What is ‘Access Violation at address Delphi error’ in Windows 10?
In this article, we are going to discuss on How to fix Access Violation at address error, Access Violation at address Delphi error in Windows 10/8/7. You will be guided with easy steps/methods to resolve the issue. Let’s starts the discussion.
‘Delphi’: Delphi is software that uses Delphi Dialect of Object Pascal Programming Language and provides an integrated development environment (IDE) for rapid application development of desktop, mobile, web and console software, currently developed and maintained by Embarcadero Technologies. Delphi’s complier generate native code for Microsoft Windows, MacOS, iOS, Android and Linux OS based devices.
However several Delphi users reported that they faced ‘Access Violation at address Delphi error’ when write the program and test it and then send it everywhere. This error indicates when you use Delphi in any software development when program fails to send the tested program. You might consider compiling your program with compilation instruction {$ D} – Delphi can create an image file that helps locate the source code for Access Violation errors.
The Project Options Dialog offers you to specify everything you need. For unit file, the debug information is recorded in unit file together with object code of unit. Access Violation at address error is usually appeared in the middle of your work on Delphi and caused you to postpone solving problem. Now, you will know how to easily find and exact path, source doe file, and line where the Access Violation at address error occurs if only conflicting address is given like ‘Search-Find Error…’. Access Violation at address Delphi error is appeared with following or similar way.
“Access violation at address <hex value> in module <application name> Read of address <hex value>”
In Delphi IDE in your Windows computer, if your program is complied with debug information, you can locate the line of source code that caused error. The possible reason behind the issue can be Delphi program is the use of an object that has not been created. If you enable ‘Stop on Delphi Exceptions’ in Debugger option window, you may see message says that EAccessViolation has occurred. The EAccessViolation is the exception class for invalid memory access errors.
Reason behind errors and How to Fix Access Violation at address Delphi error in Windows PC?
1: Call a non-existent object
This issue can be occurred due to the Delphi uses an object that has not been created or has been released. You can fix the issue by ensuring that any objects you access are created first. For example, when a Table is located in data module that has not been created, you may open the table in OnCreate event of the form. In the following code, after calling an event that has been deleted, Access Violation at address error appears:
var b:TBitmap;
begin
b:=TBitmap.Create;
try
//Do some things on the b object Operation
finally
b.free;
end;
…
//Because b has been released, an Access violation error will appear
b.Canvas.TextOut (0,0, ‘This is an Access Violation’);
end;
2: Non-existent API parameters
This error can be occurred if you try to pass a non-existent parameters to Win API function. You can fix the issue by consulting the Win API help to see the parameter information and parameter type of this API function call.
3: Let Delphi Release
When an object owns another object, let it do delete work for you. When application ends, it release the application object, which releases all forms. For example, if you automatically create two forms at beginning of program, the following code will cause Access Violation at address error.
unit Unit1;
…
uses unit2;
…
procedure TForm1.Call_Form2
begin
Form2.ShowModal;
Form2.Free;
//Access violation error will appear
Form2.ShowModal;
end;
4: Kill Exceptions
You should never kill temporary exception objects. Handling an exception will automatically release the exception object. If you manually release the exception object, the program will try to release it again, then Access Violation at address error is appeared.
Zero:=0;
try
dummy:= 10/Zero;
except
on E: EZeroDivide do
MessageDlg (‘cannot be done with 0 Divisor! ‘, MtError, [mbOK], 0);
E.free.////Access violation error will appear
end;
5: Retrieve an empty string
If you are not aware, an empty string has no data and if you are trying to retrieve an empty string, you can see Access Violation at address error.
var s: string;
begin
s: = ”;
s [1]: = ‘a’;
//Access violation The error will appear
end;
6: Directly refer to pointer
You must refer to pointer indirectly otherwise you will change the pointer address and many destroy other storage units.
Conclusion
I am sure this post helped you on How to fix Access Violation at address error, Access Violation at address Delphi error in Windows 10/8/7 with several easy steps/methods. You can read & follow our instructions to do so. That’s all. For any suggestions or queries, please write on comment box below.
