MPI_SSEND(3)

💖 MPI_Ssend — bestie's guide to the synchronous send 💖

okay so this is the Open MPI page for MPI_Ssend(3), aka the standard synchronous send. pull up a chair, we're doing blocking comms today 🫶

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✨ NAME ✨

MPI_Ssend — Standard synchronous send.

🦋 SYNTAX 🦋

C Syntax

#include <mpi.h>

int MPI_Ssend(const void *buf, int count, MPI_Datatype datatype, int dest,
     int tag, MPI_Comm comm)

Fortran Syntax

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

Fortran 2008 Syntax

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

🎀 INPUT PARAMETERS 🎀

• buf — Initial address of send buffer (choice). it's giving "here's my stuff, take it" 📦
• count — Number of elements in send buffer (nonnegative integer). pls keep it nonnegative bestie, negative counts are not the vibe 💅
• datatype — Datatype of each send buffer element (handle).
• dest — Rank of destination (integer). who's getting the message 👀
• tag — Message tag (integer).
• comm — Communicator (handle).

🌸 OUTPUT PARAMETER 🌸

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

🌈 DESCRIPTION 🌈

So MPI_Ssend performs a synchronous-mode, blocking send. that's the whole personality fr fr ✨

if you want the deep lore about such sends, go read the MPI Standard <https://www.mpi-forum.org/docs/> — it has all the detailed information about synchronous sends. this page is just the vibe summary, the standard is the full novel 📚

💀 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 — C hands it back to you, Fortran drops it in that last slot 🫠

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. the nuclear option, rip to everyone 💀
• 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. read that again bestie — no guarantee, so don't be out here acting like you can just keep vibing after 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.

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👑 Copyright 👑

2003-2026, The Open MPI Community

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and that's the whole page, no cap 🎀 ty for reading my little MPI_SSEND(3) essay — this one shipped with Open MPI, dated Sep 10, 2026, and now you know synchronous sends and you can go slay some parallel code. periodt 💅✨