NNG_AIO(5)

💖 NNG_AIO 💖

okay bestie, welcome to the nng_aio page — that's the asynchronous I/O handle from the NNG Reference Manual, and yes it's giving main character energy ✨

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✨ SYNOPSIS ✨

#include <nng/nng.h>

typedef struct nng_aio nng_aio;

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🦋 DESCRIPTION 🦋

so. an nng_aio is an opaque structure — meaning you don't get to peek inside, bestie, it's mysterious on purpose 💅 — and it's used in conjunction with asynchronous I/O operations.

Every single asynchronous operation uses one of these structures. And here's the rule: each one can only be used with a single operation at a time. No sharing, no multitasking that one handle, one op at a time fr fr 🙈

Asynchronous operations are performed without blocking the calling application threads. That's the whole point, that's the slay. Instead, your app registers a callback function that gets executed when the operation is complete — whether it went great or it went terribly, doesn't matter, it still fires. And this callback will be executed exactly once. Not zero times, not two times. Once. periodt 🌈

The asynchronous I/O framework also supports cancellation of operations that are already in progress (see nng_aio_cancel()), and it lets you set a maximum timeout for them to complete within (see nng_aio_set_timeout()). So you can yeet an op if it's taking too long, iconic behavior honestly 💅

It is also possible to initiate an asynchronous operation, and then wait for it to complete using nng_aio_wait(). Sometimes you just wanna sit there and wait for your lil guy, and that's valid 🫶

These structures are created using nng_aio_alloc(), and destroyed using nng_aio_free(). Make them, use them, free them. The circle of life bestie 🧚

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🌸 SEE ALSO 🌸

• nng_aio_abort(3)
• nng_aio_alloc(3)
• nng_aio_cancel(3)
• nng_aio_count(3)
• nng_aio_free(3)
• nng_aio_get_input(3)
• nng_aio_get_msg(3)
• nng_aio_get_output(3)
• nng_aio_result(3)
• nng_aio_set_input(3)
• nng_aio_set_iov(3)
• nng_aio_set_msg(3)
• nng_aio_set_timeout(3)
• nng_aio_stop(3)
• nng_aio_wait(3)
• nng_strerror(3)
• nng_aio(5)
• nng(7)

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okay that's the whole page, you ate that 🍓 this was the NNG Reference Manual version, dated 2026-06-30, and we were literally just reading NNG_AIO(5). go forth and async responsibly, bestie 💖👑