Re: [ECOS] Newbie-Q: Clean exits from tests and examples

[John Mills <johnmills@speakeasy.net>]

Sergei and Andrew -

Thanks for your inputs and excellent explanation. I'm getting somewhat
clearer ideas as I play with the examples.

The context is that I have a moderately complex embedded eCos/MIPS
(mipsisa32-elf-) application and would like to simulate parts of it
multiply and concurrently in a Linux host environment. There is actually
no reason for my simulators to close and exit (other than malfunction)
until I kill them from Linux. In that sense it was a rhetorical question,
but it reflected something basic with eCos that I hadn't thought about.

I wrote a simple script to invoke one instance of the 'twothreads' example 
and log its output to a distinct file, which I could then watch from a 
dedicated xterm using 'tail -f ...':

+++++++++++++++++++++++++++<start_thread.sh>+++++++++++++++++++++++++
#!/bin/sh
proc_no=$$
echo Starting process $proc_no
(./twothreads > threads.$proc_no) &
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

On Wed, 16 May 2007, Sergei Gavrikov wrote:

> On Wed, May 16, 2007 at 09:58:53AM -0500, John Mills wrote:
> > Hello -
> > 
> > I'm getting started with the eCos-2.0 'synthetic' target and have a couple 
> > of beginner's questions.

> > Question: How should 'examples/hello.c' be structured to run and exit, 
> > returning cleanly to the parent Linux shell, or how should I invoke it?
 
> Answer: main(){printf("hello, world!\n");cyg_hal_sys_exit(0);}
 
> That's normal. The _tests_ for the synthetic target usually is finished
> by the CYGHWR_TEST_PROGRAM_EXIT (include/cyg/hal/hal_intr.h). So, there
> is the cyg_hal_sys_exit(0) in those wallclock* tests.
 
> And you can see that examples/hello.c exits from main with return 0.
> That's UNIX way. But eCos != UNIX. Where has to return the application?
> You can easy see the difference using GDB, set a breakpoint either to
> the 'cyg_test_exit' call (for the tests) or to the 'exit' call (for the
> POSIX sources). And more, try to run the synthetic executables from
> shell as 'appname --io'.
 
>   Sergei

 - John Mills
   john.m.mills@alum.mit.edu


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