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>

size_t nng_aio_count(nng_aio *aio);


The nng_aio_count() returns the number of bytes transferred by the asynchronous operation associated with the handle aio.

Some asynchronous operations do not provide meaningful data for this function; for example operations that establish connections do not transfer user data (they may transfer protocol data though) — in this case this function will generally return zero.

This function is most useful when used with operations that make use of of a scatter/gather vector (set by nng_aio_set_iov()).

The return value from this function is undefined if the operation has not completed yet. Either call this from the handle’s completion callback, or after waiting for the operation to complete with nng_aio_wait().


The number of bytes transferred by the operation.