops

[Nick Maclaren]

I have been largely out of action for quite a while, but unfortunately
this point still remains relevant :-(

The infinite thread issue is VERY closely related to the Decimal
QUESTION I tried to ask at Berlin - i.e. does the proposal assume
that IEEE 754 flags will need to be supported?

The point is that they are an alternate, NON-memory, program-visible
state (with somewhat different rules), and synchronising them with
memory is tricky enough even when threads are not involved.

The simplistic answer that there is a separate copy for each thread
means that we are forever excluding any form of implicit threading
(as favoured by Bjarne), because we can no longer split two independent
actions (as the flags make them dependent).

And using floating-point (of ANY base) to emulate fixed-point
with overflow detection REQUIRES the inexact flag to be both
supported and raise an exception.  Which, in turn, is a disaster
for scientific computation, but that is another matter.

Note that there is no 'right' answer, but the question needs answering
as it affects threading.

To repeat:  this has NOTHING to do with decimal bases as such, but
is to do with what decimal floating-point is wanted for.  The same
would apply for binary, if accountants used binary.


Regards,
Nick Maclaren,
University of Cambridge Computing Service,
New Museums Site, Pembroke Street, Cambridge CB2 3QH, England.
Email:  nmm1 at cam.ac.uk
Tel.:  +44 1223 334761    Fax:  +44 1223 334679