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Description Usage Arguments Details Value Examples

View source: R/hold.R

The hold() function is a helper to turn a promises::promise() in a synchronous value: the R session awaits the fulfillment of the promise and returns the value of the fulfilled promise. An error is thrown if the promise is rejected or a timeout expires. This is a wrapper around later::run_now().

hold(
  x,
  timeout = 30,
  msg = paste("The asynchronous job has not finished in the delay of", timeout,
    "seconds.")
)

`x`	A `promises::promise()` object.
`timeout`	Number scalar, timeout in seconds. An error is thrown if the promise is still pending when the delay expires.
`msg`	Error message when the timeout expires.

This function must not be used inside a function that returns a promise. Otherwise, this will lead to an infinite loop.

The value of the promise once resolved.

## Not run: 

library(promises)
library(later)

pr <- promise(~ later(~ resolve("result of the async task"), 1))
value <- hold(pr)
cat(value, "\n")

## End(Not run)