nng_ctx_recv
NAME
nng_ctx_recv — receive message using context asynchronously
SYNOPSIS
#include <nng/nng.h>
void nng_ctx_recv(nng_ctx ctx, nng_aio *aio);
DESCRIPTION
The nng_ctx_recv() receives a message using the
context s asynchronously.
When a message is successfully received by the context, it is
stored in the aio by an internal call equivalent to
nng_aio_set_msg(), then the completion
callback on the aio is executed.
In this case, nng_aio_result() will
return zero.
The callback function is responsible for retrieving the message
and disposing of it appropriately.
important
Failing to accept and dispose of messages in this case can lead to memory leaks.
If for some reason the asynchronous receive cannot be completed
successfully (including by being canceled or timing out), then
the callback will still be executed,
but nng_aio_result() will be non-zero.
tip
The semantics of what receiving a message means varies from protocol to protocol, so examination of the protocol documentation is encouraged.
ERRORS
The following errors may be set on the aio, if the operation fails.
NNG_ECANCELED: The operation was aborted.NNG_ECLOSED: The context ctx is not open.NNG_ENOMEM: Insufficient memory is available.NNG_ENOTSUP: The protocol for context ctx does not support receiving.NNG_ESTATE: The context ctx cannot receive data in this state.NNG_ETIMEDOUT: The receive timeout expired.