MPI_SESSION_GET_PSET_INFO(3)

💖 MPI_SESSION_GET_PSET_INFO 💖

okay bestie, gather round, because we're talking about MPI_Session_get_pset_info — a lil Open MPI function from the MPI_SESSION_GET_PSET_INFO(3) page that literally just hands you an info object stuffed with the deets of one specific process set. it's giving "let me check the vibe of this pset" and honestly? obsessed. ✨

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✨ SYNTAX ✨

🎀 C Syntax

#include <mpi.h>

int MPI_Session_get_pset_info(MPI_Session session, const char *pset_name, MPI_Info *info)

🎀 Fortran Syntax

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

MPI_SESSION_GET_PSET_INFO(SESSION, PSET_NAME, INFO, IERROR)
    INTEGER SESSION, INFO, IERROR
    CHARACTER*(*) PSET_NAME

🎀 Fortran 2008 Syntax

USE mpi_f08

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

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🌸 INPUT PARAMETERS 🌸

• session — session (handle). the whole vibe holder, iykyk.
• pset_name — name of process set (string). yeah bestie, you gotta name the process set you're asking about.

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🦋 OUTPUT PARAMETERS 🦋

• info — info object (handle). this is the goodie bag you get back.
• ierror — Fortran only: Error status (integer).

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💅 DESCRIPTION 💅

MPI_Session_get_pset_info is used to query properties of a specific process set. the returned info object can be queried with existing MPI info object query functions. one key/value pair must be defined: mpi_size. the value of the mpi_size key specifies the number of MPI processes in the process set. that's the main character key right there, no cap. 👑

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⭐ NOTES ⭐

the user is responsible for freeing the returned info object via MPI_Info_free. so like… don't just leave it lying around, bestie, that's a memory leak and it's not the vibe. 🫶

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💀 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. (yes, even here. MPI said "we contain multitudes.")

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. dramatic? yes. effective? also yes. 💀
• 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. the chill one. the "we can talk about this" one. ✨

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. so like… plan accordingly, bestie. 😭

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.

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🔥 SEE ALSO 🔥

• MPI_Session_init

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👑 COPYRIGHT 👑

2003-2026, The Open MPI Community

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and that's the whole page, bestie!! this one came from the Open MPI crew — version vibes stamped Sep 10, 2026 — for MPI_SESSION_GET_PSET_INFO(3). slay, go query those process sets, and don't forget to free your info object. mwah. 💖✨🎀