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en:onerror [2016/08/13 12:36]
admin 		en:onerror [2016/08/15 04:40]
admin
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 ==== Format ==== ==== Format ====
-**onerror** [[labelprogamsyntax|label]]+**onerror** [[labelprogramsyntax|label]]
  
 ==== Description ==== ==== Description ====
-Causes the [[GosubReturn|Gosub]] at [[labelprogamsyntax|label]] to be executed when a runtime error occurs.  Program control may be resumed at the next statement with a [[GosubReturn|Return]] statement in the subroutine.  Error traps are kept in a stack so that the last defined trap, that has not been removed with an [[offerror|OffError]] will be the active one.+Causes the [[GosubReturn|Gosub]] at [[labelprogramsyntax|label]] to be executed when a runtime error occurs.  Program control may be resumed at the next statement with a [[GosubReturn|Return]] statement in the subroutine.  Error traps are kept in a stack so that the last defined trap, that has not been removed with an [[offerror|OffError]] will be the active one.
  
 You may not execute an OnError statement inside a [[Try|Try / Catch / End Try]] statement. You may not execute an OnError statement inside a [[Try|Try / Catch / End Try]] statement.
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 ==== Example ==== ==== Example ====
  
-See example of usage on [[Errorcodes|Error Codes]] and [[ThrowError|ThrowError]] pages.+<code> 
 +# test error trapping 
 +onerror nicetrap 
 +print 1 
 +next haha 
 +print 2 
 +open 999, "bogus.file" 
 +print "Runs Anyway" 
 + 
 +# test error trapping off and fail at any error (default) 
 +offerror 
 +print 3 
 +next hoho 
 +print "never get here" 
 + 
 +end 
 + 
 +nicetrap: 
 +# this is the nice error handler 
 +print "trap and run - error on line " + lasterrorline + " - error number " + lasterror + " message " + lasterrormessage + " (" + lasterrorextra + ")" 
 +return 
 +</code> 
 +will display\\ 
 +<code> 
 +1 
 +trap and run - error on line 4 - error number 4 message Next without FOR () 
 +2 
 +trap and run - error on line 6 - error number 5 message Invalid File Number () 
 +Runs Anyway 
 +3 
 +ERROR on line 12: Next without FOR  
 +</code> 
 + 
 +See additional example of usage on [[ThrowError|ThrowError]] page.
  
 ==== See Also ==== ==== See Also ====
en/onerror.txt · Last modified: 2020/02/28 10:46 (external edit)

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