[Omp] A problem with guard objects and exceptions on Intel

[Haab, Grant]

Michael,

I have reproduced the segmentation fault you mention below with your
source code.  I am in the process of submitting a bug for the Intel
Compiler on your behalf.  Thanks for bringing this issue to our
attention.

As you suggested in another e-mail, the bug seems to have nothing to do
with shell stack size.  It does not fail every time, so perhaps the
intermittent nature misled some folks to associate it with shell stack
size setting.

Best regards,

- Grant

Grant Haab
Compiler Developer
Intel Corporation

-----Original Message-----
From: omp-bounces at openmp.org [mailto:omp-bounces at openmp.org] On Behalf
Of Michael Suess
Sent: Tuesday, August 22, 2006 10:55 AM
To: omp at openmp.org
Subject: [Omp] A problem with guard objects and exceptions on Intel

Hi,

I have just published a blog entry comparing the merits of guard objects
vs. 
the critical construct (with C++ and OpenMP). The problem I have now is:
My 
test programs with exceptions and guard objects do not work for the
Intel 
Compiler. Since this would not be the first time I missed something, I 
figured I would double check here before filing a bug with Intel.

So if you find the time, please take a look at the code for the guard
object, 
enclosed in the following article:
http://www.thinkingparallel.com/2006/08/21/scoped-locking-vs-critical-in
-openmp-a-personal-shootout/

Combining this with the following short test program, 
test_omp_guard_exceptions.cpp:

#include <omp.h>
#include <cassert>

#include "omp_guard.hpp"

int main (void)
{
	omp_lock_t my_lock;

	// how many exceptions have been thrown (should be one for each
thread)
	int ex_count = 0;

	// how many threads will be created (most likely)
	int numthreads = omp_get_max_threads ();

	omp_init_lock (&my_lock);

	#pragma omp parallel
	{
		try {
			omp_guard my_guard (my_lock);
			throw omp_get_thread_num ();
		}
		catch(int e) {
			#pragma omp atomic
			++ex_count;
		}
	}
	assert (ex_count == numthreads);
	omp_destroy_lock (&my_lock);

	return 0;
}

Running this program on the Intel Compiler, I get a segmentation fault.
The 
Sun and Portland compilers run it just fine, so I think it may be a bug
in 
the compiler. But since I have had this thought one too many times in
the 
past and usually it is me and not the compiler who is wrong, I thought I

would double-check.

Thanks for any insights,
Michael Suess

-- 
My blog on parallel programming: http://www.thinkingparallel.com
Michael Suess
Public PGP key: http://www.suessnetz.de/michael/michaelsuess.gpg
PGP key fingerprint: A744 AFBA CA93 620B 8701 AB98 D4CF 4F3C 945A 61FE
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