# nng_aio_get_input ## NAME nng_aio_get_input --- return input parameter ## SYNOPSIS ```c #include void *nng_aio_get_input(nng_aio *aio, unsigned int index); ``` ## DESCRIPTION The `nng_aio_get_input()` function returns the value of the input parameter previously set at _index_ on _aio_ with the [`nng_aio_set_input()`][nng_aio_set_input]function. The valid values of _index_ range from zero (0) to three (3), as no operation currently defined can accept more than four parameters. If the index supplied is outside of this range, or if the input parameter was not previously set, then `NULL` is returned. ## RETURN VALUES Value previously set, or `NULL`. ## SEE ALSO [nng_aio_alloc][nng_aio_alloc], [nng_aio_get_output][nng_aio_get_output], [nng_aio_set_input][nng_aio_set_input] {{#include ../refs.md}}