Re: [jed-users] new_process() can't handle input file > 65536 bytes?

["John E. Davis" <jed@xxxxxxxxxxx>]

Tom Culliton <tom.culliton@xxxxxxxxx> wrote:
> Yeah, but likely a system pipe buffer size.

Yes, that’s my understanding. The process will exit only after it has
successfully written all data to the pipe. In this scenario, it got
stuck because the pipe was full.

Thanks,
--John

>
> On Sun, Jun 29, 2025, 16:10 Roland Hughes <roland@xxxxxxxxxxxxxxxxxxxx>
> wrote:
>
>> Color me confused.
>>
>> If he deletes one line from the scratch buffer of 65537 lines it works.
>>
>> If the buffer is 65537 (or presumably greater) it doesn't.
>>
>> How does it work with just one line less if cat is always waiting for
>> input?
>>
>> It's okay to say I'm an imbecile here. I'm desperately trying to get all
>> of the page breaks and numbers into a new novel that will hopefully be
>> available for sale prior to the fourth, so might have missed something.
>> It sure sounded like he ran headlong into a hard coded 64K buffer size
>> somewhere.
>>
>> On 6/29/2025 2:44 PM, John E. Davis wrote:
>> > Morten Bo Johansen <mbj@xxxxxxxxx> wrote:
>> >> If you have the time, then create a file, "t", of 65537 bytes
>> >>
>> >>     $ for i in {1..65537}; do echo -n a >> t; done
>> >>
>> >> In a *scratch* buffer, insert the following lines:
>> >>
>> >>     require("process");
>> >>     variable obj = new_process(["cat"]; write=1, stdin="t");
>> >>     () = obj.wait();
>> > The issue here is that the "cat" process is waiting for you to read
>> > the data.  For example, add
>> >
>> >     () = fgets (&str, obj.fp1);
>> >
>> > before calling the wait method.  If you want the output of cat to go
>> > to stdout, then omit the write=1 qualifier.  From the documentation:
>> >
>> >     write=fds
>> >
>> >      fds is a list of integer file descriptors that are open for write
>> >      access in the subprocess, and may be read to by the calling
>> >      process using the fdN or fpN fields of the structure.
>> > [...]
>> >    Mimic popen(pgm, "r"):
>> >
>> >     obj = new_process (pgm; write=1);   % Read from obj.fp1
>> >
>> > I hope this helps,
>> > --John
>> >
>> >
>> >> and then:
>> >>
>> >>     alt-x evalbuffer
>> >>
>> >> In my case the process hangs/freezes.
>> >>
>> >> If I remove one single 'a' from the file "t" to make the size 65536
>> bytes,
>> >> then it completes.
>> >>
>> >> Is it a case of some integer data type somewhere in the slang source
>> files
>> >> that should be changed or is it just me who don't know what I'm doing?
>> >>
>> >> Regards,
>> >> Morten
>> >> _______________________________________________
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>> >>
>> > _______________________________________________
>> > For list information, visit <http://jedsoft.org/jed/mailinglists.html>.
>> >
>> --
>> Roland Hughes, President
>> Logikal Solutions
>> (630)-205-1593  (cell)
>> https://theminimumyouneedtoknow.com
>> https://infiniteexposure.net
>> https://johnsmith-book.com
>>
>> _______________________________________________
>> For list information, visit <http://jedsoft.org/jed/mailinglists.html>.
>>
>>
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