This documentation is for version v1.3.0 of NNG, but the latest released version is v1.8.0. see the documentation for v1.8.0 for the most up-to-date information.


#include <nng/nng.h>

typedef struct nng_aio nng_aio;


An nng_aio is an opaque structure used in conjunction with asynchronous I/O operations. Every asynchronous operation uses one of these structures, each of which can only be used with a single operation at a time.

Asynchronous operations are performed without blocking calling application threads. Instead the application registers a “callback” function to be executed when the operation is complete (whether successfully or not). This callback will be executed exactly once.

The asynchronous I/O framework in nng also supports cancellation of operations that are already in progress (see nng_aio_cancel()), as well setting a maximum timeout for them to complete within (see nng_aio_set_timeout()).

It is also possible to initiate an asynchronous operation, and wait for it to complete using nng_aio_wait().

These structures are created using the nng_aio_alloc(), and destroyed using nng_aio_free().