Is it possible to have a global exception hook?

Question

my code is fairly well covered with exception handling (try..except). Some exceptions are not expected to happen and some exceptions happen fairly often, which is expected a

Answer 1

I think you can use the AddVectoredExceptionHandler API function.

Here is a small sample on how to use:

var
  f : TFileStream;

    function VectoredHandler(ExceptionInfo : PEXCEPTION_POINTERS): LongInt; stdcall;
    var 
      s : String;
    begin
      S := Format('Exception code %x address %p'#10#13, [ExceptionInfo^.ExceptionRecord^.ExceptionCode,
       ExceptionInfo^.ExceptionRecord^.ExceptionAddress]);
       f.WriteBuffer(PChar(s)^, Length(s) * sizeof(wchar));
       FlushFileBuffers(f.Handle);
      OutputDebugString(PChar(Format('ExceptionCode: %x', [ExceptionInfo^.ExceptionRecord^.ExceptionCode])));
      result := EXCEPTION_CONTINUE_SEARCH ;
    end;


    initialization
      AddVectoredExceptionHandler(0, VectoredHandler);

Answer 2

JCL has it's own exception dialog. Just add this dialog to your project, it will handle all unexpected exceptions. Detailed info located in this JCL folder: jcl\experts\debug. There is also howto text file which step by step describes how to use it.

Answer 3

You can do the following:

• preserve the value of System.RaiseExceptObjProc variable, which in normal Delphi app is pointing to SysUtils.RaiseExceptObject
• create your own "RaiseExceptObject" proc and assign it to the RaiseExceptObjProc variable
• in your own "RaiseExceptObject" proc you can do what you want, then call saved RaiseExceptObjProc value

For details, see above variable and procedure declarations.

Answer 4

You could add a custom handler to madExcept which would then allow you to get a full stack trace, but also carry on.