MPI_T_PVAR_READRESET(3)

💅 MPI_T_pvar_readreset — the Open MPI glow-up 🦋

okay bestie, so we're in the Open MPI manual and today's main character is MPI_T_pvar_readreset — the function that reads a performance variable and resets it, all in one atomic lil swoop. no cap, it's giving "one trip, two jobs" energy ✨

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✨ SYNOPSIS ✨

🎀 C Syntax

#include <mpi.h>

int MPI_T_pvar_readreset(MPI_T_pvar_session session, MPI_T_pvar_handle handle, const void *buf)

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🌸 INPUT PARAMETERS 🌸

• session — the performance experiment session. like, the whole vibe container for your experiment 🧚
• handle — the performance variable handle. this is your little VIP pass to one specific variable 💅
• buf — the initial address of the storage location for the variable value. you're handing it a place to put the answer 🎀

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💖 DESCRIPTION 💖

so MPI_T_pvar_readreset does the cutest thing: it atomically queries and resets the value of a performance variable that's bound to the handle you passed in handle, inside the session you passed in session. the result gets stashed in the buffer that buf points to. 💫

but listen — this function can only be used with performance variables that are atomic and not readonly. if your variable isn't both of those, it's a no from the function, periodt 🙈

and one thing you cannot skip: the caller has to make sure the buffer pointed to by buf is big enough to hold the entire value of the performance variable. under-size it and that's on you, bestie 😭 like, the function is not gonna check your math.

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💀 ERRORS 💀

MPI_T_pvar_readreset will fail if:

• MPI_T_ERR_NOT_INITIALIZED — the MPI Tools interface not initialized 🫠
• MPI_T_ERR_INVALID_HANDLE — the handle is invalid or not associated with the session 🙅
• MPI_T_ERR_INVALID_SESSION — the session argument is not a valid session 💀
• MPI_T_ERR_PVAR_NO_ATOMIC — the variable cannot be read and written atomically 🚫
• MPI_T_ERR_PVAR_NO_WRITE — the variable cannot be reset 🚫

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👑 SEE ALSO 👑

like obviously go read these too, iykyk:

• MPI_T_pvar_handle_alloc
• MPI_T_pvar_get_info
• MPI_T_pvar_session_create
• MPI_T_pvar_read
• MPI_T_pvar_reset

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🌈 COPYRIGHT 🌈

2003-2026, The Open MPI Community — iconic, they've been serving since 2003 🔥

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okay that's the whole page, bestie, you ate that 🫶 and for the sign-off: this was the Open MPI manual, page MPI_T_PVAR_READRESET(3), dated Sep 11, 2026 — go forth and readreset responsibly 💜🦋⭐