program gather
      include "mpif.h"
      
      integer rank, size, ierr, MAXPROCS
      parameter(MAXPROCS=20)
      character*30 message
      character*30 allmessages(MAXPROCS)
      integer root
      parameter(root = 0)

      call MPI_Init(ierr )      ! You should
      call MPI_Comm_size( MPI_COMM_WORLD, size, ierr ) ! always check
      call MPI_Comm_rank( MPI_COMM_WORLD, rank, ierr ) ! the ierr value!!

      if (size .gt. MAXPROCS) then
         print *, "Too many processes!"
         call MPI_Finalize()
      endif
      
      write(message, '("The message from proc ",i2.2)') rank
      
      
      call MPI_Gather(message, 30, MPI_CHARACTER, 
     .             allmessages, 30, MPI_CHARACTER, root, 
     .             MPI_COMM_WORLD, ierr)

      if (rank .eq. root) then
         do i = 0,size-1
            print *, "Proc ",i, ": ", allmessages(i+1)
         enddo
      endif
      
      call MPI_Finalize(ierr)
      
      stop
      end