Re: Reading /dev/stdin Input with a Timeout

[Ed Morton]

Though this doesn't work:

   GAWK_READ_TIMEOUT=1000 gawk '
        { print "You entered: " $0 }
   '

this does:

   GAWK_READ_TIMEOUT=1000 gawk '
        BEGIN {
            if ( !("-","READ_TIMEOUT") in PROCINFO ) {
                PROCINFO["-","READ_TIMEOUT"] = ENVIRON["GAWK_READ_TIMEOUT"]
            }
        }
        { print "You entered: " $0 }
   '
   gawk: cmd. line:4: fatal: error reading input file `-': Connection
   timed out

so there's a workaround, though it seems like a fix should be possible 
for this GAWK_READ_TIMEOUT problem (which is apparently different from 
John's original PROCINFO["-","READ_TIMEOUT"]  MinGW problem).

    Ed.

On 12/14/2023 4:05 AM, Ed Morton wrote:
> I'm also using a 64-bit gawk (the one installed by the 64-bit cygwin 
> setup.exe).
>
> While this works for me (as does your original script):
>
>     $ gawk 'BEGIN{PROCINFO["-","READ_TIMEOUT"]=1000} {print "You
>     entered: " $0}'
>     gawk: cmd. line:1: fatal: error reading input file `-': Connection
>     timed out
>
> none of these do, I have to interrupt each of them:
>
>     $ GAWK_READ_TIMEOUT=1000 gawk 'BEGIN{print "GAWK_READ_TIMEOUT="
>     ENVIRON["GAWK_READ_TIMEOUT"]} {print "You entered: " $0}'
>     GAWK_READ_TIMEOUT=1000
>
>     $ export GAWK_READ_TIMEOUT=1000; gawk 'BEGIN{print
>     "GAWK_READ_TIMEOUT=" ENVIRON["GAWK_READ_TIMEOUT"]} {print "You
>     entered: " $0}'
>     GAWK_READ_TIMEOUT=1000
>
>     $ gawk 'BEGIN{ENVIRON["GAWK_READ_TIMEOUT"]=1000; print
>     "GAWK_READ_TIMEOUT=" ENVIRON["GAWK_READ_TIMEOUT"]} {print "You
>     entered: " $0}'
>     GAWK_READ_TIMEOUT=1000
>
> FWIW some environment variables DO work:
>
>     $ POSIXLY_CORRECT=1 gawk 'BEGIN{print gensub(/x/,"y",1,FS)}'
>     gawk: cmd. line:1: warning: regexp constant for parameter #1
>     yields boolean value
>     gawk: cmd. line:1: fatal: function `gensub' not defined
>
>     $ GAWK_MSG_SRC=1 POSIXLY_CORRECT=1 gawk 'BEGIN{print
>     gensub(/x/,"y",1,FS)}'
>     gawk: cmd. line:1: warning: regexp constant for parameter #1
>     yields boolean value
>     gawk:
>     
> /cygdrive/d/a/scallywag/gawk/gawk-5.3.0-1.x86_64/src/gawk-5.3.0/interpret.h:1297:cmd.
>     line:1: fatal: function `gensub' not defined
>
> Regarding your Aside, you're welcome and "Thanks for noticing me" 
> (Eeyore).
>
>     Ed.
>
> On 12/13/2023 11:38 PM, J Naman wrote:
> > I tried with and without BEGIN{ ENVIRON["GAWK_READ_TIMEOUT"]=1000.  
> > Did you set it before invoking gawk? Also, I am using 64-bit gawk 
> > compiled by Volker Kiefel volker.kiefel@freenet.de 
> > http://vkiefel.de/compiled-sw/gawk-5.3.0-win64.zip
> > The benchmark tests you & I did the other day ran 6% faster under 
> > gawk 64-bit vs gawk 32-bit (eli-zaretskii, Ezwinports). I guess I was 
> > expecting a little faster, but not complaining. What I really want is 
> > access to more ram, which I get.
> > I'll try a few other things to see how timeout works. Just to be able 
> > to match results with you and others. I can easily live without the 
> > timeout.
> >
> > Aside: I see and read many things you have written about gawk up to 
> > 20 years ago. The compilation of Ed Morton's responses on Stack 
> > Overflow/stackexchange would be a great gawk guide. Thanks for years 
> > of selfless sharing! John naman
> >
> >
> >
> > On Wed, Dec 13, 2023 at 8:27 PM Ed Morton <mortoneccc@comcast.net> wrote:
> >
> >     FWIW it works for me with gawk 5.3 on cygwin.
> >
> >     Just out of curiosity, do you have the same problem if you set
> >     the `GAWK_READ_TIMEOUT` environment variable instead of
> >     `PROCINFO["/dev/stdin", "READ_TIMEOUT"]`?
> >
> >         Ed.
> >
> >     On 12/13/2023 7:07 PM, J Naman wrote:
> > >     Date: Thu Dec 14 2023 00:34:43 UTC
> > >     Configuration Information [Automatically generated, do not change]:
> > >
> > >     Gawk Version: GNU Awk 5.3.0, API 4.0
> > >     Machine: AMD64(64-bit gawk)
> > >     OS: Windows_NT = Win 7 [Version 6.1.7601]
> > >     platform: mingw
> > >     LC_ALL: C
> > >     I have read:https://www.gnu.org/software/gawk/manual/html_node/Bugs.html
> > >        Yes or No: Yes
> > >
> > >     Description:
> > >     PROCINFO["/dev/stdin", "READ_TIMEOUT"] = 1000
> > >     getline < "/dev/stdin"
> > >     # does not timeout in 1 second; waits (forever) until Return key is pressed
> > >     # ERRNO is not set if timeout is exceeded
> > >     # Ref: 4.11 Reading Input with a Timeout, p.96
> > >
> > >     Comment: This behavior MIGHT be due to the Mingw-console and not be a bug.
> > >     print "Hello World" >"/dev/con" works on gawk mingw platform.
> > >
> > >     Obviously this is not a debilitating bug, but I thought that I should
> > >     report it.