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2005.01.28 19:58 "Re: issues with TIFFStreamOpen", by Frank Warmerdam
On Thu, 27 Jan 2005 14:45:14 -0500, Edward Lam <edward@sidefx.com> wrote:
> The TIFFStreamOpen() code was previously using tiff 3.4
> which didn't have this extra call to TIFFSeekOpen() from TIFFClientOpen().
>
> The comment in TIFFClientOpen() is still suspicious though:
>
> /*
> * This seek shouldn't be necessary, but I have had some
> * crazy problems with a failed fseek() on Solaris leaving
> * the current file pointer out of whack when an fwrite()
> * is done.
> */
> TIFFSeekFile( tif, 0, SEEK_SET );
>
> if (!WriteOK(tif, &tif->tif_header, sizeof (TIFFHeader))) {
> TIFFError(name, "Error writing TIFF header");
> goto bad;
> }
>
> Does anyone know why this was added? (Frank? Andrey?) The comment doesn't even
> make sense. Prior to the call to TIFFSeekFile() in TIFFClientOpen(), there's no
> calls to fwrite at all. We only call WriteOK() *after* calling TIFFSeekFile().
> So this means that if WriteOK() was messing up the file pointer, then doing the
> seek before wouldn't have an effect anyhow. Another problem with this code is
> that WriteOK() will not call fwrite() in general anyhow as WriteOK() ultimately
> just resolves to tif_writeproc which is passed down to TIFFClientOpen(). There's
> no requirement that tif_writeproc uses fwrite().
Edward,
I added the seek and the rather incoherent comment. As I recall it
really did work around some funky problem on Solaris. However,
I didn't reference a bug report nor provide a coherent explanation
about it so I would not mind if it was removed again.
Best regards,
--
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