MPI_T_event_callback_get_info(3)

💖 MPI_T_event_callback_get_info(3) 💖

okay bestie, welcome to the <pink>MPI</pink> manual page for MPI_T_event_callback_get_info — yes the name is a whole mouthful, we're gonna get through it together 🫶

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✨ NAME ✨

MPI_T_event_callback_get_info — returns a new info object containing the hints of the callback function registered for the callback safety level specified by cb_safety of the event-registration handle associated with event_registration.

like. it hands you a fresh MPI_Info full of the hints that belong to whichever callback got registered at that safety level. that's the whole vibe 💅

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🌸 SYNOPSIS 🌸

int MPI_T_event_callback_get_info(MPI_T_event_registration event_registration,
MPI_T_cb_safety cb_safety,
MPI_Info *info_used)

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🎀 INPUT PARAMETERS 🎀

• event_registration — event registration (handle). yeah it's a handle, that's it, that's the tea 🍓
• cb_safety — callback safety level (integer). an integer, no cap.

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🦋 OUTPUT PARAMETERS 🦋

• info_used — info object (handle). this is where the new info lands, bestie.

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💅 THREAD AND INTERRUPT SAFETY 💅

okay so this routine is thread-safe ✨ which literally means multiple threads can use it at the same time and you do not need to bring your own thread locks. no user-provided locking, none, it's handled.

BUT — and this is the important part, don't skip it 😭 — the routine is not interrupt safe. typically that's because it uses memory allocation routines like malloc (or other non-MPICH runtime routines) and those are themselves not interrupt-safe. so it's giving "safe with your friends, not safe when interrupted mid-sentence" energy 💀

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🌈 ERRORS 🌈

okay bestie, general rules first, because every MPI routine plays by these:

all MPI routines (except MPI_Wtime and MPI_Wtick) return an error value. C routines return it as the value of the function, and Fortran routines put it in the last argument. before that value comes back, the current MPI error handler gets called. by default, that error handler aborts the MPI job 🚨 (yes, dramatic, that's just how it is).

the error handler can be changed 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 be used, but its use is deprecated 🚫 (pls don't, it's so last era).

the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be 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. so like... maybe? 🙈

and here are the actual error codes, in order:

• MPI_SUCCESS — no error; MPI routine completed successfully. the dream, the icon 👑
• MPI_T_ERR_INVALID — invalid use of the interface or bad parameter values(s).
• MPI_T_ERR_INVALID_HANDLE — the handle is invalid. 💀
• MPI_T_ERR_NOT_INITIALIZED — the MPI tool information interface is not initialized. did you even init, bestie 😭
• 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, no skips, no missing flags, we ate and left zero crumbs 💅✨

this absolute gem is MPI_T_event_callback_get_info(3) from the MPI manual, dated 4/10/2026. go forth and get that info object, bestie 🫶🎀🌈