MPI_Status_set_elements(3)

💖 MPI_Status_set_elements(3) — the MPI girlie edition 💖

okay bestie, this is MPI_Status_set_elements from the MPI manual, and it's literally the glow-up your status object has been waiting for ✨

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🌸 NAME 🌸

MPI_Status_set_elements — set the number of elements in a status 💅

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✨ SYNOPSIS ✨

int MPI_Status_set_elements(MPI_Status *status, MPI_Datatype datatype,
int count)

int MPI_Status_set_elements_c(MPI_Status *status, MPI_Datatype datatype,
MPI_Count count)

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🎀 INPUT PARAMETERS 🎀

• datatype — the datatype that's besties with count (it's a handle, iykyk)
• count — how many elements you wanna associate with status (an integer, no cap)

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🦋 INPUT/OUTPUT PARAMETERS 🦋

• status — the status we're associating count with (a Status) 🫶

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🔥 THREAD AND INTERRUPT SAFETY 🔥

This routine is thread-safe. That means multiple threads can use it at the same time, zero user-provided thread locks needed. She's responsible like that 💅

BUT — and this is the part where we get real — she's not interrupt safe. Typically that's because of memory allocation routines like malloc, or other non-MPICH runtime routines, that are themselves not interrupt-safe. So like… don't come for her, it's not her fault 😭

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💜 NOTES FOR FORTRAN 💜

All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK) have an extra argument ierr at the end of the argument list. ierr is an integer and it means the exact same thing as the return value of the routine in C. In Fortran, MPI routines are subroutines and you invoke them with the call statement. periodt.

Also, all MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type INTEGER in Fortran. yes fr fr.

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😭 ERRORS 😭

Every MPI routine (except MPI_Wtime and MPI_Wtick) returns an error value — C routines give it back as the value of the function, and Fortran routines stick it in the last argument. Before that value comes back, the current MPI error handler gets called. By default, this error handler aborts the MPI job 💀. If you want to change it:

• MPI_Comm_set_errhandler — for communicators
• MPI_File_set_errhandler — for files
• MPI_Win_set_errhandler — for RMA windows

The MPI-1 routine MPI_Errhandler_set may be used but its use is deprecated, so like… don't.

The predefined error handler MPI_ERRORS_RETURN can be used to make error values get returned instead.

⚠️ Note that MPI does not guarantee that an MPI program can continue past an error. However, MPI implementations will attempt to continue whenever possible. she's doing her best 🙈

Here's the error code menu, babe:

• MPI_SUCCESS — no error; the MPI routine completed successfully 👑
• MPI_ERR_ARG — invalid argument. Some argument is invalid and isn't identified by a specific error class (e.g., MPI_ERR_RANK).
• MPI_ERR_COUNT — invalid count argument. Count arguments must be non-negative; a count of zero is often valid 🌈
• MPI_ERR_TYPE — invalid datatype argument. Also, this error can occur if an uncommitted MPI_Datatype (see MPI_Type_commit) is used in a communication call.
• MPI_ERR_OTHER — other error; use MPI_Error_string to get more information about this error code 🍓

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and that's the whole page, bestie! go set those elements, you main character 🧚✨

mwah 💋 — this lil guide was served up from the MPI 4/10/2026 drop.