MPI_T_ENUM_GET_INFO(3)

💖 MPI_T_ENUM_GET_INFO — bestie, let's go query an enumerator 💖

okay so real quick: this is a page from the Open MPI manual, section 3 (the library-calls girlies ✨). It's called MPI_T_enum_get_info, and it does exactly one thing but it does it well: it tells you stuff about an enumerator. Cute, right? Let's get into it. 🎀

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✨ NAME ✨

MPI_T_enum_get_info — query information about an enumerator 🔍

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✨ SYNTAX ✨

C Syntax 🌸

#include <mpi.h>

int MPI_T_enum_get_info(MPI_T_enum enumtype, int *num, char *name, int *name_len)

that's it, that's the whole signature, no cap 🫶

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✨ INPUT PARAMETERS ✨

• enumtype — the enumerator you want the tea on. 🍓

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✨ INPUT/OUTPUT PARAMETERS ✨

• name_len — it's giving both directions, bestie. On the way in it's the length of the string and/or the buffer for name; on the way out it comes back changed (more on that in NOTES, keep reading 👀).

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✨ OUTPUT PARAMETERS ✨

• num — how many discrete values this enumeration represents. the count. the number. the vibe check result. 🔢
• name — a buffer where the string containing the name of the category gets dropped off. 🧺

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✨ DESCRIPTION ✨

So MPI_T_enum_get_info can be used to query information about an enumerator, periodt 💅 And specifically, the function returns the number of discrete values represented by this enumerator in the num parameter. That's the main event. That's the moment.

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🌈 NOTES 🌈

Okay this part is important so listen up bestie, because the string handling is a whole thing 🫠

This MPI tool interface function returns the name of the enumeration as a string. It takes two arguments for the string, not one:

• name — which specifies a buffer where the name of the should be stored 👑 (yes, the original says "the name of the" and we are respecting the original, it's iconic in its own way)
• name_len — which must initially specify the size of the buffer pointed to by name.

Then here's the little dance it does ✨: this function will copy at most name_len - 1 characters of the name, and it sets name_len to the number of characters returned + 1. So name_len comes back different from how you sent it. Character development, literally. 🦋

And if name_len is NULL, or the value specified in name_len is 0, then the name buffer is ignored and the name of the enumeration is not returned at all. so don't be shocked when your name is empty, that's the deal you signed up for 😭

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💀 ERRORS 💀

MPI_T_enum_get_info will fail if:

• MPI_T_ERR_NOT_INITIALIZED — the MPI Tools interface not initialized. you gotta set her up first, she's not gonna just appear. 🙈
• MPI_T_ERR_INVALID_INDEX — the enumeration is invalid or has been deleted. it's gone, babe, it's not coming back 💔

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👑 Copyright 👑

2003-2026, The Open MPI Community

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and that's the whole page, bestie!! 🎀 This was the MPI_T_ENUM_GET_INFO(3) page from Open MPI, and it was last touched Sep 10, 2026 — which honestly, shoutout to the Open MPI Community for keeping it fresh since 2003, that's longevity, that's main character energy fr fr 💖✨🦋 Slay, go query your enumerators responsibly. 🫶💅