SYNTAX

   C Syntax
          #include <mpi.h>

          int MPI_Lookup_name(const char *service_name, MPI_Info info,
               char *port_name)

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'
          MPI_LOOKUP_NAME(SERVICE_NAME, INFO, PORT_NAME, IERROR)
               CHARACTER*(*)   SERVICE_NAME, PORT_NAME
               INTEGER         INFO, IERROR

   Fortran 2008 Syntax
          USE mpi_f08
          MPI_Lookup_name(service_name, info, port_name, ierror)
               CHARACTER(LEN=*), INTENT(IN) :: service_name
               TYPE(MPI_Info), INTENT(IN) :: info
               CHARACTER(LEN=MPI_MAX_PORT_NAME), INTENT(OUT) :: port_name
               INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

       • service_name: A service name (string).

       • info: Options to the name service functions (handle).

OUTPUT PARAMETERS

       • port_name: a port name (string).

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

DESCRIPTION

       This   function  retrieves  a  port_name  published  under  service_name  by  a  previous  invocation  of
       MPI_Publish_name. The application must supply a  port_name  buffer  large  enough  to  hold  the  largest
       possible port name (i.e., MPI_MAX_PORT_NAME bytes).

INFO ARGUMENTS

       The following keys for info are recognized:

          Key                   Type      Description
          ---                   ----      -----------

          ompi_lookup_order     char *    Resolution order for name lookup.

       The  ompi_lookup_order  info  key can specify one of four valid string values (see the NAME SCOPE section
       below for more information on name scopes):

       local: Only search the local scope for name resolution.

       global: Only search the global scope for name resolution.

       local,global: Search the local scope for name resolution. If
              not found, try searching the global scope for name resolution. This behavior is the default if the
              ompi_lookup_order info key is not specified.

       global,local: Search the global scope for name resolution. If
              not found, try searching the local scope for name resolution.

       If no info key is provided, the search will first check to see if a global server has been specified  and
       is  available.  If  so, then the search will default to global scope first, followed by local. Otherwise,
       the search will default to local.

NAME SCOPE

       Open MPI supports two name scopes: global and local. Local scope  values  are  placed  in  a  data  store
       located  on the mpirun of the calling process’ job, while global scope values reside on a central server.
       Calls to MPI_Unpublish_name must correctly specify the scope to be  used  in  finding  the  value  to  be
       removed.  The  function  will return an error if the specified service name is not found on the indicated
       location.

       For a more detailed description of scoping rules, please see the MPI_Publish_name man page.

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_Publish_name

          • MPI_Open_port

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                                MPI_LOOKUP_NAME(3)