SYNTAX

   C Syntax
          #include <mpi.h>

          int MPI_Comm_set_info(MPI_Comm comm, MPI_Info info)

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'
          MPI_COMM_SET_INFO(COMM, INFO, IERROR)
               INTEGER COMM, INFO, IERROR

   Fortran 2008 Syntax
          USE mpi_f08
          MPI_Comm_set_info(comm, info, ierror)
               TYPE(MPI_Comm), INTENT(IN) :: comm
               TYPE(MPI_Info), INTENT(IN) :: info
               INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

       • comm: Communicator on which to set info hints

       • info: Info object containing hints to be set on comm

OUTPUT PARAMETERS

       • ierror: Fortran only: Error status (integer).

DESCRIPTION

       MPI_Comm_set_info   sets   new   values   for  the  hints  of  the  communicator  associated  with  comm.
       MPI_Comm_set_info is a collective routine. The info object may be different on each process, but any info
       entries that an implementation requires to be the same on all processes must appear with the  same  value
       in each process’s info object.

       The following info key assertions may be accepted by Open MPI:

       mpi_assert_no_any_tag (boolean): If set to true, then the implementation may assume that the process will
       not use the MPI_ANY_TAG wildcard on the given communicator.

       mpi_assert_no_any_source  (boolean):  If set to true, then the implementation may assume that the process
       will not use the MPI_ANY_SOURCE wildcard on the given communicator.

       mpi_assert_exact_length (boolean): If set to true, then the implementation may assume that the lengths of
       messages received by the process are equal to the lengths  of  the  corresponding  receive  buffers,  for
       point-to-point communication operations on the given communicator.

       mpi_assert_allow_overtaking  (boolean):  If  set  to  true,  then  the  implementation  may  assume  that
       point-to-point communications on the given communicator do not rely on the non-overtaking rule  specified
       in  MPI-3.1 Section 3.5. In other words, the application asserts that send operations are not required to
       be matched at the receiver in the order in which the send operations were performed by  the  sender,  and
       receive  operations  are  not  required  to  be  matched in the order in which they were performed by the
       receiver.

ERRORS

       Almost all MPI routines return an error value; C routines as  the  return  result  of  the  function  and
       Fortran routines in the last argument.

       Before  the  error  value  is  returned,  the current MPI error handler associated with the communication
       object (e.g., communicator, window, file) is called.  If no communication object is associated  with  the
       MPI  call,  then  the call is considered attached to MPI_COMM_SELF and will call the associated MPI error
       handler.  When  MPI_COMM_SELF  is  not  initialized   (i.e.,   before   MPI_Init/MPI_Init_thread,   after
       MPI_Finalize,  or  when using the Sessions Model exclusively) the error raises the initial error handler.
       The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF  when  using
       the  World  model,  or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/‐
       MPI_Comm_spawn_multiple.  If no other appropriate error handler has been set, then the  MPI_ERRORS_RETURN
       error  handler  is  called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all
       other MPI functions.

       Open MPI includes three predefined error handlers that can be used:

       • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

       • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When
         called on a communicator, it acts as if MPI_Abort was called on  that  communicator.  If  called  on  a
         window  or file, acts as if MPI_Abort was called on a communicator containing the group of processes in
         the corresponding window or file. If called on a session, aborts only the local process.

       • MPI_ERRORS_RETURN Returns an error code to the application.

       MPI applications can also implement their own error handlers by calling:

       • MPI_Comm_create_errhandler then MPI_Comm_set_errhandler

       • MPI_File_create_errhandler then MPI_File_set_errhandler

       • MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init

       • MPI_Win_create_errhandler then MPI_Win_set_errhandler

       Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.

       See the Error Handling section of the MPI-3.1 standard for more information.

       SEE ALSO:

          • MPI_Comm_get_info

          • MPI_Info_create

          • MPI_Info_set

          • MPI_Info_free

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                              MPI_COMM_SET_INFO(3)