NNG_LISTENER(5)

💖 NNG_LISTENER(5) 💖

okay so bestie, welcome to the nng_listener page from the NNG Reference Manual ✨ grab a snack, this one's short but it's lowkey foundational 🫶

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✨ NAME ✨

nng_listener — listener 👑 (yes that's the whole name, she's simple and she's iconic)

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🌸 SYNOPSIS 🌸

#include <nng/nng.h>

typedef struct nng_listener_s nng_listener;

that's it. that's the whole thing. a typedef and a dream 💅

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🦋 DESCRIPTION 🦋

so an nng_listener is a handle to a listener object, and its whole job — her entire purpose, her main character arc — is creating nng_pipe objects by accepting incoming connections. 🌈

and like, not just one pipe. one single listener object can spin up many pipes at the same time, no cap. think of it like an HTTP server that's got a whole crowd of connections to a bunch of different clients all at once. she's popular, she's booked, she's thriving 💖

listener objects get created by nng_listener_create() or nng_listen(), and they're always associated with a single nng_socket. one socket, one listener-buddy (well, per listener anyway, iykyk).

⚠️ Important — the nng_listener structure is always passed by value, both for input parameters and return values, and you should treat it as opaque. passing structs around like this is actually a glow-up because it gives the compiler a chance to do accurate type checks in functions that pass values of this type. so like, don't go poking at her insides, let the compiler do the vibes check 🔥

💡 Tip — a given nng_socket can have multiple listener objects, multiple dialer objects, or even some of both. mix and match, she contains multitudes ✨

💡 Tip — the client/server relationship that dialer/listener describes is completely orthogonal to any similar relationship in the protocols. like fr fr, a rep socket may use a dialer to connect to a listener on an req socket. this orthogonality is genuinely a slay because it can lead to innovative solutions to otherwise challenging communications problems. not me being obsessed with this design 😭

listener objects may be destroyed by the nng_listener_close() function. they also get closed when their associated socket is closed — they're ride or die like that 🥺

🎀 Initialization 🎀

a listener may be initialized using the macro NNG_LISTENER_INITIALIZER before it is opened, so you don't confuse it with a valid open listener. do this. seriously. it's the self-care step 💅

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👑 SEE ALSO 👑

• nng_listen(3)
• nng_listener_close(3)
• nng_listener_create(3)
• nng_listener_getopt(3)
• nng_listener_id(3)
• nng_listener_setopt(3)
• nng_listener_start(3)
• nng_dialer(5)
• nng_pipe(5)
• nng_socket(5)
• nng(7)

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okay that's the whole page bestie, you ate it, go forth and accept some connections 🫶✨

this was the NNG Reference Manual version dated 2026-06-30, page NNG_LISTENER(5) — k byeeee 💜🧚🍓