[fitsbits] New routines for reading string keywords in CFITSIO

[William Pence]

On 3/24/2016 5:40 AM, Peter Weilbacher wrote:
> you say that the new set of routines will be /added/ to CFITSIO. But
> since function (2) of the new routines has the same name as function (1)
> of the existing routines

opps, the new routine will have a different name and will be called 
fits_read_str_key (as compared to the old routine name 
fits_read_key_str).  None of the old routines will be removed from 
CFITSIO so as to not break any existing software that use them.

These new routines will help insulate programmers from the peculiarities 
of how a particular string keyword is represented (or 'serialized' to 
use the current buzz word) in the FITS header.  For example, these 2 
keywords represent exactly the same information:

KEY1    = 'AABBCCDDEEFF' / My Comment
KEY2    = 'AABBCC&'
CONTINUE  'DDEEFF'  / My Comment

Similarly, consider the following 2 keywords

KEY3    = '1111111111222222222233333333334444444444&'
CONTINUE  '5555555555666666666612345678'
KEY4    = '1111111111222222222233333333334444444444&'
CONTINUE  '55555555556666666666123456789'

KEY3 and KEY4 are both character string keywords, and the only 
difference is that KEY4 is 1 character longer (69 characters) than KEY3 
(68 characters).  So in fact, KEY3 could have been serialized as a 
single keyword, but KEY4 would not fit on a single keyword.   The main 
point is that the CONTINUE convention is simply a different way of 
serializing the character string in a FITS keyword.

-Bill