Hi,
I'm currently implementing a mechanism to piggyback information on
messages. On message sending, I dynamically create a new datatype
composed of the original buffer and of the data to piggyback.
For instance, if I want to piggyback an integer on each message, I use
the following code:
int send(void *buf,
size_t count,
struct ompi_datatype_t* datatype,
int dst,
int tag,
mca_pml_base_send_mode_t sendmode,
ompi_communicator_t* comm )
{
MPI_Datatype type[2];
int blocklen[2];
MPI_Aint disp[2];
MPI_Datatype datatype_out;
int piggy=0;
type[0]=datatype;
type[1]=MPI_INT;
blocklen[0]=count;
blocklen[1]=1;
MPI_Address(buf,disp);
MPI_Address(&piggy,disp+1);
MPI_Type_struct(2, blocklen, disp, type, datatype_out);
MPI_Type_commit(datatype_out);
/* then I call the original send function and send my new datatype */
original_send(MPI_BOTTOM, 1, datatype_out, dst, tag, sendmode,
comm);
}
This code works well. But if the data I want to piggyback is dynamically
allocated. I get this kind of error message:
../../ompi/datatype/datatype_pack.h:40
Pointer 0x823fab0 size 4 is outside [0xbfef8920,0x823fab4] for
base ptr (nil) count 1 and data
Datatype 0x8240b90[] size 8 align 4 id 0 length 3 used 2
true_lb -1074820832 true_ub 136575668 (true_extent 1211396500) lb
-1074820832 ub 136575668 (extent 1211396500)
nbElems 2 loops 0 flags 102 (commited )-c-----GD--[---][---
Despite this message, the function works well too ...
Can someone explain me what this message means ? It seems that in the
first part of the error message, the lower bound and the upper bound of
the datatype are switched, but I don't know why.
Regards.
Thomas Ropars
