Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Tue, 18 Nov 2014 16:48:31 -0600

Hi Michael,

On 11/17/2014 04:41 PM, Michael Davidsaver wrote:
> I've pushed a re-write of ringPointerTest which should address the
> occasional test failures we've been seeing.

Thanks, but running this on VxWorks I get:

ok 28 - !epicsRingPointerIsFull(ring)
ok 29 - epicsRingPointerGetFree(ring)==rsize
ok 30 - epicsRingPointerGetSize(ring)==rsize
ok 31 - epicsRingPointerGetUsed(ring)==0
# single producer, single consumer without locking
Bail out! Can't run test from thread with highest priority

If a test needs a specific thread priority, please start a thread that
meets those requirements and run it in that. The VxWorks shell by
default runs at the highest priority.

Also I am a little nervous about future compilers noticing that you're
creating pointers out of random integer offsets from a NULL pointer,
which assumes implementation-defined behaviour and on some of the more
obscure architectures could result in a trap representation (C99
6.3.2.3), e.g.
http://docs.cray.com/books/004-2179-001/html-004-2179-001/rvc5mrwh.html#ZFIXEDAWYU1A7W
Could this program not just malloc() a large buffer (1MB say) and make
up its pointers from offsets into that array?

- Andrew
-- 
People everywhere confuse what they read in newspapers with news.
-- A. J. Liebling

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System