MPI_RSEND_INIT(3)

💅 MPI_RSEND_INIT(3) 💅

okay bestie, welcome to the Open MPI manual. This page is serving MPI_Rsend_init, and it Builds a handle for a ready send. Persistent-request energy only, no one-shot chaos. 💖

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🛠️ SYNTAX 🛠️

C Syntax

#include <mpi.h>

int MPI_Rsend_init(const void *buf, int count, MPI_Datatype datatype,
     int dest, int tag, MPI_Comm comm, MPI_Request *request)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_RSEND_INIT(BUF, COUNT, DATATYPE, DEST, TAG, COMM, REQUEST,
             IERROR)
     <type>  BUF(*)
     INTEGER COUNT, DATATYPE, DEST, TAG, COMM, REQUEST, IERROR

Fortran 2008 Syntax

USE mpi_f08
MPI_Rsend_init(buf, count, datatype, dest, tag, comm, request, ierror)
     TYPE(*), DIMENSION(..), INTENT(IN), ASYNCHRONOUS :: buf
     INTEGER, INTENT(IN) :: count, dest, tag
     TYPE(MPI_Datatype), INTENT(IN) :: datatype
     TYPE(MPI_Comm), INTENT(IN) :: comm
     TYPE(MPI_Request), INTENT(OUT) :: request
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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📥 INPUT PARAMETERS 📥

• buf — initial address of send buffer (choice). This is where your data starts, bestie. ✨
• count — number of elements sent (integer).
• datatype — type of each element (handle).
• dest — rank of destination (integer).
• tag — message tag (integer).
• comm — communicator (handle).

📤 OUTPUT PARAMETERS 📤

• request — communication request (handle). Obsessed with a handle that knows things for you. 💅
• ierror — Fortran only: error status (integer).

💌 DESCRIPTION 💌

This creates a persistent communication object for a ready mode send operation, and binds to it all the arguments of a send operation. It’s giving “set it up once, slay later.” 🎀

A communication (send or receive) that uses a persistent request is initiated by the function MPI_Start. That’s the kickoff, no cap. 🔥

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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. 🫶

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. Like, this is a real warning, bestie — not me being dramatic. ⚠️

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_Bsend_init
• MPI_Send_init
• MPI_Ssend_init
• MPI_Recv_init
• MPI_Start
• MPI_Startall
• MPI_Request_free

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📜 COPYRIGHT 📜

2003-2026, The Open MPI Community — they made this, and we respect the icon behavior. 👑💖

byeee, you’ve reached the end of the Open MPI manual page MPI_RSEND_INIT(3), dated Sep 11, 2026 🌈🦋💜