MPI_Status_get_error(3)

💖 MPI_Status_get_error(3) — the MPI bestie manual 💖

okay so we're in the MPI manual section, bestie, and today's main character is MPI_Status_get_error — she's the one who fishes your error code out of a status object. tiny function, huge slay. no cap. ✨

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✨ NAME ✨

MPI_Status_get_error — Get MPI_ERROR field from the status 🎀

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🌸 SYNOPSIS 🌸

int MPI_Status_get_error(const MPI_Status *status, int *error)

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🦋 INPUT PARAMETERS 🦋

• status — the status you're pulling the source rank out of (type: Status) 💅

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💜 OUTPUT PARAMETERS 💜

• error — the error that's chillin' in the MPI_ERROR field (integer) ✨

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🔥 THREAD AND INTERRUPT SAFETY 🔥

okay so this routine is thread-safe, which is iconic of her. that means multiple threads can all call her at the same time and nobody needs to bring their own thread locks — she's got it handled, periodt. 🫶

but — and this is the important part, don't skip it — she is not interrupt safe. typically that's because of memory allocation routines like malloc, or other non-MPICH runtime routines that aren't interrupt-safe themselves. so like, the interrupt vibe check? failed. 😭

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🌈 NOTES FOR FORTRAN 🌈

every MPI routine in Fortran (except MPI_WTIME and MPI_WTICK) gets an extra argument called ierr tacked on at 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. and in Fortran, MPI routines are subroutines, invoked with the call statement. 🧚

also, all MPI objects (like MPI_Datatype, MPI_Comm) are of type INTEGER in Fortran. 💖

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💀 ERRORS 💀

every MPI routine (except MPI_Wtime and MPI_Wtick) returns an error value — C routines as the return value of the function, Fortran routines in that last argument. before the value comes back to you, the current MPI error handler gets called. by default, this error handler aborts the MPI job — like, whole thing, gone. 😭

the error handler can be swapped out with MPI_Comm_set_errhandler (for communicators), MPI_File_set_errhandler (for files), and MPI_Win_set_errhandler (for RMA windows). the MPI-1 routine MPI_Errhandler_set may still be used but its use is deprecated — she's retired, let her rest. the predefined error handler MPI_ERRORS_RETURN may be used to make error values get returned instead. note that MPI does not guarantee an MPI program can continue past an error; however, MPI implementations will attempt to continue whenever possible. 🙈

• MPI_SUCCESS
  • no error; the MPI routine completed successfully. she 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 just go ask MPI_Error_string what's up, she always knows. 💅

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that's it, that's the whole page, you understood it, i'm so proud of you 🥹💖 this one came from the MPI manual, dated 4/10/2026, page MPI_Status_get_error(3) — go forth and retrieve those error fields, bestie, you're literally the main character of this MPI job. 🎀🦋⭐