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 addTaskCallback .

Note

One can use taskCallbackManager to manage user-level task callbacks, i.e., S-language functions, entirely within the S language and access the names more directly.

See Also

addTaskCallback , removeTaskCallback , taskCallbackManager \ 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")