MPIX_Request_is_complete(3)

💖 NAME 💖

MPIX_Request_is_complete — [short description] ✨

okay so hi bestie, welcome to the MPI manual, this one's a little cutie from the MPI section (yes, section 3, the library-calls girlies) 💅

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🌸 SYNOPSIS 🌸

int MPIX_Request_is_complete(MPI_Request request)

that's it. that's the whole vibe. one argument, one return, slay 🫶

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🎀 INPUT PARAMETERS 🎀

• request — communication request (handle) 🦋

like. hand me your request handle and I'll look at it. that's the whole deal.

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✨ THREAD AND INTERRUPT SAFETY ✨

good news first: this routine is thread-safe. like, genuinely. it can be used by multiple threads at the same time and you do not need to bring your own thread locks, no user-provided locking required, we're self-sufficient 💖

but — and I need you to hear me on this — it is not interrupt safe. 😭 the reason is typically the use of memory allocation routines such as malloc, or other non-MPICH runtime routines that are themselves not interrupt-safe. so like. thread-safe? yes. interrupt-safe? absolutely not. two different things bestie, do not conflate them 💀

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🌈 NOTES FOR FORTRAN 🌈

fortran girlies, this part is for you 💜

• Every MPI routine in Fortran (except for MPI_WTIME and MPI_WTICK) has one extra argument called ierr stuck on the end of the argument list. 😌
• ierr is an integer, and it means exactly the 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.
• All MPI objects (e.g. MPI_Datatype, MPI_Comm) are of type INTEGER in Fortran. periodt. 🎀

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🔥 ERRORS 🔥

okay so every MPI routine (except MPI_Wtime and MPI_Wtick) returns an error value — C routines hand it back as the value of the function, and Fortran routines put it in the last argument. 👑

but BEFORE that value comes back, the current MPI error handler gets called. and by default? that error handler aborts the MPI job. 😭 not a vibe check you want to fail.

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. 🙈

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. 💫

here's your error roster:

• MPI_SUCCESS — No error; MPI routine completed successfully. 🥳 iconic. ate.
• MPI_ERR_OTHER — Other error; use MPI_Error_string to get more information about this error code. 🔍

fr fr, if you see MPI_ERR_OTHER and you're just sitting there like ??? — go call MPI_Error_string. she will tell you what happened. that's her whole job. 🫶

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💌 SEE ALSO 💌

not me checking for a SEE ALSO section… there isn't one in this page bestie, so nothing to list. moving on ✨

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and that's the whole page, no cap 🧚💖

this gorgeous little number comes to you from the MPI manual, page MPIX_Request_is_complete(3), dated 4/10/2026 — she's fresh, she's fabulous, she's complete 💅✨🌸