[mpich-discuss] Help : Sending a pointer type data to other nodes

[Steven Liu]

Hi,

    I want to send a data as pointer type in C to the other nodes. 
Is there any method to do so? I tried several times. But failed. 
Thanks a lot. 

PS: Purpose -- make a variable which can be read and written by the other nodes.

My code is attached below:

#include <stdlib.h>
#include <string.h>
#include "mpi.h"

int main(int argc,char *argv[])
{
 int myid, numprocs;
 
 double *ptr;
 double Q[1];
 Q[0]=1.3;
 Q[1]=7.3;
 
 MPI_Init(&argc,&argv);
    MPI_Comm_size(MPI_COMM_WORLD,&numprocs);
    MPI_Comm_rank(MPI_COMM_WORLD,&myid);
 
 if (myid == 0) {
 
  ptr = &Q;
  MPI_Bcast((void*)&ptr, 1, MPI_DOUBLE, 0, MPI_COMM_WORLD);
  printf("\n");
  printf("sizeof pointer %d\n", sizeof(ptr));
  printf("ptr has the value %p and is stored at %p\n", ptr, (void*)&ptr);
  printf("The value of the integer pointed to by ptr is %f\n", *ptr);
  printf("Second address of ptr has the value %p and is valued at %f\n", ptr+1, *(ptr+1));
  
 }
 else{
 
  MPI_Bcast(ptr, 1, MPI_DOUBLE, 0, MPI_COMM_WORLD);
  printf("\n");
  printf("ptr has the value %p and is stored at %p\n", ptr, (void*)&ptr);
  printf("The value of the integer pointed to by ptr is %f\n", *ptr);
  printf("Second address of ptr has the value %p and is valued at %f\n", ptr+1, *(ptr+1));
 }

 MPI_Finalize();
    return 0;
}

With all my best wishes.


Yours, Dongping Liu

Group M02
State Key Laboratory of Magnetism
Institute of Physics
Chinese Academy of Sciences
P.O.Box 603, Beijing 100190, P. R. China
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/mpich-discuss/attachments/20090324/f6c79ce1/attachment.htm>