Re: Add SHELL_EXIT_CODE to psql

Justin Pryzby <pryzby@telsasoft.com> writes:
> The exit status is one byte.  I think you should define the status
> variable along the lines of:

>  - 0 if successful; or,
>  - a positive number 1..255 indicating its exit status. or,
>  - a negative number N indicating it was terminated by signal -N; or,
>  - 256 if an internal error occurred (like pclose/ferror);

> See bash(1).  This would be a good behavior to start with, since it
> ought to be familiar to everyone, and if it's good enough to write/run
> shell scripts in, then it's got to be good enough for psql to run a
> single command in.

I'm okay with adopting bash's rule, but then it should actually match
bash --- signal N is reported as 128+N, not -N.

Not sure what to do about pclose/ferror cases.  Maybe use -1?

> I'm not sure why the shell uses 126-127 specially, though..

127 is used similarly by system(3).  I think both 126 and 127 might
be specified by POSIX, but not sure.  In any case, those are outside
our jurisdiction.

            regards, tom lane