Re: Customized Allocator (on disk)

[Phil Edwards <pedwards at disaster dot jaj dot com>]

On Mon, Dec 03, 2001 at 02:14:58AM -0800, Reza Roboubi wrote:
> This is essentially the ability to create a hash ON THE DISK.   An ability that
> appears _lacking_ from the STL standard.  Its addition would  make the GNU
> implementation great for certain database applications.  And it should be easy to
> add.

It's lacking from the standard because the standard doesn't say anything
about disks, hashes, or how to access them.  It doesn't even assume that
"files" exist.

Right now libstdc++ only goes down to the stdio level.  I suspect this would
probably be too slow for what you had in mind.

What exactly do you mean by "on the disk"?  Just stored as a normal file,
or accessing the disk sectors directly, or via mmap(), or...?  Most of
the major databases do something like the second option, bypassing the
filesystem entirely to gain speed.  The library can't do much more than
the first option without getting ourselves into trouble.


> My question is related to developing code for the GNU _implementation_ of STL.   I
> am under the impression that it is _fully_ relevant to this list.  If not,  then
> please change the information on  your  web site which misled me.

Yes, this is the right place.  I couldn't tell what you had in mind from
your original message.  It's clear now.


Phil

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