[Info-vax] SYS$FAO coding example in BLISS-32

[Hunter Goatley]

On 7/12/2024 1:17 AM, David Meyer wrote:
> Jim Duff <jim at bad.invalid> writes:
> 
>         MSGDESC[0] = .RSLT;              ! Modify output descriptor
>      ..............^
>      %BLS32-W-TEXT, Fetch or store applied to field of zero size
>      at line number 29 in file DISK$USER_01:[PAPA]SHOWTIMEUM.B32;2
> 
> However, changing the flagged line as follows allows the example to
> compile and run as expected:
> 
>      MSGDESC [DSC$W_LENGTH] = .RSLT;
> 

In BLISS, structures are referenced by field selectors.

If you look at the definition of DSC$W_LENGTH in 
SYS$LIBRARY:STARLET.REQ, you'll see that it is:

macro DSC$W_LENGTH = 0,0,16,0 %;        !  A one-word field specifiec to 
the descriptor class;

The four field selectors are OFFSET, POSITION, WIDTH, SIGN.

Hunter