call_aio retrieves the value of an asynchronous Aio operation, waiting
for the operation to complete if still in progress. For a list of Aios,
waits for all asynchronous operations to complete before returning.
call_aio_ is a variant that allows user interrupts, suitable for
interactive use.
Details
For a ‘recvAio’, the received value may be retrieved at
$data.
For a ‘sendAio’, the send result may be retrieved at
$result. This will be zero on success, or else an integer error
code.
To access the values directly, use for example on a ‘recvAio’
x: call_aio(x)$data.
For a ‘recvAio’, if an error occurred in unserialization or conversion of the message data to the specified mode, a raw vector will be returned instead to allow recovery (accompanied by a warning).
Note: this function operates silently and does not error even if ‘aio’ is not an active Aio or list of Aios, always returning invisibly the passed object.
Alternatively
Aio values may be accessed directly at $result for a
‘sendAio’, and $data for a ‘recvAio’. If the Aio
operation is yet to complete, an ‘unresolved’ logical NA will be
returned. Once complete, the resolved value will be returned instead.
unresolved may also be used, which returns TRUE only if an
Aio or Aio value has yet to resolve and FALSE otherwise. This is suitable
for use in control flow statements such as while or if.
Examples
s1 <- socket("pair", listen = "inproc://nanonext")
s2 <- socket("pair", dial = "inproc://nanonext")
res <- send_aio(s1, data.frame(a = 1, b = 2), timeout = 100)
res
#> < sendAio | $result >
call_aio(res)
res$result
#> [1] 0
msg <- recv_aio(s2, timeout = 100)
msg
#> < recvAio | $data >
call_aio_(msg)$data
#> a b
#> 1 1 2
close(s1)
close(s2)