taskCallbackNames {base}

R Documentation

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\ http://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")

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