Re: exit

[Aharon Robbins]

Greetings. Re this:

> Date: Wed, 4 Feb 2004 13:33:45 +0100
> From: address@hidden
> To: Aharon Robbins <address@hidden>
> Cc: address@hidden
> Subject: Re: exit
>
> Look at this:
>
> address@hidden:~$ awk 'BEGIN { "date" | getline date; print date; 
> system("sleep 2"); "date" | getline date; print date }'
> Wed Feb  4 13:27:36 CET 2004
> Wed Feb  4 13:27:36 CET 2004
> address@hidden:~$ awk 'BEGIN { "date" | getline date; print date; 
> system("sleep 2"); "date -u" | getline date; print date }'
> Wed Feb  4 13:27:48 CET 2004
> Wed Feb  4 12:27:50 UTC 2004
>
> This is probaby the same problem with descriptors. If i use two times the
> same command through pipe i receive the same result. :(
>
> Jozef
>
> PS: i'm GMT+1

This is not a bug. It's documented behavior.  The pipe stays open until
closed with close().  In this case, since the "date" command only produces
one line of output, the second getline does not change the `date' variable.
Since "date -u" is a different command, you do get different results:

        $ cat > dateme.awk
        BEGIN {
                "date" | getline date
                print date
                close("date")
                system("sleep 2")
                "date" | getline date
                print date
                close("date")
        }
        $ awk -f dateme.awk 
        Wed Feb  4 15:20:59 IST 2004
        Wed Feb  4 15:21:01 IST 2004

See the gawk manual.

Arnold