Errors

Syntax#

error [text] [number integer]

Parameters#

Parameter	Details
unnamed	A textual description of the error.
number	The error’s number, an integer (usually negative).
## Catching errors
Error handling in AppleScript uses `try` `on error`. The code which may throw an error goes in the `try` block and any error handling code is in the `on error` block. The `on error` block is closed using `end try`.

foo is not defined, so throws an error. When an error occurs, the dialog is displayed.

try
    foo
on error
    display dialog "An error occurred"
end try

It is possible to obtain the error message and error number using on error errormsg number errorno where errormsg and errorno are variable names for the error message and error number.

try
    foo
on error errormsg number errorno
    display dialog errormsg & errorno
end try

The variable foo is not defined.-2753

Throwing errors

You can throw your own errors using error. Execution stops at uncaught errors. By default, the error message is “An error has occurred.” with error number -2700.

error

error “An error has occurred.” number -2700 from «script» to item

You can pass a message with the error which overrides the default message.

error "testing errors"

error “testing errors” number -2700 from «script» to item

Error numbers can also be passed using the parameter number:

error "testing errors" number -1

error “testing errors” number -1 from «script» to item

If you include an error number but no error message, an error message is written for you.

error number -1

error “An error of type -1 has occurred.” number -1 from «script» to item

Some error numbers are reserved for certain types of error.

error number -42

error “Too many files open” number -42 from «script» to item