Re: cvs commit: src/lib/libc/sys tls.2
:
:On Mon, 21 Mar 2005 11:15:32 -0800 (PST)
:Matthew Dillon <dillon@apollo.backplane.com> wrote:
:
:> Grumble (Matt goes off in a corner and mumbles about stupid standards
:> which use unsigned ints because some bozo wanted to write 2.1GB of data
:> in one go, when they really ought to just use normal ints).
:
:Why ought they do that?
:
:(or: why would one ever want a *negative* infosize?!)
:
:-Chris
It's not that, it's the same issue with sizeof() returning unsigned
when it really just ought to return an int. Unsigned quantities change
the way expressions in code are handled in ways that are not always
apparent. For example, if you are doing a delta calculation you can't
just do the calculation and check to see if the result is negative,
instead you have to do a range check before you do the calculation.
Things like that. Negative numbers are also very useful as a means of
representing out of band data or conditions. EOF == -1 is a good example.
Another is the handling of an optional argument. If 0 is an allowed
value then you can initialize an option to -1 to indicate that it has
not been issued. so, e.g. an optional 'int size_opt' argument, instead
of 'int size; int size_opt_is_valid;'. But with size_t you then have
to cast it to an unsigned. It just makes life unnecessarily difficult
when 99.9999% of the calls to all these routines never need to specify
huge blocks.
In the case of a memory block, I suppose 'long' would be a better choice
then 'int', but I really hate the way the hidden unsignedness of size_t
and sizeof() has infiltrated the standards.
-Matt
Matthew Dillon
<dillon@backplane.com>
討論串 (同標題文章)
完整討論串 (本文為第 6 之 20 篇)：