1: #include <petsc/private/viewerimpl.h>
  2: #include <petscviewersaws.h>

  4: /*
  5:     The variable Petsc_Viewer_SAWs_keyval is used to indicate an MPI attribute that
  6:   is attached to a communicator, in this case the attribute is a PetscViewer.
  7: */
  8: static PetscMPIInt Petsc_Viewer_SAWs_keyval = MPI_KEYVAL_INVALID;

 10: /*@
 11:      PETSC_VIEWER_SAWS_ - Creates a SAWs `PetscViewer` shared by all MPI processes in a communicator.

 13:      Collective

 15:      Input Parameter:
 16: .    comm - the MPI communicator to share the `PetscViewer`

 18:      Level: developer

 20:      Note:
 21:      Unlike almost all other PETSc routines, `PETSC_VIEWER_SAWS_()` does not return
 22:      an error code.  The resulting `PetscViewer` is usually used in the form
 23: .vb
 24:      XXXView(XXX object, PETSC_VIEWER_SAWS_(comm));
 25: .ve

 27: .seealso: [](sec_viewers), `PetscViewer`, `PETSC_VIEWER_SAWS_WORLD`, `PETSC_VIEWER_SAWS_SELF`
 28: @*/
 29: PetscViewer PETSC_VIEWER_SAWS_(MPI_Comm comm)
 30: {
 31:   PetscErrorCode ierr;
 32:   PetscMPIInt    iflg;
 33:   PetscViewer    viewer;
 34:   MPI_Comm       ncomm;

 36:   PetscFunctionBegin;
 37:   PetscCallNull(PetscCommDuplicate(comm, &ncomm, NULL));
 38:   if (Petsc_Viewer_SAWs_keyval == MPI_KEYVAL_INVALID) PetscCallMPINull(MPI_Comm_create_keyval(MPI_COMM_NULL_COPY_FN, MPI_COMM_NULL_DELETE_FN, &Petsc_Viewer_SAWs_keyval, 0));
 39:   ierr = (PetscErrorCode)MPI_Comm_get_attr(ncomm, Petsc_Viewer_SAWs_keyval, (void **)&viewer, &iflg);
 40:   if (ierr) {
 41:     ierr = PetscError(ncomm, __LINE__, "PETSC_VIEWER_SAWS_", __FILE__, PETSC_ERR_MPI, PETSC_ERROR_INITIAL, " ");
 42:     PetscFunctionReturn(NULL);
 43:   }
 44:   if (!iflg) { /* PetscViewer not yet created */
 45:     PetscCallNull(PetscViewerSAWsOpen(comm, &viewer));
 46:     PetscCallNull(PetscObjectRegisterDestroy((PetscObject)viewer));
 47:     ierr = (PetscErrorCode)MPI_Comm_set_attr(ncomm, Petsc_Viewer_SAWs_keyval, (void *)viewer);
 48:     if (ierr) {
 49:       ierr = PetscError(ncomm, __LINE__, "PETSC_VIEWER_SAWS_", __FILE__, PETSC_ERR_MPI, PETSC_ERROR_INITIAL, " ");
 50:       PetscFunctionReturn(NULL);
 51:     }
 52:   }
 53:   PetscCallNull(PetscCommDestroy(&ncomm));
 54:   PetscFunctionReturn(viewer);
 55: }

 57: static PetscErrorCode PetscViewerDestroy_SAWs(PetscViewer viewer)
 58: {
 59:   PetscFunctionBegin;
 60:   /*
 61:      Make sure that we mark that the stack is no longer published
 62:   */
 63:   if (PetscObjectComm((PetscObject)viewer) == PETSC_COMM_WORLD) PetscCall(PetscStackSAWsViewOff());
 64:   PetscFunctionReturn(PETSC_SUCCESS);
 65: }

 67: PETSC_EXTERN PetscErrorCode PetscViewerCreate_SAWs(PetscViewer v)
 68: {
 69:   PetscFunctionBegin;
 70:   v->ops->destroy = PetscViewerDestroy_SAWs;
 71:   PetscFunctionReturn(PETSC_SUCCESS);
 72: }