MPI_PREADY_RANGE(3)

💖 MPI_Pready_range 💖

okay so bestie, welcome to the manual page for MPI_Pready_range, which lives in the MPI_PREADY_RANGE(3) section of the Open MPI docs. this little icon tells the world that a whole range of send-side partitions are ready to be shipped out. like, "these ones are done, come get em" energy. no cap. 🫶

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✨ NAME ✨

MPI_Pready_range — signals that a given range of send-side partitions are ready to be transferred. 💌

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🌸 SYNTAX 🌸

🎀 C Syntax

#include <mpi.h>

int MPI_Pready_range(int partition_low, int partition_high, MPI_Request request)

🎀 Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_PREADY(PARTITION_LOW, PARTITION_HIGH, REQUEST, IERROR)
     INTEGER PARTITION_LOW, PARTITION_HIGH, REQUEST, IERROR

🎀 Fortran 2008 Syntax

USE mpi_f08
MPI_Pready(partition_low, partition_high, request, ierror)
     INTEGER, INTENT(IN) :: partition_low, partition_high
     TYPE(MPI_Request), INTENT(IN) :: request
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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🦋 INPUT PARAMETERS 🦋

• partition_low — the lowest partition in the range you're marking as ready to transfer. it's an integer, bestie. 💅
• partition_high — the highest partition in that range. also an integer. 📈
• request — your communication request, aka the handle. 🎯

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🌈 OUTPUT PARAMETERS 🌈

• ierror — Fortran only: the error status (integer). 🧾

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👑 ERRORS 👑

okay so real talk: almost every MPI routine gives you back an error value. in C it's the return value of the function, and in Fortran it lands in the last argument. 💀

but before that error value comes back to you, the current MPI error handler attached to the communication object (think: communicator, window, file) gets called. and if there's no communication object tied to that MPI call at all? then the call is considered attached to MPI_COMM_SELF and it'll call the error handler for that. and when MPI_COMM_SELF isn't even initialized yet — meaning before MPI_Init / MPI_Init_thread, after MPI_Finalize, or when you're using the Sessions Model exclusively — then the error raises the initial error handler. 🌱

you can change that initial error handler, btw, by calling MPI_Comm_set_errhandler on MPI_COMM_SELF if you're in the World model, or via the mpi_initial_errhandler CLI argument to mpiexec, or with the info key to MPI_Comm_spawn / MPI_Comm_spawn_multiple. and if no other appropriate error handler has been set? then MPI_ERRORS_RETURN gets called for MPI I/O functions, and MPI_ERRORS_ABORT gets called for all the other MPI functions. 😭

Open MPI ships three predefined error handlers you can use:

• MPI_ERRORS_ARE_FATAL — causes the program to abort all connected MPI processes. dramatic, but it's giving decisive. 💀
• MPI_ERRORS_ABORT — an error handler that can be invoked on a communicator, window, file, or session. when you call it on a communicator, it acts as if MPI_Abort was called on that communicator. call it on a window or file and it acts as if MPI_Abort was called on a communicator containing the group of processes in the corresponding window or file. call it on a session and it aborts only the local process. 🌪️
• MPI_ERRORS_RETURN — hands an error code back to your application. 🫶

MPI applications can also implement their very own error handlers by calling:

• MPI_Comm_create_errhandler and then MPI_Comm_set_errhandler 🛠️
• MPI_File_create_errhandler and then MPI_File_set_errhandler 📁
• MPI_Session_create_errhandler and then MPI_Session_set_errhandler, or at MPI_Session_init 🌀
• MPI_Win_create_errhandler and then MPI_Win_set_errhandler 🪟

⚠️ note that MPI does not guarantee that an MPI program can continue past an error. like, once it's over it's over, periodt.

see the MPI man page for a full list of MPI error codes. 📜

and see the Error Handling section of the MPI-3.1 standard if you want the deep lore. 📚

see also:

• MPI_Pready
• MPI_Pready_list
• MPI_Parrived

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🎀 Copyright 🎀

2003-2026, The Open MPI Community 💜

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okay bestie that's the whole page!! 🥳 this was MPI_PREADY_RANGE(3) from Open MPI, dated Sep 10, 2026 — go mark those partitions ready and slay, you've got this 💅✨🦋🍓