Re: How to get gawk to timeout when reading a file.

[Andrew J. Schorr]

Hi,

> #!/usr/bin/gawk -f 
> 
> BEGIN{
>     # Polling read...
>     PROCINFO[Service, "READ_TIMEOUT"] = 1000;

What's the value of the Service variable here?
It should be set to "../fifo", I hope.

>     PROCINFO["input", "RETRY"] = 1; 

Shouldn't this be:
     PROCINFO["../fifo", "RETRY"] = 1; 
?

> 
>     system("sleep 1s; echo Run process using system.");
> 
>     do
>     {
>         ret = getline < "../fifo";
>         # Quickly eat the rest of the input which could
>         # not be read due to the other process running.
>     }
>     while(ret == 1);
> }
> 
> As you can see, I'm reading from a FIFO. The process on the other end
> sends data once per second. It is:
> sudo /usr/sbin/iftop -tB | stdbuf -oL grep 'Total receive rate:' > fifo
> 
> If you can get the code sample to work correctly, then the program will
> exit while the process feeding the fifo is still running.

Have you tried running strace on the gawk script to see in which call
it's blocking?

Regards,
Andy