NAME

       pvm_siblings  -   return  the number and associated task ids of processes that were started together in a
       single spawn call.

SYNOPSIS

       C    int ntids = pvm_siblings( int **tids )

       Fortran   call pvmfsiblings( ntids, index, sibling )

PARAMETERS

       ntids   Returns the number of tids that were spawned together. Value less than 0 indicates an error.

       tids    Pointer to the array of tids that contains the siblings. Indexed from 0 to (ntids - 1)

       index   Integer index of tid to be returned in sibling. If index is set to -1, then sibling is unchanged.
               Otherwise, must be in the range [0, ntids - 1]

       sibling When index is in the range [0, ntids -1], this contains the tid of the desired index.

DESCRIPTION

       The routine pvm_siblings returns the number of tasks and a list  of  task  ids  of  processes  that  were
       spawned  together  in  a  single  spawn  call. The spawning task multicasts the list of successful to the
       spawned tasks so that each task has an identical copy of  the  sibling  list.   pvm_siblings  uses  local
       storage  to  keep  the  list  of  tids  and does not update this list when sibling tasks exit the virtual
       machine.  The FORTRAN version allows calling programs read a particular index  in  the  internal  sibling
       array.  If pvm_siblings is successful, ntids will be  > 0. If some error occurs then ntids will be < 0.

       pvm_siblings  is  designed  to  simplify  the  logic  in  static  spmd-style programs. By giving tasks an
       identical list of tids and its size, programs may self size and treat the sibling as static  map  between
       instances  and  tasks.  The  internal list is not updated when sibling tasks exit the virtual machine and
       should be treated as a snapshot of the parallel program when it was first started.

       If a task was started by pvm_spawn, then pvm_siblings will return ntids = 1 and

       ntids = 1 and tids will contain a single entry identical to the task id returned by pvm_mytid()

EXAMPLES

       C:
            int *tids;
            ntids = pvm_siblings(&tids);

       Fortran:
            INTEGER TIDS(0:MAXNPROC)
            CALL PVMFSIBLINGS(NTIDS, -1, IDUM)
            DO I = 0, NTIDS-1
               CALL PVMFSIBLINGS(NTIDS, I, TIDS(I))

ERRORS

       pvm_siblings can return the following error codes

       PvmNoTask
              No task at that index, or index is invalid.

SEE ALSO

       pvm_spawn(3PVM), pvm_mytid(3PVM), pvm_parent(3PVM)

                                                  26 June, 1997                                   SIBLINGS(3PVM)