MPI_T_event_handle_free(3)

✨ MPI_T_event_handle_free(3) — the "okay bestie, we're done here" era of manual pages ✨

Hiii so this is a page from the MPI manual, and it's about MPI_T_event_handle_free — the little function that kicks off the deallocation of an event-registration handle. Think of it as the graceful goodbye, not the ghosting. 🫶

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💖 NAME 💖

MPI_T_event_handle_free — initiates deallocation of the event-registration handle specified by event_registration. It's giving cleanup era, it's giving closure, no cap. 🎀

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🌸 SYNOPSIS 🌸

int MPI_T_event_handle_free(MPI_T_event_registration event_registration,
void *user_data,
MPI_T_event_free_cb_function free_cb_function)

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🦋 INPUT PARAMETERS 🦋

• event_registration — the event registration, aka the handle. This is the main character of this whole operation 💅
• user_data — a pointer to a user-controlled buffer. (The docs literally say (None) here, so like… you do you, bestie.) ✨
• free_cb_function — a pointer to your very own user-defined callback function. (Listed as (function).) You bring the callback, the function brings the closure. 🔥

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🧚 THREAD AND INTERRUPT SAFETY 🧚

Okay so the thread safety tea: this routine is thread-safe. That means a bunch of threads can use it at the same time and you do not need to bring your own user-provided thread locks. Slay. 👑

But — and this is the important part — it is NOT interrupt safe. 😭 Typically that's because of memory allocation routines like malloc, or other non-MPICH runtime routines, which are themselves not interrupt-safe. So no interrupting mid-vibe, okay? Don't do it.

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⭐ ERRORS ⭐

Bestie, gather round, because this is the part where every MPI routine has ✨feelings✨.

All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value. For C routines it's the value of the function itself; for Fortran routines it lands 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 💀 — yes, fr fr, it just ends the whole thing. You can change the error handler with:

• 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 also be used, but its use is deprecated 🙈 (so like, it works, but it's not the vibe anymore).

You can also use the predefined error handler MPI_ERRORS_RETURN to make error values be returned instead of aborting.

Heads up: MPI does not guarantee that an MPI program can continue past an error. However, MPI implementations will attempt to continue whenever possible. So it's a maybe, not a promise. 😌

Now the error codes themselves, one by one, because we're thorough queens here:

• MPI_SUCCESS — no error; the MPI routine completed successfully. We love a happy ending 💖
• MPI_T_ERR_INVALID_HANDLE — the handle is invalid. Rude, but noted.
• MPI_T_ERR_NOT_INITIALIZED — the MPI tool information interface is not initialized. You gotta turn it on first, bestie 😭
• MPI_ERR_OTHER — other error; use MPI_Error_string to get more information about this error code. Mystery era 🕵️

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🌈 SEE ALSO 🌈

(Nothing extra listed on this page — it's a standalone baddie. periodt.)

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And that's the whole page, bestie!! Written through-and-through with love for the MPI manual, and this version is dated 4/10/2026. Go forth, free those event handles, and stay interrupt-safe (you're not, but go forth anyway) 💅✨🌸