🚀 go-pugleaf

In article <91773@bu.edu>, tesco@bumetb.bu.edu (Dances With Babes) writes:
|> Does anyone know if the "set -o noclobber" command is atomic?
|> I'm trying to implement a semaphore in ksh, and this would be a good way,
|> provided it's atomic (that it,  no two people can create the file at the same time).
|> 
|> If it's not atomic, anyone know of a good way
|> to implement a semaphore using ksh?
|> 
|> 
|> -tesco

Sorry I don't have the answer to your specific question.

But before people go off and try doing things with "set -o noclobber",
I wanted to let people know there is a bug with "set -o noclobber"
in the latest release of ksh from the Toolchest (ksh88g), at least
on some systems, specifically mine (Sun OS 4.1.1).

In a phrase, it doesn't work.  It's as if you have noclobber
disabled, even though set -o shows it's enabled, so overwriting a
file with > redirection silently overwrites that file.

I passed my findings on to David Korn and here was his response:

: Date: Wed, 8 Apr 92 23:39:33 EDT
: 
: This is a serious problem.  The code uses POSIX style
: macros to test file attributes.  However, since the type
: field for regular files can be zero, my code can't
: distinguish between files that don't exist and regular
: files.
: 
: I will have to put together an 'h' point release for
: release very soon.
: 
: Thanks for reporting the problem.  It looks as if
: most people do not use noclobber or else the problem
: would have been reported sooner.
: 

If you're not running ksh88g you should be OK as the problem
is NOT present in previous releases of ksh from the Toolchest.
The Toolchest says the latest release is still 88g and said
ksh-92 is coming.  No mention of ksh88h yet.  If anyone knows
what's going on with 88h, let me know or post it.  Thanks.

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