MPI_TYPE_SET_ATTR(3)

💅 MPI_TYPE_SET_ATTR(3) — like, the Open MPI manual page, bestie ✨

okay so this is the MPI_TYPE_SET_ATTR page from Open MPI, and it's literally about attaching attribute vibes to datatypes. let's get into it 🎀

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🌸 NAME 🌸

MPI_Type_set_attr — sets a key value/attribute pair to a data type. that's it. that's the whole job. iconic of it honestly 🫶

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✨ SYNTAX ✨

💜 C Syntax

#include <mpi.h>

int MPI_Type_set_attr(MPI_Datatype type, int type_keyval,
     void *attribute_val)

💜 Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_TYPE_SET_ATTR(TYPE, TYPE_KEYVAL, ATTRIBUTE_VAL, IERROR)
     INTEGER TYPE, TYPE_KEYVAL, IERROR
     INTEGER(KIND=MPI_ADDRESS_KIND) ATTRIBUTE_VAL

💜 Fortran 2008 Syntax

USE mpi_f08
MPI_Type_set_attr(datatype, type_keyval, attribute_val, ierror)
     TYPE(MPI_Datatype), INTENT(IN) :: datatype
     INTEGER, INTENT(IN) :: type_keyval
     INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: attribute_val
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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🔄 INPUT/OUTPUT PARAMETER 🔄

• type — the data type we're attaching the attribute to (it's a handle). yes bestie it's both input and output, she contains multitudes 💅

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🧚 INPUT PARAMETERS 🧚

• type_keyval — the key value (an integer). the little name-tag for your attribute fr fr.
• attribute_val — the attribute value itself. the actual content. the main character 🌟

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🦋 OUTPUT PARAMETER 🦋

• ierror — Fortran only: the error status (integer). Fortran girlies get their errors handed to them in the last argument, no cap.

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💖 DESCRIPTION 💖

so for the given data type, MPI_Type_set_attr sets the key value to the value of the specified attribute. that's the tea ☕ — key value in, attribute value attached, slay.

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😭 ERRORS 😭

almost all MPI routines return an error value, okay? C routines give it back as the return result of the function, and Fortran routines put it in that last argument. both valid, both slay 💅

before the error value gets returned, the current MPI error handler associated with the communication object (think: communicator, window, file) gets called. and if there's no communication object associated with the MPI call? then the call gets treated as attached to MPI_COMM_SELF and it calls the associated MPI error handler. periodt.

when MPI_COMM_SELF is not initialized (i.e., before MPI_Init/MPI_Init_thread, after MPI_Finalize, or when you're using the Sessions Model exclusively) the error raises the initial error handler. and you can change that initial error handler:

• by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using the World model, or
• with 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 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. that's just how it is 🫠

Open MPI ships three predefined error handlers you can use:

• MPI_ERRORS_ARE_FATAL — causes the program to abort all connected MPI processes. like, everyone. dramatic but effective 💀
• 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, it 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, it aborts only the local process. versatile queen 👑
• MPI_ERRORS_RETURN — returns an error code to the application. the chill 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. like, no promises bestie, be careful out there 🙈

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 for more information. iykyk 📚

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👀 SEE ALSO: 👀

• MPI_Type_get_attr

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🎀 COPYRIGHT 🎀

2003-2026, The Open MPI Community

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and that's the whole page, bestie!! 🦋✨ this was Open MPI, MPI_TYPE_SET_ATTR(3), dated Sep 11, 2026 — go forth and attach those attributes, you absolute icon 💖🍓👑