Date: Tue, 27 Jun 2023 09:41:02 +0100
From: "Geoff Clare via austin-group-l at The Open Group"
<austin-group-l@opengroup.org>
Message-ID: <ZJqgnkTO1n2erQin@localhost>
| Yes, via XCU 1.1.2; the C standard allows it for signed long, so it's
| allowed for anything that 1.1.2 requires to be "equivalent to the
| ISO C standard signed long data type".
And of course, that means that even though the >> operator is in Table 1-2
as one that must be supported, it cannot actually work, as >> is unspecified
(or even undefined, I forget) on signed values, and POSIX sh arithmetic only
allows for signed values. << may have similar issues (at least some compilers
are starting to complain about the use of << with a signed left operand, which
I am guessing means at least some version of the C standard has made that be
unspecified/undefined as well).
The implementation I work with ignores that, and when an operation works
better with unsigned operands, it simply treats them as unsigned instead
of signed. I suspect other shells might do the same.
kre
