MPI_T_CVAR_HANDLE_ALLOC(3)

💅 MPI_T_CVAR_HANDLE_ALLOC(3) ✨

okay so bestie, this is a page straight out of the Open MPI docs — and it's literally the MPI_T_cvar_handle_alloc / MPI_T_cvar_handle_free girlies. Control variable handles: you get one, you give it back. That's the whole vibe. 🎀

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🌸 NAME 🌸

MPI_T_cvar_handle_alloc, MPI_T_cvar_handle_free — the allocate/free duo for control variable handles 💖

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✨ SYNTAX ✨

🦋 C Syntax

#include <mpi.h>

int MPI_T_cvar_handle_alloc(int cvar_index, void *obj_handle,
                            MPI_T_cvar_handle *handle, int *count)

int MPI_T_cvar_handle_free(MPI_T_cvar_handle *handle)

like. look at those signatures. immaculate. no notes. 👑

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🌈 DESCRIPTION 🌈

okay so MPI_T_cvar_handle_alloc binds the control variable you picked in cvar_index to the MPI object you're pointing at with obj_handle. match made in heaven fr fr 🫶

and here's the thing — if MPI_T_cvar_get_info hands you back MPI_T_BIND_NO_OBJECT as that variable's binding, then the obj_handle argument is literally just ignored. it's giving background character. 💀

the number of values this control variable represents comes back to you in the count parameter. and lowkey if the control variable is a string? then count is the maximum length of the string. yes bestie, that's the length cap, not the actual length. iykyk ✨

then MPI_T_cvar_handle_free does the cleanup arc — it frees a handle that was allocated by MPI_T_cvar_handle_alloc and sets the handle argument to MPI_T_CVAR_HANDLE_NULL. main character exit, we love to see it 🚪💅

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🎀 NOTES 🎀

ngl, here's the tea: Open MPI does not currently support binding MPI objects to control variables — so the obj_handle argument is always ignored. always always. it's not you, it's the implementation 😭

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💀 ERRORS 💀

MPI_T_cvar_handle_alloc will fail if:

• MPI_T_ERR_NOT_INITIALIZED: the MPI Tools interface is not initialized 🙈
• MPI_T_ERR_INVALID_INDEX: the control variable index is invalid — bestie that index does not exist 🚫
• MPI_T_ERR_OUT_OF_HANDLES: no more handles available, we're all out, come back never 💀

MPI_T_cvar_handle_free will fail if:

• MPI_T_ERR_NOT_INITIALIZED: the MPI Tools interface is not initialized 🙈
• MPI_T_ERR_INVALID_HANDLE: the handle is invalid, that's not a real one queen 🎀

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🔥 SEE ALSO 🔥

• MPI_T_cvar_get_info

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👑 COPYRIGHT 👑

2003-2026, The Open MPI Community

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and that's the page, bestie! 🦋 this version is dated Sep 11, 2026 and it's the Open MPI MPI_T_CVAR_HANDLE_ALLOC(3) realness — go forth, allocate responsibly, free your handles, slay 💜✨🌸