|R0||Address of error handler, or 0 to read|
|R1||Pointer to buffer for the error handler, or 0 to read|
|R2||Address of escape state change handler, or 0 to read|
|R3||Address of event handler, or 0 to read|
|R0||Previous error handler address|
|R1||Previous buffer address|
|R2||Previous escape routine address|
|R3||Previous event handler address|
The purpose of this call is to read or write address handlers.
This call is deprecated, and should not be used. OS_ChangeEnvironment should be used instead.