MPI_T_CVAR_GET_NUM(3)

💅 NAME

MPI_T_cvar_get_num — bestie, this is the one that tells you how many control variables exist right now ✨

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🦋 SYNTAX

C Syntax

#include <mpi.h>

int MPI_T_cvar_get_num(int *num_cvar)

That's it. One include, one call, one pointer. Slay 🎀

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🌸 OUTPUT PARAMETERS

• num_cvar — the current number of control variables 💖 (this is where the answer lands, so pass it a real int *, mwah)

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✨ DESCRIPTION

Okay so here's the vibe: MPI_T_cvar_get_num queries the current number of control variables. That's the whole job and it does it flawlessly, no cap 👑

But here's the iconic little detail you need to internalize: the number of control variables may increase throughout the execution of the process — but it will never decrease. Never. Not once. So if you grabbed the count earlier and then grabbed it again and it's bigger? That's not a bug, that's just growth 🌱. It does not shrink, so don't build your whole life around the number going down, because it won't, periodt.

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🔥 ERRORS

MPI_T_cvar_get_num will fail if:

• MPI_T_ERR_NOT_INITIALIZED — the MPI Tools interface is not initialized 😭 (like, you gotta set up the tools interface first, bestie, it's giving "you skipped the prerequisite")

fr fr, if you see this error, the MPI Tools interface isn't initialized — that's the whole reason, go initialize it and come back 🫶

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👑 COPYRIGHT

2003-2026, The Open MPI Community

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That's the whole page, gorgeous — go count some control variables 💜

cute lil sign-off: this was the Open MPI manual, section 3 of the MPI_T_CVAR_GET_NUM era, dated Sep 11, 2026 🦋✨