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How the FWErrorsys() function works ?

FWH procedure FWErrorSys() is identical to FWH procedure ErrorSys() that it is automatically called by Harbour.

procedure ErrorSys() invokes function ErrorBlock() to replace the default application errorBlock:

ErrorBlock( { | e | ErrorDialog( e ) } )

I wrote the FW Error Sys() function in which I specified my code block

Error Block( { | e | MyFunc(), Error Dialog( e ) } )
However, when compiling, I get an error - the Error Dialog() function was not found

function ErrorDialog( e ) is static so you have to modify errsysw.prg to make it public or entirely replace FWH errsysw.prg with one of your own

You wrote:

Code: Select all  Expand view

Error Block( { | e | MyFunc(), Error Dialog( e ) } )

From this, I understand that when an error occurs, you want MyFunc() should be executed first and then invoke the FWH ErrorDialog.

We can achieve this without modifying errsysw.prg
Please try this sample:

Code: Select all  Expand view

#include "fivewin.ch"

function Main()

   local bFwErr

   bFwErr   := ErrorBlock()
   ErrorBlock( { |e| MyFunc( e ), Eval( bFWErr, e ) } )

   ? "Will now generate Error and see"
   ? Date() == 9

return nil

function MyFunc( e )

   MsgInfo( e:Description + CRLF + e:Operation, "MY FUNC" )
   ? "Next, you will see FWH Error Dialog"

return nil

Please just run the sample and see how your MyFunc() is exeucted first and later FWH's ErrorDialog() is executed.

In case, we want to take some action after the FWH's ErrorDialog() is executed, we can do like this:

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#include "fivewin.ch"

function Main()

   SetPostErrorAction( { |cLogFile, e| MyFunc( cLogFile, e ) } )

   ? "Will now generate Error and see"
   ? Date() == 9

return nil

function MyFunc( cLogFile, e )

   ? "Sending email " + TrueName( cLogFile )

return nil

In case we do not like FWH provided ErrorDialog and like to display our own ErrorDialog, we can do this:

Code: Select all  Expand view

#include "fivewin.ch"

function Main()

   SetErrorDialog( { |e, aStack, cErrLogText, cErrLogFile | ;
       MyErrorDialog( e, aStack, cErrLogText, cErrLogFile ) } )

   ? "Will now generate Error and see"
   ? Date() == 9

return nil

function MyErrorDialog( e, aStack, cErrLogText, cErrLogFile )

   MsgInfo( e:Description + CRLF + e:Operation + CRLF + ;
      FW_ArrayAsList( e:Args, ", " ) + CRLF + ;
      FW_ArrayAsList( aStack, CRLF ), ;
      "MY ERROR DIALOG" )

return nil

Please run the above three programs as it is and see.
We can do all the aboe without modifying the errsysw.prg

Lastly,
If we do not like to use FWH's error handling and like to have our own error handler

Then at the beginning of the application, execute

Code: Select all  Expand view

ErrorBlock( { |e| MyErrorHandler( e ) } )

and have our own error handling module like "errsysmy.prg" with this function.

From this, I understand that when an error occurs, you want MyFunc() should be executed first and then invoke the FWH ErrorDialog.

Yes, that's exactly what I wanted. Thank you, Rao !