On Sun, 07 Feb 2010 22:40:55 -0500, Prentice Bisbal <prent...@ias.edu> wrote: > Hello, everyone. I'm having trouble packing/unpacking this structure: > > typedef struct{ > int index; > int* coords; > }point; > > The size of the coords array is not known a priori, so it needs to be a > dynamic array. I'm trying to send it from one node to another using > MPI_Pack/MPI_Unpack as shown below. When I unpack it, I get this error > when unpacking the coords array: > > [fatboy:07360] *** Process received signal *** > [fatboy:07360] Signal: Segmentation fault (11) > [fatboy:07360] Signal code: Address not mapped (1) > [fatboy:07360] Failing at address: (nil)
Looks like b_point.coords = NULL. Has this been allocated on rank=1? You might need to use MPI_Get_count to decide how much to allocate. Also, if you don't have a convenient upper bound on the size of the receive buffer, you can use MPI_Probe followed by MPI_Get_count to determine this before calling MPI_Recv. Jed