Re: document AS_BASENAME

[Eric Blake]

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According to Stepan Kasal on 4/1/2006 10:13 AM:
> 
> 2) I'm not sure "basename /" is the only bug around.  The code shall be
> interpreted this way:
> 
>       "If it handles even basename /, we can hopefully trust it."
> 
> Thus I think it would be too adventurous to start using the buggy basename
> implementations right now, before the release.

True.

> 
> 3) Pre-computing the as_basename variable saves a subshell in each
> AS_BASENAME call with a non-trivial argument.  So _AS_BASENAME_PREPARE is
> an efficiency issue, too.  (I even considered adding _AS_DIRNAME_PREPARE.)

That's the clincher.  Actually, AS_DIRNAME is expanded more frequently
than AS_BASENAME in coreutils' configure, so I retract my previous
objection to leaving _AS_BASENAME_PREPARE, and would welcome the addition
of _AS_DIRNAME_PREPARE.

(I do some compatibility development on cygwin running on an old 266 MHz
Win98 machine, where every fork takes a full second of wall clock time, so
I know first hand how avoiding extra forks can speed up a shell script.)

- --
Life is short - so eat dessert first!

Eric Blake             address@hidden
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