# nng_aio_wait ## NAME nng_aio_wait --- wait for asynchronous I/O operation ## SYNOPSIS ```c #include void nng_aio_wait(nng_aio *aio); ``` ## DESCRIPTION The `nng_aio_wait()` function waits for an asynchronous I/O operation to complete. If the operation has not been started, or has already completed, then it returns immediately. If a callback was set with _aio_ when it was allocated, then this function will not be called until the callback has completed. > [!IMPORTANT] > This function should never be called from a function that itself > is a callback of an [`nng_aio`][aio], either this one or any other. > Doing so may result in a deadlock. ## SEE ALSO [nng_aio_abort][nng_aio_abort], [nng_aio_busy][nng_aio_busy] {{#include ../refs.md}}