This documentation is for the TIP (development tree) of NNG and may represent unreleased changes or functionality that is experimental, and is subject to change before release. The latest released version is v1.3.2. See the documentation for v1.3.2 for the most up-to-date information.

nng_ctx_recv(3)

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.

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.

The semantics of what receiving a message means varies from protocol to protocol, so examination of the protocol documentation is encouraged.

RETURN VALUES

None. (The operation completes asynchronously.)

ERRORS

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.

SEE ALSO