[OMPI users] random MPI_UNIVERSE_SIZE

[Mathieu Gontier]

Hello,
I am trying to use MPI_Comm_spawn (MPI-2 standard only) and I have an 
problem when I use MPI_UNIVERSE_SIZE. Here my code:

int main( int argc, char *argv[] )
{
  int wsize=0, wrank=-1 ;
  int usize=0, urank=-1 ;
  int ier ;
  int usize_attr=0, flag=0 ;
  MPI_Comm MPI_COMM_UNIVERSE;
  ier = MPI_Init( &argc, &argv ) ;
  ier = MPI_Comm_size( MPI_COMM_WORLD, &wsize ) ;
  ier = MPI_Comm_rank( MPI_COMM_WORLD, &wrank ) ;
  ier = MPI_Comm_get_attr( MPI_COMM_WORLD, MPI_UNIVERSE_SIZE, (void*) 
&usize_attr, &flag ) ;
  if ( !flag ) { printf( "[manager][error] This MPI does not support 
MPI_UNIVERSE_SIZE.\n" ) ; return 1 ; }
  if( wrank==0 ) {
      ier = MPI_Comm_spawn( "./worker", argv, ( wsize/2 > 2 ? wsize/2 : 
2 ), MPI_INFO_NULL, 0, MPI_COMM_SELF, &MPI_COMM_UNIVERSE, 
MPI_ERRCODES_IGNORE);
      ier = MPI_Comm_size( MPI_COMM_UNIVERSE, &usize ) ;
      ier = MPI_Comm_rank( MPI_COMM_UNIVERSE, &urank ) ;
  }
  printf( "[manager] I am the process %d on %d in world (universe attr 
size: %d) and  %d on %d in universe\n", wrank, wsize, usize_attr, urank, 
usize ) ;
  MPI_Finalize();
  return 0;
}

When I call MPI_Comm_get_attr() with MPI_UNIVERSE_SIZE, my variable 
u_size_attr is random. Any idea?

Thank you.