Re: Linux Calls

[Simon Wright <simon@pushface.org>]

"Jeremy Smith" <jeremy.t.smith@mindspring.com> writes:

> I have two tasks, built using gnat 3.13p, running under Linux, Red Hat 8.
> The idea was to have one task processing and performing cyclic tasks
> continuously while the other task waits for commands and responds to them
> right away.  To accomplish this I am want to run the command receipt task at
> a higher priority than the continuous processing task.  My problem is that
> the commands are coming over an IPC message queue, so when the command
> receipt task calls msgget (visible via pragma Import) it blocks but does it
> outside the Ada RTS.  The continuous processing task never gains context
> because the Ada RTS doesn't know the command receipt task has blocked
> pending receipt of the next command.
> 
> Anybody know a way to wrap a blocking OS call so that the other lower
> priority Ada tasks can play until it returns?

It sounds as though you're using the "fsu" version of the runtime
system - you need the version that uses native threads. On recent
editions of GNAT, & I'm pretty sure on 3.13p, you get a choice between
fsu & native; check out the installation instructions. (as far as I
can remember, it involves switching the symlinks for adainclude,
adalib in ...lib/gcc-lib/i686-pc-linux-gnu/2.8.1/ .

The binary I have is called gnat-3.13p-i686-pc-linux-gnu-bin.tar.gz