How can I catch this Error or check to nil?
lazarus / 62-General

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SunyD · 2017-03-15 21:31

Hello,
i have following code from 3rd part:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i {$MODE
DELPHI } // <--- it is compiled with Delphi-Mode // PDataSetRecInfo
ist Pointer to Record TDataSetRecInfo// aBuffer is PChar//
dsRecInfoOfs is Integer; //..        with PDataSetRecInfo(aBuffer +
dsRecInfoOfs)^ do begin          riBookmarkFlag := bfCurrent;        
             //sometimes error here          riRecNo := 0;       
end;//.. 
Sometimes the programm crashs with Errorcode:
<TDataSetRecInfo>= cannot access memory at adress 0x58

It tried without success:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i {$MODE
DELPHI } // <--- it is compiled with Delphi-Mode     if
PDataSetRecInfo(aBuffer + dsRecInfoOfs)<>nil then //don't helps, it
passes every time        with PDataSetRecInfo(aBuffer + dsRecInfoOfs)^
do begin          riBookmarkFlag := bfCurrent;                      
//sometimes error here          riRecNo := 0;        end; 
Does anyone know how can I catch this Error or check to nil?

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ASerge · 2017-03-15 21:44

Quote from: Soner A. on March 15, 2017, 10:31:49 pm...or check to nil?
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i if aBuffer
<> nil then

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SunyD · 2017-03-15 21:55

Thanks, so easy I didn't see it

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Ñuño_Martínez · 2017-03-17 18:43

Just to clarify:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i      if
PDataSetRecInfo(aBuffer + dsRecInfoOfs)<>nil then //don't helps, it
passes every timeThis doesn't help because NIL is a pointer to address
x00000000, so NIL + anything <> NIL is TRUE in all cases.

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Kays · 2017-03-19 00:17

Quote from: ASerge on March 15, 2017, 10:44:50 pmCode: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i if aBuffer
<> nil thenI like my code more descriptive:Code: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i if
assigned(aBuffer) thenhttp://www.freepascal.org/docs-
html/rtl/system/assigned.html