Re: no exit status available when a command doesn't exist or fails in pipe to grep

[Ed Morton]

On 9/6/2021 12:47 PM, Neil R. Ormos wrote:
> ED MORTON wrote:
>
> > I was just trying to write a function that would
> > do the same for awk that command substitution
> > does for shell, i.e. run some command and use
> > it's output in some context, e.g.:
> > [...]
> > but I need to know the exit status if the
> > pipeline failed to be able to do that robustly.
> > I thought I'd have that exit status in the
> > result of the pipeline:
> > [...]
> > or in ERRNO:
> > [...]
> > but clearly I don't. Should `ERRNO` be populated
> > in that situation? If not, is there any other
> > way for me to get the exit status of the command
> > that I ran to pipe it's output to getline, like
> > I'd have it in the return from system() (which
> > obviously I can't use for this task):
> Use the value returned by close().
>
> The "Closing Input and Output Redirections"
> section of the manual says:
>
> | In gawk, starting with version 4.2, when closing
> | a pipe or coprocess (input or output), the
> | return value is the exit status of the command,
> | as described in Table 5.1.29

Perfect:

   $ awk 'BEGIN{cmd="garbage"; (cmd | getline); print close(cmd)}'
   sh: garbage: command not found
   127

I know this is a gawk mailing list but I don't suppose you know of a 
POSIX equivalent?

   $ awk --posix 'BEGIN{cmd="garbage"; (cmd | getline); print close(cmd)}'
   sh: garbage: command not found
   0

Thanks!

    Ed.