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Re: Why is glibc not extensive?

From Kaz Kylheku <864-117-4973@kylheku.com>
Newsgroups comp.lang.c
Subject Re: Why is glibc not extensive?
Date 2022-11-27 13:05 +0000
Organization A noiseless patient Spider
Message-ID <20221127045152.541@kylheku.com> (permalink)
References (5 earlier) <tl7sm7$2uat7$1@dont-email.me> <c9a90f81-5fa8-4157-8901-e7510da1019cn@googlegroups.com> <a81ebdfc-4087-496a-9b21-3e321e37156an@googlegroups.com> <867czh8x01.fsf@linuxsc.com> <de182215-be2a-46c7-868e-7759bee60635n@googlegroups.com>

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On 2022-11-27, Michael S <already5chosen@yahoo.com> wrote:
> If current rate of Moore Law is not improved then even with
> all conservatism of standard bodies it will happen several 
> decades before the first individual object reaches 2**63-1.

Currently, people are using the top bits of 64 bit pointers
for funny things:

- Android implements pointer-tagging. The upper 16 bits of a pointer
are a tag, which can be used to validate it.  E.g. if you malloc
some space, free it and malloc again such that the same space
is returned, it will have a different tag. The hardware strips
away the tag; only the lower 48 bits (at most) is significant.

- A collection of techiques called NaN boxing can store a 50 bit
pointer, fully unboxed 64 bit double, or a 50 bit integer, in a 64 bit
word. This is a boon for dynamic languages, which can have unboxed
floats.

-- 
TXR Programming Language: http://nongnu.org/txr
Cygnal: Cygwin Native Application Library: http://kylheku.com/cygnal

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Thread

Why is glibc not extensive? Amit <amitchoudhary0523@gmail.com> - 2022-11-16 22:31 -0800
  Re: Why is glibc not extensive? Bart <bc@freeuk.com> - 2022-11-17 13:05 +0000
    Re: Why is glibc not extensive? A <amit234234234234@gmail.com> - 2022-11-17 05:18 -0800
      Re: Why is glibc not extensive? A <amit234234234234@gmail.com> - 2022-11-17 05:24 -0800
      Re: Why is glibc not extensive? Bart <bc@freeuk.com> - 2022-11-17 13:57 +0000
      Re: Why is glibc not extensive? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-11-17 17:04 +0000
      Re: Why is glibc not extensive? David Brown <david.brown@hesbynett.no> - 2022-11-18 09:32 +0100
        Re: Why is glibc not extensive? A <amit234234234234@gmail.com> - 2022-11-18 02:32 -0800
          Re: Why is glibc not extensive? David Brown <david.brown@hesbynett.no> - 2022-11-18 13:09 +0100
            Re: Why is glibc not extensive? A <amit234234234234@gmail.com> - 2022-11-18 04:47 -0800
              Re: Why is glibc not extensive? David Brown <david.brown@hesbynett.no> - 2022-11-18 13:59 +0100
                Re: Why is glibc not extensive? A <amit234234234234@gmail.com> - 2022-11-18 05:27 -0800
              Re: Why is glibc not extensive? Bart <bc@freeuk.com> - 2022-11-18 17:04 +0000
                Re: Why is glibc not extensive? David Brown <david.brown@hesbynett.no> - 2022-11-21 08:50 +0100
                Bart (Was: Why is glibc not extensive?) gazelle@shell.xmission.com (Kenny McCormack) - 2022-11-21 14:14 +0000
              Re: Why is glibc not extensive? Michael S <already5chosen@yahoo.com> - 2022-11-21 08:10 -0800
                Re: Why is glibc not extensive? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-11-26 09:07 -0800
                Re: Why is glibc not extensive? Michael S <already5chosen@yahoo.com> - 2022-11-26 16:11 -0800
                Re: Why is glibc not extensive? Kaz Kylheku <864-117-4973@kylheku.com> - 2022-11-27 13:05 +0000
                Re: Why is glibc not extensive? scott@slp53.sl.home (Scott Lurndal) - 2022-11-27 16:30 +0000
                Re: Why is glibc not extensive? BGB <cr88192@gmail.com> - 2022-11-27 12:20 -0600
                Re: Why is glibc not extensive? Bart <bc@freeuk.com> - 2022-11-27 21:13 +0000
                Re: Why is glibc not extensive? BGB <cr88192@gmail.com> - 2022-11-27 21:53 -0600
                Re: Why is glibc not extensive? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-12-03 01:17 -0800
        Re: Why is glibc not extensive? BGB <cr88192@gmail.com> - 2022-11-23 15:11 -0600
  Re: Why is glibc not extensive? Bonita Montero <Bonita.Montero@gmail.com> - 2022-11-17 19:05 +0100
    Re: Why is glibc not extensive? gazelle@shell.xmission.com (Kenny McCormack) - 2022-11-18 08:09 +0000
      Re: Why is glibc not extensive? BGB <cr88192@gmail.com> - 2022-11-23 13:55 -0600

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