truncating a file opened via open()

[Larry Campbell]

> > >In article <340 at cmu-cs-edu1.ARPA> hua at cmu-cs-edu1.ARPA (Ernest Hua) writes:
> > >>Does anyone have any idea how to truncate a file at the current point in
> > >>writing if it is opened by open()?
> 
> There are precisely two solutions for non-4.2BSD systems:
> 1) implement (f)truncate on your system...

Kind of tough for people without source licenses (I know, I'm whining).

> 2) Copy the entire file, up to the point of truncation, to a temporary file,
> then copy it back to the original file.
>
> 	Guy Harris

I don't see how this works unless you unlink the file and then re-creat
it before writing it back.  But the original question implied you only had
a descriptor for the file, not a name...  so you can't unlink or re-creat
it.  And even if you knew the name, other links wouldn't get truncated.
Sounds like it's pretty tough to fake this one ...  sigh ...

- Larry Campbell
  The Boston Software Works, Inc., 120 Fulton St., Boston MA 02109
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