MQTTSubscribe_options(3)

💖 MQTTSubscribe_options(3) 💖

okay bestie, so this is a page from the Library Functions Manual and it's all about MQTTSubscribe_options — literally the glow-up that MQTT V5 gave us. periodt. ✨

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✨ NAME ✨

MQTTSubscribe_options — the struct holding all your MQTT V5 subscribe options, no cap 🌸

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🦋 SYNOPSIS 🦋

#include <MQTTSubscribeOpts.h>

🎀 Data Fields 🎀

char struct_id [4]
int struct_version
unsigned char noLocal
unsigned char retainAsPublished
unsigned char retainHandling

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💅 Detailed Description 💅

ngl, this is just the MQTT V5 subscribe options — everything except QoS, because QoS was already a whole thing before V5 existed. she's the new girl on the block, and she ate. 👑

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🌈 Field Documentation 🌈

char struct_id[4]

the eyecatcher for this structure, iykyk. it Must be MQSO. like, no other option, bestie. it's the vibe check for your struct. 💀

int struct_version

the version number of this structure. it Must be 0. that's it. that's the whole field. iconic. ⭐

unsigned char noLocal

you want to NOT receive your own publications? set this to 1. 🫶

set it to 0 and you get the original MQTT behaviour — all messages matching the subscription are received, including your own lil messages coming home to roost. 🙈

unsigned char retainAsPublished

want to keep the retain flag exactly as it was on the original publish message? set to 1. 🎀

if you set 0, it defaults to the original MQTT behaviour, where the retain flag is only set on publications sent by a broker if in response to a subscribe request. lowkey a whole different vibe.

unsigned char retainHandling

okay so this one has three moods, and you gotta pick one:

1. 0 — send retained messages at the time of the subscribe (this is the original MQTT behaviour, the classic) ✨
2. 1 — send retained messages on subscribe only if the subscription is new 👀
3. 2 — do not send retained messages at all. simply no. not today. 💅

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bestie pls remember: struct_id must be MQSO and struct_version must be 0. these aren't suggestions, they're the rules, fr fr. 🔥

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💜 Author 💜

Generated automatically by Doxygen for the Paho MQTT C Client Library, straight from the source code. not a human, just a lil robot doing its thing. 🤖🌸

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mwah, that's the whole page bestie 🫶 — brought to you by the Paho MQTT C Client Library, dated Tue Jun 2 2026 00:00:00, and page number MQTTSubscribe_options(3) because we keep it cutesy and catalogued. bye now, go subscribe to something. 💖✨🎀