handleError {RGtk2} | R Documentation

## Error handling

### Description

The `handleError` function is an internal utility for use by packages extending RGtk2. It decides how to handle an error emitted by GTK+ or one of the other libraries.

### Usage

    handleError(x, .errwarn)

### Arguments

`x` | The result of a call to an underlying library.
`.errwarn` | DEPRECATED. Whether to emit a warning if there is an error and `getOption("RGtk2::newErrorHandling")` is `FALSE` (`TRUE` is now the default).

### Details

There are currently two modes of error handling in RGtk2. One was introduced with RGtk2 2.20.0. It is now the default and will eventually replace the older one. Setting the option `RGtk2::newErrorHandling` to `FALSE` disables the newer error handling, to ease the transition of code.

The original behavior is to return a list from every library function that might raise an error. The `error` component of the list holds the error, while the primary return value of the underlying function is named `retval` (and there might be additional return values). If there is no error, the `error` component is `NULL`. Otherwise, it holds an object of type `simpleError` (actually until 2.20.0 this was just a list with a very similar structure).

The new approach, active when `getOption("RGtk2::newErrorHandling")` returns `TRUE`, will throw any error (as a `simpleError` object). An error in the underlying library is an error in R. No error object is returned. This often results in a simpler return value, as a list is no longer necessary unless there are multiple return values from the wrapped function. The `.errwarn` argument is ignored and will soon be removed from the wrappers along with the old error handling, resulting in a simpler API.

### Value

`x`, with the error removed if the "RGtk2::newErrorHandling" option is `TRUE`.

### Author(s)

Michael Lawrence

[Package RGtk2 version 2.20.40 Index]