MPI_T_CVAR_WRITE(3)

💖 MPI_T_CVAR_WRITE(3) 💖

okay bestie, welcome to the Open MPI corner of the manual. this one's called MPI_T_cvar_write — she writes the value of a bound control variable. yes, writes. she's the one doing the setting, not the getting. iconic behavior honestly ✨

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🌸 SYNTAX 🌸

C Syntax 🎀

#include <mpi.h>

int MPI_T_cvar_write(MPI_T_cvar_handle handle, const void *buf)

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🦋 INPUT PARAMETERS 🦋

• handle — the handle of the control variable you're about to write to. this is the lil ID card of the variable you want to touch 💅
• buf — initial address of the storage location for the variable value. like, the address where the value lives. she's just the pointer, no cap 🫶

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✨ DESCRIPTION ✨

so here's the tea: MPI_T_cvar_write sets the value of the control variable that's identified by the handle you passed in handle, and it takes that value from the buffer you gave it in buf. literally that's the whole job 🌈

and listen — the caller must ensure that the buffer specified in buf is large enough to hold the entire value of the control variable. not "kinda big enough". the ENTIRE value. do not skimp, do not guess, do not manifest a bigger buffer into existence 😭

also, if the variable has global scope, then any write call has to be issued on all connected MPI processes. all of them. every single one. it's giving group project where everyone actually has to show up 💀

for more info, go read MPI-3 section 14.3.6. iykyk 📖

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💅 ERRORS 💅

MPI_T_cvar_write will fail if any of these pop up:

• MPI_T_ERR_NOT_INITIALIZED — the MPI Tools interface isn't initialized. she's not awake yet bestie, you gotta wake her up first 🙈
• MPI_T_ERR_INVALID_HANDLE — the handle is invalid. fake ID, we can't let her in 😭
• MPI_T_ERR_CVAR_SET_NOT_NOW — the variable cannot be set at this moment. not now, not the vibe, try again later ⏳
• MPI_T_ERR_CVAR_SET_NEVER — the variable cannot be set until end of execution. and by "until end of execution" we mean the set is never happening before then. never. periodt 💀

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👑 SEE ALSO 👑

• MPI_T_cvar_handle_alloc
• MPI_T_cvar_get_info

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🍓 COPYRIGHT 🍓

2003-2026, The Open MPI Community

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and that's the whole page babes, ty for reading 💜 this was Open MPI, MPI_T_CVAR_WRITE(3), dated Sep 10, 2026. mwah, go write some control variables responsibly 🎀✨💖