ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Handling errors
Class name Description Notes
EOFError An EOFError exception is thrown when you
attempt to read past the end of the available data.
IllegalOperationError An IllegalOperationError exception is thrown
when a method is not implemented or the
implementation doesn't cover the current usage.
IOError An IOError exception is thrown when some type of
I/O exception occurs.
MemoryError A MemoryError exception is thrown when a
memory allocation request fails.
ScriptTimeoutError A ScriptTimeoutError exception is thrown when a
script timeout interval of 15 seconds is reached. By
catching a ScriptTimeoutError exception, you can
handle the script timeout more gracefully. If there
is no exception handler, the uncaught exception
handler displays a dialog box with an error
message.
StackOverflowError The StackOverflowError exception is thrown when
the stack available to the script has been
exhausted.
Last updated 6/6/2012
For example, an EOFError is thrown when one of the
read methods in the IDataInput interface is called and
there is insufficient data to satisfy the read request.
Examples of illegal operation error exceptions include
the following:
A base class, such as DisplayObjectContainer,
provides more functionality than the Stage can
support. For example, if you attempt to get or set a
mask on the Stage (using stage.mask), the Flash
runtime throws an IllegalOperationError with the
message “The Stage class does not implement this
property or method.”
A subclass inherits a method it does not require and
does not want to support.
Certain accessibility methods are called when Flash
Player is compiled without accessibility support.
Authoring-only features are called from a run-time
version of Flash Player.
You attempt to set the name of an object placed on
the timeline.
You get this error, for example, when a read-write
operation is attempted on a socket that is not
connected or that has become disconnected.
By default, ActionScript Virtual Machine 2 does not
impose a limit on how much memory an ActionScript
program allocates. On a desktop system, memory
allocation failures are infrequent. You see an error
thrown when the system is unable to allocate the
memory required for an operation. So, on a desktop
system, this exception is rare unless an allocation
request is extremely large; for example, a request for 3
billion bytes is impossible because a 32-bit Microsoft®
Windows® program can access only 2 GB of address
space.
To prevent a malicious developer from catching the
exception and staying in an infinite loop, only the first
ScriptTimeoutError exception thrown in the course of
a particular script can be caught. A subsequent
ScriptTimeoutError exception cannot be caught by
your code and immediately goes to the uncaught
exception handler.
A StackOverflowError exception might indicate that
infinite recursion has occurred.
69