MPI_OPEN_PORT(3)

💖 MPI_OPEN_PORT(3) 💖

okay bestie, gather round, because this is a page from the Open MPI manual and it's honestly kind of iconic. it's called MPI_Open_port and it's all about setting up a network address so a server can be like "hey clients, come thru 🌈".

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✨ NAME ✨

MPI_Open_port — Establishes a network address for a server to accept connections from clients.

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✨ SYNTAX ✨

🌸 C Syntax 🌸

#include <mpi.h>

int MPI_Open_port(MPI_Info info, char *port_name)

🌸 Fortran Syntax 🌸

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

🌸 Fortran 2008 Syntax 🌸

USE mpi_f08
MPI_Open_port(info, port_name, ierror)
     TYPE(MPI_Info), INTENT(IN) :: info
     CHARACTER(LEN=MPI_MAX_PORT_NAME), INTENT(OUT) :: port_name
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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✨ INPUT PARAMETER ✨

• info — the options for how to establish an address (a handle, bestie). and ngl, there are no options currently supported, so it's giving "just pass it and move on" energy 💅

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✨ OUTPUT PARAMETERS ✨

• port_name — the newly established port (a string, so cute).
• ierror — Fortran only: error status (integer).

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✨ DESCRIPTION ✨

so MPI_Open_port establishes a network address, encoded in the port_name string, at which the server will be able to accept connections from clients. and the port_name? supplied by the system. periodt. 👑

MPI copies a system-supplied port name into port_name. that port_name identifies the newly opened port, and a client can use it to contact the server. the maximum size string that may be supplied by the system is MPI_MAX_PORT_NAME. remember that, bestie, don't forget it 💖

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✨ SUPPORTED INFO KEYS ✨

None. literally none. not a single one. the info keys are not giving anything today 🙈

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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. iykyk.

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. like, everyone. the whole group chat. 💀
• 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. lowkey the polite 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… don't count on it, 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.

See also:

• MPI_Comm_accept
• MPI_Comm_connect

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🎀 Copyright 🎀

2003-2026, The Open MPI Community

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and that's the whole page, bestie 💅✨ this was MPI_OPEN_PORT(3) from the Open MPI manual, and the footer said Sep 10, 2026 — so go forth, open those ports, and slay responsibly 👑💖🦋