Difference between revisions of "ON ERROR"

Revision as of 07:04, 12 December 2012

Purpose

Trap program errors

Syntax

ON ERROR [<command>]

See Also

DOSERROR(), DISPLAY CALLS, ERRNO(), ERROR(), LIST CALLS, MESSAGE(), PROCLINE(), PROCNAME(), RETRY, SET ONERROR, STRERROR()

Description

The ON ERROR command causes the specified <command> to be executed if an error is encountered in a program. If ON ERROR is specified without a <command>, then the default Lianja behavior will be restored.

<command>

The <command> can be any Lianja command. After an error is encountered, the ERROR() function will return the error number, and the MESSAGE() function will return the error message. Specifying an '*' as the command causes any errors to be ignored, so should be used with caution.

Example

procedure badfile
  on error
  set message to "File does not exist."
return to master
 
on error do badfile
use patrons

[Category:Error Handling]]