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.

    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.

    Note

    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

nng_aio_get_msg(3), nng_aio_set_msg(3), nng_msg_alloc(3), nng_strerror(3), nng_aio(5), nng_ctx(5), nng_msg(5), nng(7)