I think we are almost saying the same thing. But to be sure, I will restate. The call to opal_pointer_array_add() can return either an index (which I assume is a positive integer, maybe also 0?) or OPAL_ERR_OUT_OF_RESOURCE (which is a -2) if it cannot malloc anymore space in the table.  So, I guess I agree that the original code was wrong as it never would have detected the error since OMPI_ERROR != OPAL_ERR_OUT_OF_RESOURCE.  (-1 != -2)

Since we are overloading the return value, it seems like the only thing we could do is something like this:

if (new_group->grp_f_to_c_index < 0)

But that does not follow the SOS logic as the key is that we want to compare to OMPI_SUCCESS (I think).  Also, for what it is worth, the setting of the grp_f_to_c_index happens in the group constructor, so we cannot get at the return value of opal_pointer_array_add() except by looking at the grp_f_to_c value after the object is constructed.  I am not sure the correct way to handle this.


On 05/18/10 14:02, Jeff Squyres wrote:
Looks like the comparison to OMPI_ERROR worked by accident -- just because it happened to have a value of -1.  

The *_f_to_c_index values are the return value from a call to opal_point_array_add().  This value will either be non-negative or -1.  -1 indicates a failure.  It's not an *_ERR_* code -- it's a -1 index value.  So the comparisons should really have been to -1 in the first place.

Rolf / Abhishek -- can you fix?  Did this happen in other *_f_to_c_index member variable comparisons elsewhere?

On May 18, 2010, at 1:25 PM, Rolf vandeVaart wrote:

I am getting SEGVs while running the IMB-MPI1 tests.  I believe the
problem has to do with changes made to the group_init.c file last
night.  The error occurs in the call to MPI_Comm_split.

 There were 4 changes in the file that look like this:
if (OMPI_ERROR == new_group->grp_f_to_c_index)

if (OMPI_SUCCESS != new_group->grp_f_to_c_index)

If I change it back, things work.  I understand the idea of changing the
logic, but maybe that does not apply in this case?    When running with
np=2, the value of new_group->grp_f_to_c_index is 4, thereby not
equaling OMPI_SUCCESS and we end up in an error condition which results
in a null pointer later on.

Am I the only that has run into this?


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