[Info-vax] Suppressing DCL exit status messages

[Ian Miller]

On Tuesday, September 12, 2023 at 1:34:40 PM UTC+1, Simon Clubley wrote:
> On 2023-09-11, gah4 <ga... at u.washington.edu> wrote: 
> > 
> > It was a C program that I wrote, and that had exit(8); in it. 
> > 
> > There was no access violation. 
> > 
> 
> I am surprised nobody told you the error message could be suppressed 
> if you set the right bit in the exit status you return to DCL: 
> 
> $ exit 8 
> %SYSTEM-W-ACCVIO, access violation, reason mask=00, virtual address=0000000000000008, PC=000000007AF0D9F0, PS=00000000 
> $ write sys$output $status 
> %X00000008 
> 
> $ exit %x10000008 
> $ write sys$output $status 
> %X10000008 
> 
> Note that it's that specific bit which needs setting as you still get 
> the message in this case: 
> 
> $ exit %x40000008 
> %SYSTEM-W-ACCVIO, access violation, reason mask=00, virtual address=0000000040000008, PC=000000007AF0D9F0, PS=00000000 
> $ write sys$output $status 
> %X40000008 
> 
> You can mask off the top 4 bits (the internal control flags) to 
> extract out the actual number your program returned to your DCL script. 
> 
> Not sure where I found this out because it's not in the manuals 
> I just checked. 
> 
> Simon. 
> 
> -- 
> Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP 
> Walking destinations on a map are further away than they appear.

See the OpenVMS Calling Standard chapter on OpenVMS Conditions where all this is documented https://docs.vmssoftware.com/vsi-openvms-calling-standard/#VMSCONDITIONS_CHAP