Henry,
Here is the MVF - minimum viable failure.  It looks like the culprit is
"read_image" which is just a cover for "readimg_jqtide_".  I'm running
under jconsole.

Set up in a directory with some .JPG files:
   FLS=: 0{"1 dir '*.jpg'
   createThreads 5
   MUTEX=: 10 T. 1    NB. Recursive mutex; either fails.

mtFileWork=: 3 : 0
   tm=. 6!:1''
   while. 0<#FLS do.
       tn=. ":3 T. ''                   NB. Thread number as char
       varnm=. ' '-.~'threadVar',tn
       smoutput 'Thread ',tn,' locking at ',":qts''
       11 T. y
       smoutput 'Thread ',tn,' locked at ',":qts''
       (varnm,' FLS')=: split FLS
       smoutput 'Thread ',tn,' unlocking at ',(":qts''),' for file ',flnm=.
>".varnm
       13 T. y
       smoutput 'Thread ',tn,' unlocked at ',":qts''
       #read_image flnm   NB. ¡Fails here!
    end.
    tm=. tm,~6!:1''
NB.EG mtFileWork t. '' MUTEX [ mtFileWork t. '' MUTEX [ mtFileWork t. ''
MUTEX [ mtFileWork t. '' MUTEX [ mtFileWork t. '' MUTEX
)

Any help is appreciated!

Thanks,

Devon

On Tue, May 10, 2022 at 4:46 PM Henry Rich <henryhr...@gmail.com> wrote:

> If you can get me a version that fails on Windows I'll look at it.
>
> Henry Rich
>
> On 5/10/2022 4:20 PM, Devon McCormick wrote:
> > Hi,
> >
> > Has anyone had success using the multi-threading mutex primitives?  I've
> > had limited success - I'll be presenting some basic routines at NYCJUG
> this
> > evening (18:00 EDT -
> > https://www.meetup.com/J-Dynamic-Functional-Programming/) - but have
> been
> > unable to run multiple threads on a real-life process without crashing J.
> >
> > The following simplified demo seems to work OK but the version of this
> > where I do actual work crashes - with "Process shell<1> exited abnormally
> > with code 5" -  after two to thirty repetitions.
> >
> >     MUTEX=: 10 T. 0    NB. Fast mutex
> >     createThreads=: 3 : '{{ 0 T. '''' }} ^:y]'''''
> >     qts=: 6!:0
> >     createThreads 5
> >     GVAR=: 100?@$1e6                    NB. Initialize global threads
> will
> > consume
> >
> > multiLockMsgUnlock=: 3 : 0
> >     while. 0<#GVAR do.
> >         tn=. ":3 T. ''                   NB. Thread number as char
> >         varnm=: ' '-.~'threadVar',tn
> >         smoutput 'Thread ',tn,' locking at ',":qts''
> >         11 T. y
> >         smoutput 'Thread ',tn,' locked at ',":qts''
> >         (varnm,' GVAR')=: split GVAR
> >         smoutput 'Thread ',tn,' unlocking at ',(":qts''),' with
> > ',tn,'=',":".varnm
> >         13 T. y
> >         smoutput 'Thread ',tn,' unlocked at ',(":qts''),';
> #GVAR=',":#GVAR
> >      end.
> > )
> > NB. Start five processes (one line):
> > multiLockMsgUnlock t. '' MUTEX [ multiLockMsgUnlock t. '' MUTEX [
> > multiLockMsgUnlock t. '' MUTEX [ multiLockMsgUnlock t. '' MUTEX [
> > multiLockMsgUnlock t. '' MUTEX
> >
> > The actual work I'm doing is on files, a list of whose names corresponds
> to
> > the GVAR vector above.
> >
> > Any suggestions are welcome.
> >
> > Cheers,
> >
> > Devon
> >
>
>
> --
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>


-- 

Devon McCormick, CFA

Quantitative Consultant
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