MPI_SESSION_GET_NTH_PSET(3)

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version 5.0.10 · 4 versions
, in ubuntu stonking

💖 MPI_SESSION_GET_NTH_PSET 💖

okay bestie, gather round — this is the MPI_SESSION_GET_NTH_PSET(3) page from the Open MPI girlies, and it's literally about asking the runtime "hey what's the name of the nth process set?" and getting your answer back in a buffer. no cap. 🦋

🌸 NAME 🌸

MPI_Session_get_nth_pset — query runtime for name of the nth process set ✨

💅 SYNTAX 💅

✨ C Syntax ✨

#include <mpi.h>

int MPI_Session_get_nth_pset(MPI_Session session, MPI_Info info, int n, int *pset_len, char *pset_name)

🎀 Fortran Syntax 🎀

USE MPI
! or the older form: INCLUDE 'mpif.h'

MPI_SESSION_GET_NTH_PSET(SESSION, INFO, N, PSET_LEN, PSET_NAME, IERROR)
    INTEGER SESSION, INFO, N, PSET_LEN, IERROR
    CHARACTER*(*) PSET_NAME

🦋 Fortran 2008 Syntax 🦋

USE mpi_f08

MPI_Session_get_nth_pset(session, info, n, pset_len, pset_name, ierror)
    TYPE(MPI_Session), INTENT(IN) :: session
    TYPE(MPI_Info), INTENT(IN) :: info
    INTEGER, INTENT(IN) :: n
    INTEGER, INTENT(INOUT) :: pset_len
    CHARACTER(LEN=*), INTENT(OUT) :: pset_name
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror

🫶 INPUT PARAMETERS 🫶

  • session : session (handle) — the session, obvi 💜
  • info : info object (handle) — your info object 🌸
  • n : index of the desired process set name (integer) — which one you want, starting from the *n*th 🎀

💫 INPUT/OUTPUT PARAMETER 💫

  • pset_len : length of the pset_name argument (integer) — it goes in, it comes out, main character energy 🔥

👑 OUTPUT PARAMETERS 👑

  • pset_name : name of the nth process set (string) — there she is ✨
  • ierror : Fortran only: Error status (integer). 🍓

🌈 DESCRIPTION 🌈

okay so MPI_Session_get_nth_pset returns the name of the *n*th process set in the supplied pset_name buffer. that's the whole vibe.

pset_len is the size of the buffer needed to store the *n*th process set name. and listen — if the pset_len you passed in is less than the actual buffer size needed for the process set name, then the string value returned in pset_name gets truncated. 😭 yeah. if pset_len is set to 0, then pset_name is not changed at all. not even a little.

on return, the value of pset_len will be set to the required buffer size to hold the process set name. in C, pset_len includes the required space for the null terminator. also in C, this function returns a null terminated string in all cases where the pset_len input value is greater than 0. periodt. 💅

🧚 NOTES 🧚

Process set names have an implementation-defined maximum length of MPI_MAX_PSET_NAME_LEN characters. MPI_MAX_PSET_NAME_LEN shall have a value of at least 63. ⭐

💀 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. 😭 fr fr, keep that in mind.

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_Session_init 🌟

2003-2026, The Open MPI Community

and that's the whole page, bestie 🎀✨ it's giving Open MPI, dated Sep 10, 2026, and it says MPI_SESSION_GET_NTH_PSET(3) at the bottom too, so you know exactly what you were reading. slay. 💖🦋🌸

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