Re: pThreadCreate() in RPGLE

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

Hi Srikanth,

> Is it possible to create multithreaded programs in RPGLE, some time back
> I had coded multithreaded programs in C/400 using POSIX APIs (pthread
> APIs).

No, sorry.  Unfortunately, RPG programs cannot be multi-threaded.  The RPG
compiler uses static storage for many of it's internal control structures
in a manner that is not threadsafe.

You can call an RPG program from a multi-threaded application by coding
THREAD(*SERIALIZE) on the H-spec, but it's important to understand what
that does -- it prevents multiple threads from running the RPG code
concurrently...  which usually defeats the purpose of making your
application multi-threaded in the first place ;)


> I now have do the same but in RPGLE, can I get some helpful links or
> reference to sample programs. I checked out QUSRTOOL on my box but in
> vain.

An alternative might be to use more than one job instead of more than one
thread -- in this environment, there's no issue with threadsafety.  You
can use sockets or data queues, etc to synchronize and pass data between
the jobs.

There may be other alternatives as well, depending on what you want to
accomplish with the threads.

Of course, you can always use Java or C to write a multi-threaded
application on the iSeries.  Starting in V5R1, C and RPG are part of the
same package, so if you've got a license to use the RPG compiler, the same
license lets you use the C compiler.   And Java is free, I believe, in
OS/400 -- comes with the operating system.

Good Luck