[fitsbits] Re: where should END keyword be placed?

[Gil Rivlis]

A blank keyword with blank content is allowed by the FITS standard;
That mean that one can treat the 'empty' lines as empty keywords.
So, it is legal to put the END in the last card in the block; and your
program is not broken if it does not fill in the black words;

Gil
--
grivlis at as.arizona.edu

Michal Szymanski wrote:

> The latest release of IRAF package (2.11.3) introduced (I'm not quite
> sure if it has not appeared earlier but surely was not so in 2.10.x)
> a change in the way the header of a FITS file is written. The END
> keyword is placed not directly after the last record of the header but
> in the last 80-bytes record of current 2880-bytes chunk. In other words,
> the "empty" space in the last 2880 bytes is filled up not after END
> record but before it.
>
> This has broken some of my applications which add new keywords (in a
> sense that they start to add new 2880 bytes block although there is
> still space for new keywords). I had to change the code to check
> for "free" records before END record.
>
> At first I thought this is a (new?) requirement of FITS standard but
> when I downloaded latest (v. 2.0.36) "cfitsio" library and made a simple
> test I found that the library routines place END record in a
> "traditional" way, right after last header record and fill it up to next
> 2880 bytes *after* END.
>
> The question is: are both approaches standard-conformant?
>
> regards, Michal.
>
> --
>   Michal Szymanski (msz at astrouw.edu.pl)
>   Warsaw University Observatory, Warszawa, POLAND

--
Gil Rivlis
mailto:grivlis at as.arizona.edu