| % File src/library/base/man/taskCallbackNames.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2016 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{taskCallbackNames} |
| \alias{getTaskCallbackNames} |
| \title{Query the Names of the Current Internal Top-Level Task Callbacks} |
| \description{ |
| This provides a way to get the names (or identifiers) |
| for the currently registered task callbacks |
| that are invoked at the conclusion of each top-level task. |
| These identifiers can be used to remove a callback. |
| } |
| \usage{ |
| getTaskCallbackNames() |
| } |
| \value{ |
| A character vector giving the name for each of the |
| registered callbacks which are invoked when |
| a top-level task is completed successfully. |
| Each name is the one used when registering |
| the callbacks and returned as the in the |
| call to \code{\link{addTaskCallback}}. |
| } |
| \note{ |
| One can use \code{\link{taskCallbackManager}} |
| to manage user-level task callbacks, |
| i.e., S-language functions, entirely within |
| the S language and access the names |
| more directly. |
| } |
| \seealso{ |
| \code{\link{addTaskCallback}}, |
| \code{\link{removeTaskCallback}}, |
| \code{\link{taskCallbackManager}}\\ |
| \url{https://developer.r-project.org/TaskHandlers.pdf} |
| } |
| \examples{ |
| n <- addTaskCallback(function(expr, value, ok, visible) { |
| cat("In handler\n") |
| return(TRUE) |
| }, name = "simpleHandler") |
| |
| getTaskCallbackNames() |
| |
| # now remove it by name |
| removeTaskCallback("simpleHandler") |
| |
| |
| h <- taskCallbackManager() |
| h$add(function(expr, value, ok, visible) { |
| cat("In handler\n") |
| return(TRUE) |
| }, name = "simpleHandler") |
| getTaskCallbackNames() |
| removeTaskCallback("R-taskCallbackManager") |
| } |
| \keyword{environment} |