nanonext (version 0.10.4)

send_aio: Send Async

Description

Send data asynchronously over a connection (Socket, Context or Stream).

Usage

send_aio(con, data, mode = c("serial", "raw", "next"), timeout = NULL)

Value

A 'sendAio' (object of class 'sendAio') (invisibly).

Arguments

con

a Socket, Context or Stream.

data

an object (a vector, if mode = 'raw').

mode

[default 'serial'] one of 'serial' to send serialised R objects, 'raw' to send atomic vectors of any type as a raw byte vector, or 'next' (see 'Send Modes' section below). Alternatively, specify an integer position in the vector of choices e.g. 1L for 'serial' or 2L for 'raw' etc. For Streams, 'raw' is the only option and this argument is ignored.

timeout

[default NULL] integer value in milliseconds or NULL, which applies a socket-specific default, usually the same as no timeout.

Send Modes

The default mode 'serial' sends serialised R objects to ensure perfect reproducibility within R. When receiving, the corresponding mode 'serial' should be used.

Mode 'raw' sends atomic vectors of any type as a raw byte vector, and must be used when interfacing with external applications or raw system sockets, where R serialization is not in use. When receiving, the mode corresponding to the vector sent should be used.

Mode 'next' sends serialised R objects, with native extensions enabled by nextmode. This allows 'refhook' functions to be registered for custom serialization and unserialization of reference objects, such as those accessed via an external pointer. When receiving, mode 'serial' should be used as 'next' sends are fully compatible.

Details

Async send is always non-blocking and returns a 'sendAio' immediately.

For a 'sendAio', the send result is available at $result. An 'unresolved' logical NA is returned if the async operation is yet to complete. The resolved value will be zero on success, or else an integer error code.

To wait for and check the result of the send operation, use call_aio on the returned 'sendAio' object.

Alternatively, to stop the async operation, use stop_aio.

Examples

pub <- socket("pub", dial = "inproc://nanonext")

res <- send_aio(pub, data.frame(a = 1, b = 2), timeout = 100)
res
res$result

res <- send_aio(pub, "example message", mode = "raw", timeout = 100)
call_aio(res)$result

close(pub)