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

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

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

 14:      Collective

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

 19:      Level: developer

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

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

 37:   PetscFunctionBegin;
 38:   PetscCallNull(PetscCommDuplicate(comm, &ncomm, NULL));
 39:   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)); }
 40:   ierr = (PetscErrorCode)MPI_Comm_get_attr(ncomm, Petsc_Viewer_SAWs_keyval, (void **)&viewer, &flag);
 41:   if (ierr) {
 42:     ierr = PetscError(ncomm, __LINE__, "PETSC_VIEWER_SAWS_", __FILE__, PETSC_ERR_MPI, PETSC_ERROR_INITIAL, " ");
 43:     PetscFunctionReturn(NULL);
 44:   }
 45:   if (!flag) { /* PetscViewer not yet created */
 46:     PetscCallNull(PetscViewerSAWsOpen(comm, &viewer));
 47:     PetscCallNull(PetscObjectRegisterDestroy((PetscObject)viewer));
 48:     ierr = (PetscErrorCode)MPI_Comm_set_attr(ncomm, Petsc_Viewer_SAWs_keyval, (void *)viewer);
 49:     if (ierr) {
 50:       ierr = PetscError(ncomm, __LINE__, "PETSC_VIEWER_SAWS_", __FILE__, PETSC_ERR_MPI, PETSC_ERROR_INITIAL, " ");
 51:       PetscFunctionReturn(NULL);
 52:     }
 53:   }
 54:   PetscCallNull(PetscCommDestroy(&ncomm));
 55:   PetscFunctionReturn(viewer);
 56: }

 58: static PetscErrorCode PetscViewerDestroy_SAWs(PetscViewer viewer)
 59: {
 60:   PetscFunctionBegin;
 61:   /*
 62:      Make sure that we mark that the stack is no longer published
 63:   */
 64:   if (PetscObjectComm((PetscObject)viewer) == PETSC_COMM_WORLD) PetscCall(PetscStackSAWsViewOff());
 65:   PetscFunctionReturn(PETSC_SUCCESS);
 66: }

 68: PETSC_EXTERN PetscErrorCode PetscViewerCreate_SAWs(PetscViewer v)
 69: {
 70:   PetscFunctionBegin;
 71:   v->ops->destroy = PetscViewerDestroy_SAWs;
 72:   PetscFunctionReturn(PETSC_SUCCESS);
 73: }